The ConvertFileToLonLat method converts a set of pixel (x,y) coordinates in a standard spatial reference to a set of geographic latitude and longitude coordinates within the same spatial reference.


; Launch the application
; Open a file with a standard spatial reference
file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $
   SUBDIRECTORY = ['data'])
; Get the spatial reference
raster = e.OpenRaster(file)
spatialRef = raster.spatialRef
; Provide a set of file coordinates
FileX = 685.0
FileY = 301.0
; Convert file coordinates to lat/lon
spatialRef.ConvertFileToLonLat, FileX, FileY, Lon, Lat
PRINT, 'Latitude: ', Lat
PRINT, 'Longitude: ', Lon


ENVIStandardRasterSpatialRef.ConvertFileToLonLat, FileX, FileY, Lon, Lat



The file X-coordinate. You can specify a scalar or a vector of FileX values; if it is a vector, the FileY argument should also be a vector with the same number of elements:

FileX = [688.0, 641.1]
FileY = [301.0, 280.0]


The file Y-coordinate


A named variable that will contain the geographic longitude


A named variable that will contain the geographic latitude



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 5.6.1


API Version


See Also

ENVIStandardRasterSpatialRef, ENVIRPCRasterSpatialRef::ConvertFileToLonLat, ENVIPseudoRasterSpatialRef::ConvertFileToLonLat