ENVIStandardRasterSpatialRef::ConvertLonLatToFile

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

4.2