Glossary for Geospatial Science

nominal image map:� A preliminary map form that approximates an image map and that can usually be prepared using fully automated procedures.� For example, TNTmips can automatically extract a 7.5' nominal image map from Landsat or SPOT satellite images using the positional and angular properties provided with the images.� However, to convert it to an accurate image map, the user must introduce ground control points.

A topographic map that has been scanned (but not yet calibrated) is another example of a nominal image map.� Similarly, using TNTmips to mosaic airslides or airvideo images that cover the area of a 7.5' map provides a nominal image map. (By contrast, rectifying and assembling these source images yields an image map, since that process used ground control points in some map coordinates.) (See also: image map.)