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ENVICoordSys::ConvertMapToLonLat

ENVICoordSys::ConvertMapToLonLat

The ConvertMapToLonLat method converts a set of map coordinates (x-eastings, y-northings) to a set of latitude/longitude coordinates within the same coordinate system.

Example


The following example converts a set of map coordinates in a vector file to lon/lat coordinates.

; Launch the application
e = ENVI(/HEADLESS)
 
file = FILEPATH('qb_boulder_msi_vectors.shp', $
  SUBDIRECTORY = ['data'], ROOT_DIR=e.Root_Dir)
 
; Create an ENVIVector from the shapefile data
vector = e.OpenVector(file)
 
; Retrieve a reference to the coordinate system
VectCoords=vector.COORD_SYS
 
; Provide a set of map coordinates
MapX = 482186.3200D
MapY = 4428133.6400D
 
VectCoords.ConvertMapToLonLat, MapX, MapY, Lon, Lat
PRINT, 'Map coordinates: ',MapX, MapY
PRINT, 'Lon/Lat coordinates: ',Lon, Lat

Syntax


ENVICoordSys.ConvertMapToLonLat, MapX, MapY, Lon, Lat

Arguments


MapX

The map x-coordinate (easting). You can specify a scalar or a vector of MapX values; if it is a vector, the MapY argument should also be a vector with the same number of elements:

MapX = [481874.4000D, 482260.8000D]
MapY = [4428160.8000D, 4427992.8000D]

MapY

The map y-coordinate (northing)

Lon

A named variable that contains the longitude value

Lat

A named variable that contains the latitude value

Keywords


ERROR

Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.

When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.

See Manage Errors for more information on error handling in ENVI programming.

Version History


ENVI 5.1

Introduced

API Version


3.2

See Also


ENVICoordSys, ENVICoordSys::ConvertLonLatToMap



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