The ConvertMapToFile method converts the following within a standard spatial reference:
- Geographic coordinates (x=longitude, y=latitude) to file (pixel) x,y coordinates
- Projected coordinates (x=eastings, y=northings) in linear units to file (pixel) x,y coordinates
Example
The following example converts a set of projected coordinates to file coordinates within the same spatial reference.
e = ENVI(/HEADLESS)
file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $
SUBDIRECTORY = ['data'])
raster = e.OpenRaster(file)
spatialRef = raster.spatialRef
MapX = 481874.4000D
MapY = 4428160.8000D
spatialRef.ConvertMapToFile, MapX, MapY, FileX, FileY
PRINT, 'Map coordinates: ',MapX, MapY
PRINT, 'File coordinates: ',FileX, FileY
The next example converts a set of geographic (latitude/longitude) coordinates to file coordinates within the same spatial reference.
e = ENVI(/HEADLESS)
file = FILEPATH('GMTED2010.jp2', ROOT_DIR=e.ROOT_DIR, $
SUBDIRECTORY = ['data'])
raster = e.OpenRaster(file)
spatialRef = raster.spatialRef
MapX = 72.0D
MapY = 35.0D
spatialRef.ConvertMapToFile, MapX, MapY, FileX, FileY
PRINT, 'Map coordinates: ',MapX, MapY
PRINT, 'File coordinates: ',FileX, FileY
Syntax
ENVIStandardRasterSpatialRef.ConvertMapToFile, MapX, MapY, FileX, FileY
Arguments
MapX
For a projected coordinate system, specify the x-coordinate (easting) in meters or feet. 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]
For a geographic coordinate system, specify the x-coordinate (longitude) in decimal degrees. 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 = [-112.0D, -83.0D]
MayY = [-39.0D, -37.0D]
MapY
For a projected coordinate system, specify the y-coordinate (northing) in meters or feet. For a geographic coordinate system, specify the y-coordinate (latitude) in decimal degrees.
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
API Version
4.3
See Also
ENVIStandardRasterSpatialRef, ENVIPseudoRasterSpatialRef::ConvertMapToFile, ENVIRPCRasterSpatialRef::ConvertMapToFile