They are mainly concerned with the spatial data. Format Transformations Format is the pattern into which data are systematically arranged for use on a computer. Format transformations are used to get data into acceptable GIS format. Digital Files must be transformed into the data format used by the GIS, such as transforming from raster to vector data structure. A raster data often requires no re-formatting.
Transformation can be very costly and time-consuming with poor coordinate data.
Geometric Transformations 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 . Relative Position refers to the location of features in relation to a geographic coordinate system. It needs easily identifiable, accurate, well distributed control points. Absolute Position is the location in relation to the ground.