Rubbersheeting
Encyclopedia
In cartography
, rubber-sheeting refers to the process by which a layer is distorted to allow it to be seamlessly joined to an adjacent geographic layer of matching imagery, such as satellite
imagery (most commonly vector cartographic data) which are digital maps. This is sometimes referred to as image-to-vector conflation
. Often this has to be done when layers created from adjacent map sheets are joined together. Rubber-sheeting is necessary because the imagery and the vector data will rarely match up correctly due to various reasons, such as the angle at which the image was taken, the curvature
of the surface of the earth, minor movements in the imaging platform (such as a satellite
or aircraft
), and other errors in the imagery.
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...
, rubber-sheeting refers to the process by which a layer is distorted to allow it to be seamlessly joined to an adjacent geographic layer of matching imagery, such as satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
imagery (most commonly vector cartographic data) which are digital maps. This is sometimes referred to as image-to-vector conflation
Conflation
Conflation occurs when the identities of two or more individuals, concepts, or places, sharing some characteristics of one another, become confused until there seems to be only a single identity — the differences appear to become lost...
. Often this has to be done when layers created from adjacent map sheets are joined together. Rubber-sheeting is necessary because the imagery and the vector data will rarely match up correctly due to various reasons, such as the angle at which the image was taken, the curvature
Curvature
In mathematics, curvature refers to any of a number of loosely related concepts in different areas of geometry. Intuitively, curvature is the amount by which a geometric object deviates from being flat, or straight in the case of a line, but this is defined in different ways depending on the context...
of the surface of the earth, minor movements in the imaging platform (such as a satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
or aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
), and other errors in the imagery.
Applications in history and historical geography
Rubber-sheeting is a useful technique in Historical GIS, where it is used to digitize and add old maps as feature layers in a modern GIS. Before aerial photography arrived, most maps were highly inaccurate by modern standards. Rubber-sheeting may improve the value of such sources and make them easier to compare to modern maps.Software for Rubber-sheeting
- ESRI'sESRIEsri is a software development and services company providing Geographic Information System software and geodatabase management applications. The headquarters of Esri is in Redlands, California....
ArcGISArcGISArcGIS is a suite consisting of a group of geographic information system software products produced by Esri.ArcGIS is a system for working with maps and geographic information...
8.3+ has the capability of rubber-sheeting vector dataVector graphicsVector 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...
, and ArcMap 9.2+ may also rubber-sheet raster layersRaster graphicsIn 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...
. - AutoCAD'sAutoCADAutoCAD is a software application for computer-aided design and drafting in both 2D and 3D. It is developed and sold by Autodesk, Inc. First released in December 1982, AutoCAD was one of the first CAD programs to run on personal computers, notably the IBM PC...
Land Desktop allows a user to rubber sheet raster dataRaster graphicsIn 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...
.