Web mapping - AbsoluteAstronomy.com

Web mapping is the process of designing, implementing, generating and delivering map

Map

A map is a visual representation of an area—a symbolic depiction highlighting relationships between elements of that space such as objects, regions, and themes....

s on the World Wide Web

World Wide Web

The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

and its product. While web mapping primarily deals with technological issues, web cartography
Cartography
Cartography is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.The fundamental problems of traditional cartography are to:*Set the map's...

additionally studies theoretic aspects: the use of web maps, the evaluation and optimization of techniques and workflows, the usability of web maps, social aspects, and more. Web GIS
Geographic Information System
A geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...

is similar to web mapping but with an emphasis on analysis, processing of project specific geodata

Geoinformation

Geoinformation is an abbreviation of geographic information. Geographic information is created by manipulating geographic data in a computerized system. Systems can include computers and networks, standards and protocols for data use and exchange between users within a range of different...

and exploratory aspects. Often the terms web GIS and web mapping are used synonymously, even if they don't mean exactly the same. In fact, the border between web maps and web GIS is blurry. Web maps are often a presentation media in web GIS and web maps are increasingly gaining analytical capabilities.

A special case of web maps are mobile maps, displayed on mobile computing

Mobile computing

Mobile computing is a form of human–computer interaction by which a computer is expected to be transported during normal usage. Mobile computing has three aspects: mobile communication, mobile hardware, and mobile software...

devices, such as mobile phones, smart phones, PDAs

Personal digital assistant

A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...

and GPS

Global Positioning System

The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

. If the maps on these devices are displayed by a mobile web browser

Web browser

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

or web user agent

User agent

In computing, a user agent is a client application implementing a network protocol used in communications within a client–server distributed computing system...

, they can be regarded as mobile web maps. If the mobile web maps also display context and location sensitive information, such as points of interest, the term Location-based service
Location-based service
A Location-Based Service is an information or entertainment service, accessible with mobile devices through the mobile network and utilizing the ability to make use of the geographical position of the mobile device....

s is frequently used."

"The use of the web as a dissemination medium for maps can be regarded as a major advancement in cartography and opens many new opportunities, such as realtime maps, cheaper dissemination, more frequent and cheaper updates of data and software, personalized map content, distributed data sources and sharing of geographic information

Geoinformation

. It also implicates many challenges due to technical restrictions (low display resolution

Display resolution

The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...

and limited bandwidth

Bandwidth (computing)

In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it .Note that in textbooks on wireless communications, modem data transmission,...

, in particular with mobile computing devices, many of which are physically small, and use slow wireless Internet connections), copyright

Copyright is a legal concept, enacted by most governments, giving the creator of an original work exclusive rights to it, usually for a limited time...

and security issues, reliability issues and technical complexity. While the first web maps were primarily static, due to technical restrictions, today's web maps can be fully interactive

Interactivity

In the fields of information science, communication, and industrial design, there is debate over the meaning of interactivity. In the "contingency view" of interactivity, there are three levels:...

and integrate multiple media. This means that both web mapping and web cartography also have to deal with interactivity, usability

Usability

Usability is the ease of use and learnability of a human-made object. The object of use can be a software application, website, book, tool, machine, process, or anything a human interacts with. A usability study may be conducted as a primary job function by a usability analyst or as a secondary job...

and multimedia

Multimedia

Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which use only rudimentary computer display such as text-only, or...

issues."

A more general term is neogeography

Neogeography

Neogeography literally means "new geography" , and is commonly applied to the usage of geographical techniques and tools used for personal and community activities or for utilization by a non-expert group of users...

Development and implementation

The advent of web mapping can be regarded as a major new trend in cartography

Cartography

Cartography is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.The fundamental problems of traditional cartography are to:*Set the map's...

. Previously, cartography was restricted to a few companies, institutes and mapping agencies, requiring expensive and complex hardware and software as well as skilled cartographers and geomatics engineers. With web mapping, freely available mapping technologies and geodata potentially allow every skilled person to produce web maps, with expensive geodata and technical complexity (data harmonization, missing standards) being two of the remaining barriers preventing web mapping from fully going mainstream. The cheap and easy transfer of geodata across the internet allows the integration of distributed data sources, opening opportunities that go beyond the possibilities of disjoint data storage. Everyone with minimal knowhow and infrastructure can become a geodata provider. These facts can be regarded both as an advantage and a disadvantage. While it allows everyone to produce maps and considerably enlarges the audience, it also puts geodata in the hands of untrained people who potentially violate cartographic and geographic principles and introduce flaws during the preparation, analysis and presentation of geographic and cartographic data.

Types of web maps

A first classification of web maps has been made by Kraak. He distinguished static and dynamic web maps and further distinguished interactive and view only web maps. However, today in the light of an increased number of different web map types, this classification needs some revision. Today, there are additional possibilities regarding distributed data sources, collaborative maps, personalized maps, etc.

Analytic web maps

These web maps offer GIS analysis, either with geodata provided, or with geodata uploaded by the map user. As already mentioned, the borderline between analytic web maps and web GIS is blurry. Often, parts of the analysis are carried out by a serverside GIS and the client displays the result of the analysis. As web clients gain more and more capabilities, this task sharing may gradually shift.

Animated web maps

Animated Maps

Animated mapping

Animated mapping is the application of animation, either computer or video, to add a temporal component to a map displaying change in some dimension. Most commonly the change is shown over time, generally at a greatly changed scale...

show changes in the map over time by animating one of the graphical or temporal variables. Various data and multimedia formats and technologies allow the display of animated web maps: SVG, Adobe Flash, Java, Quicktime, etc., also with varying degrees of interaction. Examples for animated web maps are weather maps, maps displaying dynamic natural or other phenomena (such as water currents, wind patterns, traffic flow, trade flow, communication patterns,social studies projects, and for college life, etc.).

Collaborative web maps

Collaborative maps

Collaborative mapping

Collaborative mapping is the aggregation of web maps and user-generated content, from a group of individuals or entities, and can take several distinct forms.-Types:...

are still new, immature and complex to implement, but show a lot of potential. The method parallels the Wikipedia

Wikipedia

Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...

project where various people collaborate to create and improve maps on the web. Technically, an application allowing simultaneous editing across the web would have to ensure that geometric features being edited by one person are locked

File locking

File locking is a mechanism that restricts access to a computer file by allowing only one user or process access at any specific time. Systems implement locking to prevent the classic interceding update scenario ....

, so they can't be edited by other persons at the same time. Also, a minimal quality check would have to be made, before data goes public. Some collaborative map projects:

Google Map Maker
Google Map Maker
Google Map Maker is a service launched by Google in June 2008, designed to expand the breadth of the service currently offered by Google Maps. In some countries mapping data is unavailable, and so to combat this problem Google has decided to open up Google Maps to a collaborative community effort...
OpenStreetMap
OpenStreetMap
OpenStreetMap is a collaborative project to create a free editable map of the world. Two major driving forces behind the establishment and growth of OSM have been restrictions on use or availability of map information across much of the world and the advent of inexpensive portable GPS devices.The...
WikiMapia
Wikimapia
WikiMapia is a privately owned, online map and satellite imaging resource that combines Google Maps with a wiki system, allowing users to add information, in the form of a note, to any location on Earth. Users may currently use this information for free...
meta:Maps - survey of Wikimedia map proposals on Wikipedia:Meta
(Please add additional notes, references and examples here!)

Customisable web maps

Web maps in this category are usually more complex web mapping systems that offer APIs for reuse in other people's web pages and products. Example for such a system with an API for reuse are the Open Layers Framework, Yahoo! Maps, Google Maps and Streetmaps.co.za.

Distributed web maps

These are maps created from a distributed data source. The WMS

Web Map Service

A Web Map Service is a standard protocol for serving georeferenced map images over the Internet that are generated by a map server using data from a GIS database...

protocol offers a standardised method to access maps on other servers. WMS servers can collect these different sources, reproject the map layers, if necessary, and send them back as a combined image containing all requested map layers. One server may offer a topographic base map, while other servers may offer thematic layers.

Dynamically created web maps

These maps are created on demand each time the user reloads the webpages, often from dynamic data sources, such as databases. The webserver generates the map using a web map server or a self written software. Some applications refer to depictions as hyper maps.
One of the example is- Bhoosampada

Bhoosampada

Bhoosampada is an Information portal of Indian Space Research Organisation . It was dedicated to the nation on 28 January 2009 by Chairman ISRO at National Remote Sensing Centre, Hyderabad...

by Indian Space Research Organizations.

Hyper Maps

Any approach offering the planar presentation of a portion of an n-dimensional orthogonal web map structure with the option to chose the axes for depiction from the dimensions.

Interactive web maps

Interactivity is one of the major advantages of screen based maps and web maps. It helps to compensate for the disadvantages of screen and web maps. Interactivity helps to explore maps, change map parameters, navigate and interact with the map, reveal additional information, link to other resources, and much more. Technically, it is achieved through the combination of events, scripting and DOM manipulations. See section on Client Side Technologies.

Online atlases

Atlas projects often went through a renaissance when they made a transition to a web based project. In the past, atlas projects often suffered from expensive map production, small circulation and limited audience. Updates were expensive to produce and took a long time until they hit the public. Many atlas projects, after moving to the web, can now reach a wider audience, produce cheaper, provide a larger number of maps and map types and integrate with and benefit from other web resources. Some atlases even ceased their printed editions after going online, sometimes offering printing on demand features from the online edition. Some atlases (primarily from North America) also offer raw data downloads of the underlying geospatial data sources.

Personalized web maps

Personalized web maps allow the map user to apply his own data filtering, selective content and the application of personal styling and map symbolization. The OGC (Open Geospatial Consortium)

Open Geospatial Consortium

The Open Geospatial Consortium , an international voluntary consensus standards organization, originated in 1994. In the OGC, more than 400 commercial, governmental, nonprofit and research organizations worldwide collaborate in a consensus process encouraging development and implementation of open...

provides the SLD standard (Styled Layer Description) that may be sent to a WMS server for the application of individual styles. This implies that the content and data structure of the remote WMS server is properly documented.

Realtime web maps

Realtime maps show the situation of a phenomenon in close to realtime (only a few seconds or minutes delay). Data is collected by sensors and the maps are generated or updated at regular intervals or immediately on demand. Examples are weather maps, traffic maps or vehicle monitoring systems.

Static web maps

Static web page

Web page

A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

s are view only
Read-only
In computing, read-only can mean:* Read-only memory , a type of storage media* Read-only access to files or directories in file system permissions...

with no animation

Animation

Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement. The effect is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in several ways...

and interactivity

Interactivity

In the fields of information science, communication, and industrial design, there is debate over the meaning of interactivity. In the "contingency view" of interactivity, there are three levels:...

. They are only created once, often manually and infrequently updated. Typical graphics formats for static web maps are PNG, JPEG

JPEG

In computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....

, GIF

GIF

The Graphics Interchange Format is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability....

, or TIFF (e.g., drg

Digital raster graphic

A digital raster graphic is a digital image resulting from scanning a paper USGS topographic map for use on a computer. DRGs created by USGS are typically scanned at 250 dpi and saved as a TIFF. The raster image usually includes the original border information, referred to as the "map collar". ...

) for raster

Raster graphics

In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...

files, SVG, PDF or SWF

SWF

SWF is an Adobe Flash file format used for multimedia, vector graphics and ActionScript. Originating with FutureWave Software, then transferred to Macromedia, and then coming under the control of Adobe, SWF files can contain animations or applets of varying degrees of interactivity and function.,...

for vector

Vector graphics

Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon, which are all based on mathematical expressions, to represent images in computer graphics...

files. Often, these maps are scanned

Image scanner

In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...

paper maps and had not been designed as screen maps. Paper maps have a much higher resolution

Dots per inch

Dots per inch is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch . The DPI value tends to correlate with image resolution, but is related only indirectly.- DPI measurement in monitor...

and information density than typical computer displays of the same physical size, and might be unreadable when displayed on screens at the wrong resolution

Display resolution

Temporal web maps

Any depiction of a portion of an n-dimensional orthogonal web map structure in a planar projection with time as one of the coordinate axes.

Advantages of web maps

Web maps can easily deliver up to date information. If maps are generated automatically from database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

s, they can display information in almost realtime
Real-time computing
In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...

. They don't need to be printed
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....

, mastered and distributed. Examples:
- A map displaying election
  Election
  An election is a formal decision-making process by which a population chooses an individual to hold public office. Elections have been the usual mechanism by which modern representative democracy operates since the 17th century. Elections may fill offices in the legislature, sometimes in the...
  
  results, as soon as the election results become available.
- A map displaying the traffic situation near realtime by using traffic data collected by sensor networks.
- A map showing the current locations of mass transit vehicles such as bus
  Bus
  A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...
  
  es or train
  Light rail
  Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...
  
  s, allowing patrons to minimize their waiting time at stops or stations, or be aware of delays in service.
- Weather maps
  Surface weather analysis
  Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations...
  
  , such as NEXRAD
  NEXRAD
  NEXRAD or Nexrad is a network of 159 high-resolution Doppler weather radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration within the United States Department of Commerce...
  
  .
Software and hardware
Computer hardware
Personal computer hardware are component devices which are typically installed into or peripheral to a computer case to create a personal computer upon which system software is installed including a firmware interface such as a BIOS and an operating system which supports application software that...

infrastructure
Infrastructure
Infrastructure is basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function...

for web maps is cheap. Web server
Web server
Web server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....

hardware
Server farm
A server farm or server cluster is a collection of computer servers usually maintained by an enterprise to accomplish server needs far beyond the capability of one machine. Server farms often have backup servers, which can take over the function of primary servers in the event of a primary server...

is cheaply available and many open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

tools exist for producing web maps.
Product updates can easily be distributed. Because web maps distribute both logic and data with each request or loading, product updates can happen every time the web user reloads the application. In traditional cartography
Cartography
Cartography is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.The fundamental problems of traditional cartography are to:*Set the map's...

, when dealing with printed maps or interactive maps distributed on offline media (CD, DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

, etc.), a map update caused serious efforts, triggering a reprint or remastering as well as a redistribution of the media. With web maps, data and product updates are easier, cheaper, and faster, and can occur more often.
They work across browsers
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

and operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s. If web maps are implemented based on open standards, the underlying operating system and browser do not matter.
Web maps can combine distributed data sources. Using open standards and documented API
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...

s one can integrate (mash up
Mashup (web application hybrid)
In Web development, a mashup is a Web page or application that uses and combines data, presentation or functionality from two or more sources to create new services...

) different data sources, if the projection system
Map projection
A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane. Map projections are necessary for creating maps. All map projections distort the surface in some fashion...

, map scale and data quality match. The use of centralized data sources removes the burden for individual organizations to maintain copies of the same data sets. The downside is that one has to rely on and trust the external data sources.
Web maps allow for personalization. By using user profiles
Configuration file
In computing, configuration files, or config files configure the initial settings for some computer programs. They are used for user applications, server processes and operating system settings. The files are often written in ASCII and line-oriented, with lines terminated by a newline or carriage...

, personal filters and personal styling and symbolization, users can configure and design their own maps, if the web mapping systems supports personalization. Accessibility issues can be treated in the same way. If users can store their favourite colors and patterns they can avoid color combinations they can't easily distinguish (e.g. due to color blindness
Color blindness
Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under lighting conditions when color vision is not normally impaired...

).
Web maps enable collaborative mapping. Similar to the Wikipedia
Wikipedia
Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 20 million articles have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,...

project, web mapping technologies, such as DHTML/Ajax
Ajax (programming)
Ajax is a group of interrelated web development methods used on the client-side to create asynchronous web applications...

, SVG
Scalable Vector Graphics
Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...

, Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

, Adobe Flash
Adobe Flash
Adobe Flash is a multimedia platform used to add animation, video, and interactivity to web pages. Flash is frequently used for advertisements, games and flash animations for broadcast...

, etc. enable distributed data acquisition and collaborative efforts. Examples for such projects are the OpenStreetMap
OpenStreetMap
OpenStreetMap is a collaborative project to create a free editable map of the world. Two major driving forces behind the establishment and growth of OSM have been restrictions on use or availability of map information across much of the world and the advent of inexpensive portable GPS devices.The...

project or the Google Earth
Google Earth
Google Earth is a virtual globe, map and geographical information program that was originally called EarthViewer 3D, and was created by Keyhole, Inc, a Central Intelligence Agency funded company acquired by Google in 2004 . It maps the Earth by the superimposition of images obtained from satellite...

community. As with other open projects, quality assurance is very important, however!
Web maps support hyperlink
Hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...

ing to other information on the web. Just like any other web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

or a wiki
Wiki
A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...

, web maps can act like an index to other information on the web. Any sensitive area
Image map
In HTML and XHTML , an image map is a list of coordinates relating to a specific image, created in order to hyperlink areas of the image to various destinations . For example, a map of the world may have each country hyperlinked to further information about that country...

in a map, a label text, etc. can provide hyperlinks to additional information. As an example a map showing public transport options can directly link to the corresponding section in the online train time table.
It is easy to integrate multimedia
Multimedia
Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which use only rudimentary computer display such as text-only, or...

in and with web maps. Current web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

s support the playback of video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...

, audio
Sound recording and reproduction
Sound recording and reproduction is an electrical or mechanical inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording...

and animation
Animation
Animation is the rapid display of a sequence of images of 2-D or 3-D artwork or model positions in order to create an illusion of movement. The effect is an optical illusion of motion due to the phenomenon of persistence of vision, and can be created and demonstrated in several ways...

(SVG
Scalable Vector Graphics
Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...

, SWF
SWF
SWF is an Adobe Flash file format used for multimedia, vector graphics and ActionScript. Originating with FutureWave Software, then transferred to Macromedia, and then coming under the control of Adobe, SWF files can contain animations or applets of varying degrees of interactivity and function.,...

, Quicktime
QuickTime
QuickTime is an extensible proprietary multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. The classic version of QuickTime is available for Windows XP and later, as well as Mac OS X Leopard and...

, and other multimedia framework
Multimedia framework
A multimedia framework is a software framework that handles media on a computer and through a network. A good multimedia framework offers an intuitive API and a modular architecture to easily add support for new audio, video and container formats and transmission protocols...

s).

Disadvantages of web maps and problematic issues

Reliability issues – the reliability of the internet and web server infrastructure is not yet good enough. Especially if a web map relies on external, distributed data sources, the original author often cannot guarantee the availability of the information.
Geodata is expensive – Unlike in the US, where geodata collected by governmental institutions is usually available for free or cheap, geodata is usually very expensive in Europe or other parts of the world.
Bandwidth issues – Web maps usually need a relatively high bandwidth.
Quality and accuracy issues – Many web maps are of poor quality, both in symbolization, content and data accuracy.
Complex to develop – Despite the increasing availability of free and commercial tools to create web mapping and web GIS applications, it is still a complex task to create interactive web maps. Many technologies, modules, services and data sources have to be mastered and integrated.
Immature development tools – Compared to the development of standalone applications with integrated development tools, the development and debugging environments of a conglomerate of different web technologies is still awkward and uncomfortable.
Copyright issues – Many people are still reluctant to publish geodata, especially in the light that geodata is expensive in some parts of the world. They fear copyright infringements of other people using their data without proper requests for permission.
Privacy issues – With detailed information available and the combination of distributed data sources, it is possible to find out and combine a lot of private and personal information of individual persons. Properties and estates of individuals are now accessible through high resolution aerial and satellite images throughout the world to anyone.

History of web mapping

Event types
*Cartography-related events* Technical events directly related to web mapping General technical events Events relating to Web standards Web standards Web standards is a general term for the formal standards and other technical specifications that define and describe aspects of the World Wide Web. In recent years, the term has been more frequently associated with the trend of endorsing a set of standardized best practices for building web sites,...

This section contains some of the milestones of web mapping, online mapping services and atlases. Because web mapping depends on enabling technologies of the web, this section also includes a few milestones of the web.

1989-90: Birth of the WWW, WWW invented at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...

for the exchange of research documents.
1990-12: First Web Browser and Web Server, Tim Berners-Lee
Tim Berners-Lee
Sir Timothy John "Tim" Berners-Lee, , also known as "TimBL", is a British computer scientist, MIT professor and the inventor of the World Wide Web...

wrote first web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

and web server
Web server
Web server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....

.
1991-04: HTTP 0.9 protocol, Initial design of the HTTP protocol for communication between browser and server.
1991-06: ViolaWWW
ViolaWWW
ViolaWWW, first developed in the early 1990s, for Unix and the X Windowing System, was the first popular web browser which, until Mosaic, was the most frequently used web browser for access to the World Wide Web...

0.8 Browser, The first popular web browser. Written for X11 on Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

.
1991-08: http://groups.google.com/group/alt.hypertext/tree/browse_frm/thread/7824e490ea164c06/f61c1ef93d2a8398?rnum=1&hl=en&q=group%3Aalt.hypertext+author%3ATim+author%3ABerners-Lee&_done=%2Fgroup%2Falt.hypertext%2Fbrowse_frm%2Fthread%2F7824e490ea164c06%2Ff61c1ef93d2a8398%3Ftvc%3D1%26q%3Dgroup%3Aalt.hypertext+author%3ATim+author%3ABerners-Lee%26hl%3Den%26#doc_06dad279804cb3baWWW project announced in public newsgroup], This is regarded as the debut date of the Web. Announced in newsgroup
Newsgroup
A usenet newsgroup is a repository usually within the Usenet system, for messages posted from many users in different locations. The term may be confusing to some, because it is usually a discussion group. Newsgroups are technically distinct from, but functionally similar to, discussion forums on...

alt.hypertext.
1992-06: HTTP 1.0 protocol, Version 1.0 of the HTTP protocol. Introduces the POST method and persistent connections
HTTP persistent connection
HTTP persistent connection, also called HTTP keep-alive, or HTTP connection reuse, is the idea of using the same TCP connection to send and receive multiple HTTP requests/responses, as opposed to opening a new connection for every single request/response pair.- Operation :Under HTTP 1.0, there is...

.
1993-04: CERN announced web as free, CERN announced that access to the web will be free for all. The web gained critical mass
Critical mass (sociodynamics)
Critical mass is a sociodynamic term to describe the existence of sufficient momentum in a social system such that the momentum becomes self-sustaining and creates further growth....

.
1993-06: HTML 1.0. The first version of HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

, published by T. Berners-Lee and Dan Connolly
Dan Connolly
Dan Connolly received a B.S. in Computer Science from the University of Texas at Austin in 1990. His research interests include investigating the value of formal descriptions of chaotic systems like the Web, particularly in the consensus-building process, and the Semantic Web.He became involved...

.
1993-07: Xerox PARC Map Viewer
Xerox PARC Map Viewer
Xerox PARC Map Viewer was one of the earliest static web mapping sites, developed by Steve Putz in June 1993 at Xerox Corporation's Palo Alto Research Center...

, The first mapserver based on CGI
Common Gateway Interface
The Common Gateway Interface is a standard method for web servers software to delegate the generation of web pages to executable files...

/Perl
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...

, allowed reprojection styling and definition of map extent.
1994: The World Wide Earthquake Locator, the first interactive web mapping mashup was released, based on the Xerox PARC map view.
1994-06: The National Atlas of Canada, The first version of the National Atlas of Canada was released. Can be regarded as the first online atlas.
1994-10: Netscape Browser 0.9 (Mosaic
Mosaic (web browser)
Mosaic is the web browser credited with popularizing the World Wide Web. It was also a client for earlier protocols such as FTP, NNTP, and gopher. Its clean, easily understood user interface, reliability, Windows port and simple installation all contributed to making it the application that opened...

), The first version of the highly popular browser Netscape Navigator
Netscape Navigator
Netscape Navigator was a proprietary web browser that was popular in the 1990s. It was the flagship product of the Netscape Communications Corporation and the dominant web browser in terms of usage share, although by 2002 its usage had almost disappeared...

.
1995: The Gazetteer for Scotland, The prototype version of the Gazetteer for Scotland was released. The first geographical database with interactive mapping.
1995-03: Java 1.0, The first public version of Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...

.
1995-11: HTML 2.0, Introduced forms
Form (web)
A webform on a web page allows a user to enter data that is sent to a server for processing. Webforms resemble paper or database forms because internet users fill out the forms using checkboxes, radio buttons, or text fields...

, file upload
Uploading and downloading
In computer networks, to download means to receive data to a local system from a remote system, or to initiate such a data transfer. Examples of a remote system from which a download might be performed include a webserver, FTP server, email server, or other similar systems...

, internationalization
Internationalization
In economics, internationalization has been viewed as a process of increasing involvement of enterprises in international markets, although there is no agreed definition of internationalization or international entrepreneurship...

and client-side image map
Image map
In HTML and XHTML , an image map is a list of coordinates relating to a specific image, created in order to hyperlink areas of the image to various destinations . For example, a map of the world may have each country hyperlinked to further information about that country...

s.
1995-12: Javascript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

1.0, Introduced first script based interactivity.
1995: MapGuide
MapGuide Open Source
MapGuide Open Source is a web-based map-making platform that enables users to quickly develop and deploy web mapping applications and geospatial web services...

, First introduced as Argus MapGuide.
1996-01: JDK
Java Development Kit
The Java Development Kit is an Oracle Corporation product aimed at Java developers. Since the introduction of Java, it has been by far the most widely used Java SDK. On 17 November 2006, Sun announced that it would be released under the GNU General Public License , thus making it free software...

1.0, First version of the Sun
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

JDK.

1996-02: Mapquest
MapQuest
MapQuest is an American free online web mapping service owned by AOL. The company was founded in 1967 as Cartographic Services, a division of R.R. Donnelley & Sons in Chicago, Illinois, United States. It moved to Lancaster, Pennsylvania in 1969. When it became an independent company in 1994, it was...

, The first popular online Address Matching and Routing Service with mapping output.
1996-06: MultiMap
Multimap.com
Multimap.com was a United Kingdom based provider of mapping and location-based services. It was acquired by Microsoft in 2007 and merged into Bing Maps in 2010.-History:...

, The UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

-based MultiMap website launched offering online mapping, routing and location based services. Grew into one of the most popular UK web sites.
1996-11: Geomedia WebMap 1.0, First version of Geomedia WebMap, already supports vector graphics through the use of ActiveCGM.
1996-fall: MapGuide
MapGuide Open Source
MapGuide Open Source is a web-based map-making platform that enables users to quickly develop and deploy web mapping applications and geospatial web services...

, Autodesk acquired Argus Technologies.and introduced Autodesk MapGuide 2.0.
1996-12: Macromedia Flash 1.0, First version of the Macromedia Flash plugin.
1997-01: HTML 3.2, Introduced tables, applets, script elements, multimedia elements, flowtext around images, etc.

1997-03:Norwegian company Mapnet launches application for www.epi.no with active POI layer for real estate listings.
1997-06: US Online National Atlas Initiative, The USGS
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

received the mandate to coordinate and create the online National Atlas of the United States of America http://www.nationalatlas.gov/.
1997-07: UMN MapServer
MapServer
MapServer is an open source development environment for building spatially-enabled internet applications. It can run as a CGI program or via MapScript which supports several programming languages . MapServer was developed by the University of Minnesota — so, it is often and more specifically...

1.0, Developed as Part of the NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

ForNet Project. Grew out of the need to deliver remote sensing
Remote sensing
Remote sensing is the acquisition of information about an object or phenomenon, without making physical contact with the object. In modern usage, the term generally refers to the use of aerial sensor technologies to detect and classify objects on Earth by means of propagated signals Remote sensing...

data across the web for foresters
Forestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...

.
1997-12: HTML 4.0, Introduced styling with CSS
Cascading Style Sheets
Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...

, absolute and relative positioning of elements, frames, object element, etc.
1998-06: Terraserver
TerraServer
Terraserver refers to one of two databases for viewing geospatial imagery:* Terraserver.com, a commercial web site operated by TerraServer.com, Inc. of Raleigh, North Carolina....

USA, A Web Map Service
Web Map Service
A Web Map Service is a standard protocol for serving georeferenced map images over the Internet that are generated by a map server using data from a GIS database...

serving aerial image
Aerial image
An aerial image is a projected image which is "floating in air", and cannot be viewed normally. It can only be seen from one position in space, often focused by another lens....

s (mainly b+w) and USGS DRG
Digital raster graphic
A digital raster graphic is a digital image resulting from scanning a paper USGS topographic map for use on a computer. DRGs created by USGS are typically scanned at 250 dpi and saved as a TIFF. The raster image usually includes the original border information, referred to as the "map collar". ...

s was released. One of the first popular WMS. This service is a joint effort of USGS, Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

and HP
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

.
1998-07: UMN MapServer 2.0, Added reprojection
Map projection
A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane. Map projections are necessary for creating maps. All map projections distort the surface in some fashion...

support (PROJ.4).
1998-08: MapObjects Internet Map Server, ESRI
ESRI
Esri is a software development and services company providing Geographic Information System software and geodatabase management applications. The headquarters of Esri is in Redlands, California....

's entry into the web mapping business.
1999-03: HTTP 1.1 protocol, Version 1.1 of the HTTP protocol. Introduces the request pipelining for multiple connections between server and client. This version is still in use as of 2007.
1999-08: National Atlas of Canada, 6th edition, This new version was launched at the ICA 1999 conference in Ottawa. Introduced many new features and topics. Is being improved gradually, since then, and kept up-to-date with technical advancements.
2000-02: ArcIMS 3.0, The first public release of ESRI's ArcIMS
ArcIMS
ArcIMS is a Web Map Server produced by Esri. It is a GIS that is designed to serve maps across the Internet. Sometimes these maps are just static images allowing simple panning and zooming, while others are more complex pages...

.
2000-06: ESRI Geography Network, ESRI founded Geography Network to distribute data and web map services.
2000-06: UMN MapServer 3.0, Developed as part of the NASA TerraSIP Project. This is also the first public, open source release of UMN Mapserver. Added raster support and support for TrueType fonts (FreeType).
2000-08: Flash Player 5, This introduced ActionScript
ActionScript
ActionScript is an object-oriented language originally developed by Macromedia Inc. . It is a dialect of ECMAScript , and is used primarily for the development of websites and software targeting the Adobe Flash Player platform, used on Web pages in the form of...

1.0 (ECMAScript
ECMAScript
ECMAScript is the scripting language standardized by Ecma International in the ECMA-262 specification and ISO/IEC 16262. The language is widely used for client-side scripting on the web, in the form of several well-known dialects such as JavaScript, JScript, and ActionScript.- History :JavaScript...

compatible).
2001-06: MapScript http://mapserver.gis.umn.edu/docs/faq/mapscript/?searchterm=MapScript 1.0 for UMN MapServer, Adds a lot of flexibility to UMN MapServer solutions.
2001-09: SVG 1.0 W3C Recommendation, SVG (Scalable Vector Graphics
Scalable Vector Graphics
Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...

) 1.0 became a W3C Recommendation.
2001-09: Tirolatlas, A highly interactive online atlas, the first to be based on the SVG standard.
2002-06: UMN MapServer 3.5, Added support for PostGIS
PostGIS
PostGIS is an open source software program that adds support for geographic objects to the PostgreSQL object-relational database. PostGIS follows the Simple Features for SQL specification from the Open Geospatial Consortium .-Features:...

and ArcSDE
ArcSDE
ArcSDE is a server-software sub-system that aims to enable the usage of Relational Database Management Systems for spatial data...

. Version 3.6 adds initial OGC
Open Geospatial Consortium
The Open Geospatial Consortium , an international voluntary consensus standards organization, originated in 1994. In the OGC, more than 400 commercial, governmental, nonprofit and research organizations worldwide collaborate in a consensus process encouraging development and implementation of open...

WMS support.
2002-07: ArcIMS 4.0, Version 4 of the ArcIMS
ArcIMS
ArcIMS is a Web Map Server produced by Esri. It is a GIS that is designed to serve maps across the Internet. Sometimes these maps are just static images allowing simple panning and zooming, while others are more complex pages...

web map server.
2003-01: SVG 1.1 W3C Recommendation, SVG 1.1 became a W3C Recommendation. This introduced the mobile profiles SVG Tiny and SVG Basic.

2003-06: NASA World Wind
NASA World Wind
World Wind is an open-source virtual globe developed by NASA and the open source community for use on personal computers. Old versions need Microsoft Windows but the more recent Java version, , is cross platform and provides a suite of . The World Wind Java version was awarded in November 2009...

, NASA World Wind Released. An open virtual globe
Virtual globe
A virtual globe is a 3D software model or representation of the Earth or another world. A virtual globe provides the user with the ability to freely move around in the virtual environment by changing the viewing angle and position. Compared to a conventional globe, virtual globes have the...

that loads data from distributed resources across the internet. Terrain and buildings can be viewed 3 dimensionally. The (XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

based) markup language allows users to integrate their own personal content. This virtual globe needs special software and doesn't run in a web browser.
2003-07: UMN MapServer 4.0, Adds 24bit raster output support and support for PDF
Portable Document Format
Portable Document Format is an open standard for document exchange. This file format, created by Adobe Systems in 1993, is used for representing documents in a manner independent of application software, hardware, and operating systems....

and SWF
SWF
SWF is an Adobe Flash file format used for multimedia, vector graphics and ActionScript. Originating with FutureWave Software, then transferred to Macromedia, and then coming under the control of Adobe, SWF files can contain animations or applets of varying degrees of interactivity and function.,...

.
2003-09: Flash Player 7, This introduced ActionScript
ActionScript
ActionScript is an object-oriented language originally developed by Macromedia Inc. . It is a dialect of ECMAScript , and is used primarily for the development of websites and software targeting the Adobe Flash Player platform, used on Web pages in the form of...

2.0 (ECMAScript
ECMAScript
ECMAScript is the scripting language standardized by Ecma International in the ECMA-262 specification and ISO/IEC 16262. The language is widely used for client-side scripting on the web, in the form of several well-known dialects such as JavaScript, JScript, and ActionScript.- History :JavaScript...

2.0 compatible (improved object orientation)). Also initial Video Playback support.
2004-07: OpenStreetMap
OpenStreetMap
OpenStreetMap is a collaborative project to create a free editable map of the world. Two major driving forces behind the establishment and growth of OSM have been restrictions on use or availability of map information across much of the world and the advent of inexpensive portable GPS devices.The...

was founded by Steve Coast. OSM is a web based collaborative project to create a world map under a free license.
2005-01: Nikolas Schiller creates the interactive "Inaugural Map" of downtown Washington, DC
2005-02: Google Maps
Google Maps
Google Maps is a web mapping service application and technology provided by Google, free , that powers many map-based services, including the Google Maps website, Google Ride Finder, Google Transit, and maps embedded on third-party websites via the Google Maps API...

, The first version of Google Maps. Based on raster tiles organized in a quad tree scheme, data loading done with XMLHttpRequest
XMLHttpRequest
XMLHttpRequest is an API available in web browser scripting languages such as JavaScript. It is used to send HTTP or HTTPS requests directly to a web server and load the server response data directly back into the script. The data might be received from the server as XML text or as plain text...

s. This mapping application became highly popular on the web, also because it allowed other people to integrate google map services into their own website.
2005-04: UMN MapServer 4.6, Adds support for SVG.

2005-06: Google Earth
Google Earth
Google Earth is a virtual globe, map and geographical information program that was originally called EarthViewer 3D, and was created by Keyhole, Inc, a Central Intelligence Agency funded company acquired by Google in 2004 . It maps the Earth by the superimposition of images obtained from satellite...

, The first version of Google Earth was released building on the virtual globe metaphor. Terrain and buildings can be viewed 3 dimensionally. The KML
Keyhole Markup Language
Keyhole Markup Language is an XML notation for expressing geographic annotation and visualization within Internet-based, two-dimensional maps and three-dimensional Earth browsers. KML was developed for use with Google Earth, which was originally named Keyhole Earth Viewer. It was created by...

(XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

based) markup language allows users to integrate their own personal content. This virtual globe needs special software and doesn't run in a web browser.
2005-11: Firefox 1.5, First Firefox release with native SVG support. Supports Scripting but no animation.
2006-05: Wikimapia
Wikimapia
WikiMapia is a privately owned, online map and satellite imaging resource that combines Google Maps with a wiki system, allowing users to add information, in the form of a note, to any location on Earth. Users may currently use this information for free...

Launched
2006-06: Opera 9, Opera
Opera (web browser)
Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...

releases version 9 with extensive SVG support (including scripting and animation).
2006-08: SVG 1.2 Mobile Candidate Recommendation, This SVG Mobile Profile introduces improved multimedia support and many features required to build online Rich Internet Applications.
2009-01 Nokia
Nokia
Nokia Corporation is a Finnish multinational communications corporation that is headquartered in Keilaniemi, Espoo, a city neighbouring Finland's capital Helsinki...

makes Ovi Maps free on its smartphones.

Web mapping technologies

The potential number of technologies to implement web mapping projects is almost infinite. Any programming environment, programming language and serverside framework can be used to implement web mapping projects. In any case, both server and client side technologies have to be used. Following is a list of potential and popular server and client side technologies utilized for web mapping.

Server side technologies

Web server – The webserver is responsible for handling http requests by web browsers and other user agents. In the simplest case they serve static files, such as HTML pages or static image files. Web servers also handle authentication, content negotiation, server side includes, URL rewriting and forward requests to dynamic resources, such as CGI applications or serverside scripting languages. The functionality of a webserver can usually be enhanced using modules or extensions. The most popular web server is Apache
Apache HTTP Server
The Apache HTTP Server, commonly referred to as Apache , is web server software notable for playing a key role in the initial growth of the World Wide Web. In 2009 it became the first web server software to surpass the 100 million website milestone...

, followed by Microsoft Internet Information Server
Internet Information Services
Internet Information Services – formerly called Internet Information Server – is a web server application and set of feature extension modules created by Microsoft for use with Microsoft Windows. It is the most used web server after Apache HTTP Server. IIS 7.5 supports HTTP, HTTPS,...

and others.
- CGI (common gateway interface)
  Common Gateway Interface
  The Common Gateway Interface is a standard method for web servers software to delegate the generation of web pages to executable files...
  
  applications are executables running on the webserver under the environment and user permissions of the webserver user. They may be written in any programming language (compiled) or scripting language (e.g. perl). A CGI application implements the common gateway interface protocol, processes the information sent by the client, does whatever the application should do and sends the result back in a web-readable form to the client. As an example a web browser may send a request to a CGI application for getting a web map with a certain map extent
  Map extent
  A map extent is the portion of area of a region show in a map. The limits of a map extent are defined in the coordinate system of the map. In Western culture, map extents usually have a rectangular shape, so they are defined with a minimum and maximum width and height....
  
  , styling and map layer combination. The result is an image format, e.g. JPEG, PNG or SVG. For performance enhancements one can also install CGI applications such as FastCGI
  FastCGI
  FastCGI is a protocol for interfacing interactive programs with a web server. FastCGI is a variation on the earlier Common Gateway Interface ; FastCGI's main aim is to reduce the overhead associated with interfacing the web server and CGI programs, allowing a server to handle more web page...
  
  . This loads the application after the web server is started and keeps the application in memory, eliminating the need to spawn a separate process each time a request is being made.
- Alternatively, one can use scripting languages built into the webserver as a module, such as PHP, Perl, Python, ASP, Ruby, etc. If built into the web server as a module, the scripting engine is already loaded and doesn't have to be loaded each time a request is being made.
Web application servers are middleware
Middleware
Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...

which connects various software components with the web server and a programming language. As an example, a web application server can enable the communication between the API of a GIS and the webserver, a spatial database or other proprietary applications. Typical web application servers are written in Java, C, C++, C# or other scripting languages. Web application servers are also useful when developing complex realtime web mapping applications or Web GIS.
Spatial databases
Spatial Database
A spatial database is a database that is optimized to store and query data that is related to objects in space, including points, lines and polygons. While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases to...

are usually object relational databases enhanced with geographic data types, methods and properties. They are necessary whenever a web mapping application has to deal with dynamic data (that changes frequently) or with huge amount of geographic data. Spatial databases allow spatial queries, sub selects, reprojections, geometry manipulations and offer various import and export formats. A popular example for an open source spatial database is PostGIS
PostGIS
PostGIS is an open source software program that adds support for geographic objects to the PostgreSQL object-relational database. PostGIS follows the Simple Features for SQL specification from the Open Geospatial Consortium .-Features:...

. MySQL
MySQL
MySQL officially, but also commonly "My Sequel") is a relational database management system that runs as a server providing multi-user access to a number of databases. It is named after developer Michael Widenius' daughter, My...

also implements some spatial features, although not as mature as PostGIS. Commercial alternatives are Oracle Spatial
Oracle Spatial
Oracle Spatial forms a separately-licensed option component of the Oracle Database. Oracle Spatial aids users in managing geographic and location-data in a native type within an Oracle database, potentially supporting a wide range of applications — from automated mapping/facilities-management and...

or spatial extensions of Microsoft SQL Server and IBM DB2. The OGC
Open Geospatial Consortium
The Open Geospatial Consortium , an international voluntary consensus standards organization, originated in 1994. In the OGC, more than 400 commercial, governmental, nonprofit and research organizations worldwide collaborate in a consensus process encouraging development and implementation of open...

Simple Features for SQL
Simple Features
Simple feature access , is both an OpenGIS and ISO Standard that specifies a common storage model of geographical data using well-known text . The geometries are also associated with spatial reference systems...

Specification is a standard geometry data model and operator set for spatial databases. Most spatial databases implement this OGC standard.
WMS server
Web Map Service
A Web Map Service is a standard protocol for serving georeferenced map images over the Internet that are generated by a map server using data from a GIS database...

are specialized web mapping servers implemented as a CGI application, Java Servlet or other web application server. They either work as a standalone web server or in collaboration with existing web servers or web application servers (the general case). WMS Servers can generate maps on request, using parameters, such as map layer order, styling/symbolization, map extent, data format, projection, etc. The OGC Consortium defined the WMS
Web Map Service
A Web Map Service is a standard protocol for serving georeferenced map images over the Internet that are generated by a map server using data from a GIS database...

standard to define the map requests and return data formats. Typical image formats for the map result are PNG, JPEG, GIF or SVG. There are open source WMS Servers such as UMN Mapserver
MapServer
MapServer is an open source development environment for building spatially-enabled internet applications. It can run as a CGI program or via MapScript which supports several programming languages . MapServer was developed by the University of Minnesota — so, it is often and more specifically...

and Mapnik
Mapnik
Mapnik is an open source mapping toolkit, written in C++ and useful for both desktop- and server-based map rendering. One of its many users is the OpenStreetMap project which uses it in combination with an Apache Web Server module to render tiles that make up the OSM 'Slippy Map' Layer...

. Commercial alternatives exist from most commercial GIS vendors, such as ESRI ArcIMS
ArcIMS
ArcIMS is a Web Map Server produced by Esri. It is a GIS that is designed to serve maps across the Internet. Sometimes these maps are just static images allowing simple panning and zooming, while others are more complex pages...

, ArcGIS Server, GeoClip, Intergraph Geomedia WebMap, and others.

Client side technologies

Web browser – In the simplest setup, only a web browser is required. All modern web browsers support the display of HTML and raster images (JPEG, PNG and GIF format). Some solutions require additional plugins (see below).
- ECMAScript support – ECMAScript is the standardized version of JavaScript. It is necessary to implement client side interaction, refactoring of the DOM of a webpage and for doing network requests. ECMAScript is currently part of any modern web browser.
- Events support – Various events are necessary to implement interactive client side maps. Events can trigger script execution or SMIL operations. We distinguish between:
  - Mouse events (mousedown, mouseup, mouseover, mousemove, click)
  - Keyboard events (keydown, keypress, keyup)
  - State events (load, unload, abort, error)
  - Mutation events (reacts on modifications of the DOM tree, e.g. DOMNodeInserted)
  - SMIL animation events (reacts on different states in SMIL animation, beginEvent, endEvent, repeatEvent)
  - UI events (focusin, focusout, activate)
  - SVG specific events (SVGZoom, SVGScroll, SVGResize)
- Network requests – This is necessary to load additional data and content into a web page. Most modern browsers provide the XMLHttpRequest object which allows for get and post http requests and provides some feedback on the data loading state. The data received can be processed by ECMAScript and can be included into the current DOM tree of the web page / web map. SVG user agents alternatively provide the getURL and postURL methods for network requests. It is recommended to test for the existence of a network request method and provide alternatives if one method isn't present. As an example, a wrapper function could handle the network requests and test whether XMLHttpRequests or getURL or alternative methods are available and choose the best one available. These network requests are also known under the term Ajax
  Ajax (programming)
  Ajax is a group of interrelated web development methods used on the client-side to create asynchronous web applications...
  
  .
- DOM support – The Document Object Model
  Document Object Model
  The Document Object Model is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents. Aspects of the DOM may be addressed and manipulated within the syntax of the programming language in use...
  
  provides a language independent API for the manipulation of the document tree of the webpage. It exposes properties of the individual nodes of the document tree, allows to insert new nodes, delete nodes, reorder nodes and change existing nodes. DOM support is included in any modern web browser. DOM support together with scripting is also known as DHTML or Dynamic HTML. Google Maps
  Google Maps
  Google Maps is a web mapping service application and technology provided by Google, free , that powers many map-based services, including the Google Maps website, Google Ride Finder, Google Transit, and maps embedded on third-party websites via the Google Maps API...
  
  and many other web mapping sites use a combination of DHTML, Ajax, SVG and VML.
- SVG support or SVG image support – SVG is the abbreviation of "Scalable Vector Graphics" and integrates vector graphics, raster graphics and text. SVG also supports animation, internationalization, interactivity, scripting and XML based extension mechanisms. SVG is a huge step forward when it comes to delivering high quality, interactive maps. At the time of writing (2007–01), SVG is natively supported in Mozilla/Firefox >version 1.5, Opera >version 9 and the developer version of Safari/Webkit. Internet Explorer users still need the Adobe SVG viewer plugin provided by Adobe. For a German book on web mapping with SVG see and for an English paper on SVG mapping see.
- Java support – some browsers still provide old versions of the Java virtual machine. An alternative is the use of the Sun Java Plugin. Java is a full featured programming language that can be used to create very sophisticated and interactive web maps. The Java2D and Java3D libraries provide 2d and 3d vector graphics support. The creation of Java based web maps requires a lot of programming know how. Adrian Herzog discusses the use of Java applets for the presentation of interactive choroplethe and cartogram maps.
- Web browser plugins
  - Adobe Acrobat
    Adobe Acrobat
    Adobe Acrobat is a family of application software developed by Adobe Systems to view, create, manipulate, print and manage files in Portable Document Format . All members of the family, except Adobe Reader , are commercial software, while the latter is available as freeware and can be downloaded...
    
    – provides vector graphics and high quality printing support. Allows toggling of map layers, hyper links, multimedia embedding, some basic interactivity and scripting (ECMAScript).
  - Adobe Flash – provides vector graphics, animation and multimedia support. Allows the creation of sophisticated interactive maps, as with Java and SVG. Features a programming language (ActionScript) which is similar to ECMAScript. Supports Audio and Video.
  - Apple Quicktime – Adds support for additional image formats, video, audio and Quicktime VR (Panorama Images). Only available to Mac OS X and Windows.
  - Adobe SVG viewer – provide SVG 1.0 support for web browsers, only required for Internet Explorer Users, because it doesn't yet natively support SVG. The Adobe SVG viewer isn't developed any further and only fills the gap until Internet Explorer gains native SVG support.
  - Sun Java plugin provides support for newer and advanced Java Features.

External links

Sites

Networks

Open Forum on Participatory Geographic Information Systems and Technologies - a global network of PGIS/PPGIS practitioners with Spanish, Portuguese and French-speaking chapters.
Geowanking

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.