Glossary for Geospatial Science

georeference or geographic calibration:  Information that relates raster cells or vector/CAD elements to a specified coordinate system or map projection.  The RVC file format keeps the information needed to relate every raster cell or vector coordinate point to some geographic coordinate system (like a particular map projection) in subobjects associated with the parent object.  Geographic calibration may be established when creating an object (like extracting an image map from a Landsat or SPOT satellite image).  Calibration can also be added to an existing object either by entering control points or by associating it with some calibrated object (like overlaying a calibrated vector to calibrate a raster).  An RVC subobject identifies a calibrated object’s map projection.