The ConvertLonLatToFile method converts a set of geographic latitude/longitude coordinates in a standard spatial reference to file coordinates within the same spatial reference.

Example


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

; Launch the application
e = ENVI(/HEADLESS)
 
; Open a file with a standard spatial reference
file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $
  SUBDIRECTORY = ['data'])
raster = e.OpenRaster(file)
 
; Get the spatial reference
spatialRef = raster.spatialRef
 
; Provide a set of lon/lat coordinates
Lon = -105.2212463D
Lat = 40D
 
; Convert to file coordinates
spatialRef.ConvertLonLatToFile, Lon, Lat, FileX, FileY
PRINT, 'Lon/Lat coordinates: ',Lon, Lat
PRINT, 'Map coordinates: ',FileX, FileY

Syntax


ENVIStandardRasterSpatialRef.ConvertLonLatToFile, Lon, Lat, FileX, FileY

Arguments


Lon

The longitude coordinate. You can specify a scalar or a vector of longitude values; if it is a vector, the Lat argument should also be a vector with the same number of elements; for example:

Lon = [-123.58, -134.64]
Lat = [48.23, 49.56]

Lat

The latitude coordinate

FileX

A named variable that contains the pixel x-coordinate

FileY

A named variable that contains the pixel y-coordinate

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 5.6.1

Introduced

API Version


4.3

See Also


ENVIStandardRasterSpatialRef, ENVIPseudoRasterSpatialRef::ConvertLonLatToFile, ENVIRPCRasterSpatialRef::ConvertLonLatToFile