geometric transformation - [coordinate systems] The process of rectifying a raster dataset to map coordinates or converting a raster dataset from one coordinate system to another. [Category=Geospatial ] ...
This function is concerned with the registering of a data layer to a common coordinate scheme. This usually involves registering selected data layers to a standard data layer already registered. The term rubber sheeting is often used to describe this function.
Geometric transformations are used to assign ground coordinates to a map or data layer within the GIS or to adjust one data layer so it can be correctly overlayed on another of the same area. The procedure used to accomplish this correction is termed registration.
A geometric transformation that scales, rotates, or translates images or coordinates between any two Euclidean spaces. It is commonly used in GIS to transform maps between coordinate systems. In a Helmert transformation, parallel lines remain parallel.
The geometric transformations that arise during map reprojection efforts can cause problems for raster graphics and represent a third disadvantage to using the raster data model.
2.1 Common Geometric Transformations
3 Additional Features
4 Spatial ETL Uses
5 Spatial ETL - Origins and History
6 Spatial ETL and GIS
7 Spatial ETL and ETL
8 Spatial ETL tools
9 See also ...
The grouping of observations into control and check points is useful for estimating the relative accuracy of the geometric transformations. This measure of accuracy is relative to how well the distortions have been sampled while it also reflects the adequacy of the model for these points.
This is an error measurement that most GIS report during geometric transformation of data sets. It is mathematically the spatial equivalent to the standard deviation.
Perhaps the most frequent geometric transformation is the conversion of lines to polygons. This happens a lot because many CAD programs often use line segments to build parcels (and other features), but within a GIS these features are best coded as polygons.
[Euclidean geometry] A geometric transformation that scales, rotates, skews, and/or translates images or coordinates between any two Euclidean spaces. It is commonly used in GIS to transform maps between coordinate systems.
Much more functionality is accessible via Avenue, such as hydrological analysis and geometric transformations, just to name a few. Search the on-line help index on "grid" to find the Grid (Class) topic to find out all the functionality available through Avenue for the Spatial Analyst.
The image warp and registration function has added options to use either bi-linear or triangulation for more accurate image geometric transformation based on control point selection.
Geometric transformations are procedures used to ensure that each data layer precisely overlays the other data layers. Some data may be supplied in geometric coordinates (latitude and longitude), whereas other data may be supplied in UTM or state plane coordinates.
For the other years, there is apparently no land area column, but it appears that the inundated areas have been removed from each tract. It is possible to calculate the area for each polygon in ArcGIS. watch for a future web page on geometric transformations for tips on how to do this.
See also: What is the meaning of Transformation, Transform, Information, Image, GIS?