Use this keyword to specify the datum for the map information projection. A map-based projection uses the lower-left corner of the image as the projection origin, while a pixel-based projection (non-map based) uses the upper-left corner as the origin. The default is a non-map based projection. Set the keyword MAP_BASED to create a map-based projection. Set this keyword to create an Arbitrary projection for the map information. Result = ENVI_MAP_INFO_CREATE(, MC= array, PS= array ) Keywords Note: Use this function instead of accessing the map information structure directly. For example, to georeference an image, ENVI_SETUP_HEAD requires an input MAP_INFO structure.

The result of this function can be used for functions that require an input MAP_INFO structure. With optional keywords, you can define the datum, name, units, projection parameters, pixel size, rotation, and map coordinates. You can define projections using the procedure ENVI_PROJ_CREATE. All other projections use the PROJ keyword to define the associated projection. Arbitrary, Geographic, UTM, and State Plane map information structures use their corresponding keyword. This function returns an ENVI Classic map information structure for any of the supported map projections.

This routine is obsolete and has been replaced with one of the following objects, depending on the type of spatial reference (standard, RPC, or pseudo):

Utm zone map