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ENVI_GET_MAP_INFO

ENVI_GET_MAP_INFO

This routine has been replaced with the COORD_SYS_CODE and COORD_SYS_STR properties to ENVIRasterSpatialRefStandard, for standard map projections. For non-standard map projections, see ENVIRasterSpatialRefPseudo or ENVIRasterSpatialRefRPC.

Use this function to return a map information structure for the specified file or display group. If there is no map information associated with the FID or DN, then the UNDEFINED keyword returns a value of 1. The result of this function can be used for other functions that require an input MAP_INFO structure, such as ENVI_SETUP_HEAD.

Syntax


Result = ENVI_GET_MAP_INFO([, DN=integer] [, FID=file ID] [, UNDEFINED=variable])

Keywords


DN (optional)

This keyword cannot be used to reference the ENVI display. It is only for use with ENVI Classic display groups.

Use this keyword to specify the display number for the returned projection information. The function will return the map information structure for the data in the display group. If the displayed data are not georeferenced, an Arbitrary projection is returned.

Display numbers (DNs) are zero-based; ENVI Classic Display #1 corresponds to DN=0. You can retrieve DNs in the event handler of user-managed display events. For example, use the following code to retrieve the uvalue for ev.top:

widget_control, ev.top, get_uvalue=dn

FID (optional)

Use this keyword to specify the file ID for the returned map information. If the file is not georeferenced, an Arbitrary projection is returned. This value is returned from the keyword R_FID in the ENVI_OPEN_FILE procedure. FID is a long integer with a value greater than 0. An invalid file ID has a value of -1.

UNDEFINED (optional)

Set this keyword to a named variable that contains either 0 or 1. A value of 0 indicates the returned projection is valid. A value of 1 indicates no projection exists for the given DN or FID, and the resulting map information structure is invalid.



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