The MAP_PROJ_INFO procedure returns information about the current map and/or the available projections.
Note: The MAP_PROJ_INFO procedure is compiled along with the MAP_SET procedure. You must call the MAP_SET Procedure procedure to set up mapping parameters before calling MAP_PROJ_INFO.
This routine is written in the IDL language. Its source code can be found in map_proj_info.pro in the lib subdirectory of the IDL distribution.
MAP_PROJ_INFO [, iproj] [, AZIMUTHAL=variable] [, CIRCLE=variable] [, CYLINDRICAL=variable] [, /CURRENT] [, LL_LIMITS=variable] [, NAME=variable] [, PROJ_NAMES=variable] [, UV_LIMITS=variable] [, UV_RANGE=variable]
The projection index. If the CURRENT keyword is set, then the index of the current map projection is returned in Iproj.
Set this keyword to a named variable that, upon return, will be set to 1 if the projection is azimuthal and 0 otherwise.
Set this keyword to a named variable that, upon return, will be set to 1 if the projection is circular or elliptical and 0 otherwise.
Set this keyword to use the current projection index and return that index in Iproj.
Set this keyword to a named variable that, upon return, will be set to 1 if the projection is cylindrical and 0 otherwise.
Set this keyword to a named variable that will contain the geocoordinate rectangle of the current map in degrees, [Latmin, Lonmin, Latmax, Lonmax]. This range may not always be available, especially if the LIMIT keyword was not specified in the call to MAP_SET. If either or both the longitude and latitude range are not available, the minimum and maximum values will be set to zero.
Set this keyword to a named variable that will contain the name of the projection.
Set this keyword to a named variable that will contain a string array containing the names of the available projections, ordered by their indices. The first projection name is stored in element one.
Set this keyword to a named variable that will contain the UV bounding box of the current map, [Umin, Vmin, Umax, Vmax].
Set this keyword to a named variable that will contain the UV coordinate limits of the selected map projection, [Umin, Vmin, Umax, Vmax]. UV coordinates are mapped to normalized coordinates using the system variables !X.S and !Y.S. These limits are dependent upon the selected projection, but independent of the current map.
; Establish a projection
MAP_SET, /MERCATOR
;Obtain projection characteristics
MAP_PROJ_INFO, /CURRENT, NAME=name, AZIMUTHAL=az, $
CYLINDRICAL=cyl, CIRCLE=cir
On return, the variables will be set as follows:
AZ INT = 0
CIR INT = 0
CYL INT = 1
NAME STRING 'Mercator'
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5.0 |
Introduced |