ENVIGridDefinition::CreateGridFromCoordSys

This function method returns a new grid definition with the same spatial extent as the original but in a different coordinate system. It preserves the spatial extent, rows, and columns from the original grid. Use this method to reproject a raster to a new coordinate system.

Example

; Start the application

e = ENVI()

; Select input data

file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $

  SUBDIRECTORY = ['data'])

raster = e.OpenRaster(file)

; Retrieve the grid parameters of the raster

PixelSize = raster.SPATIALREF.PIXEL_SIZE

CoordSysString = raster.SPATIALREF.COORD_SYS_STR

NumRows = raster.NROWS

NumCols = raster.NCOLUMNS

TiePointMap = raster.SPATIALREF.TIE_POINT_MAP

TiePointPixel = raster.SPATIALREF.TIE_POINT_PIXEL

CoordSys = ENVICoordSys(COORD_SYS_STR=CoordSysString)

; Create a grid definition for the original raster

GridDefGeo = ENVIGridDefinition(CoordSys, $

  PIXEL_SIZE=PixelSize, $

  NROWS=NumRows, $

  NCOLUMNS=NumCols, $

  TIE_POINT_MAP=TiePointMap, $

  TIE_POINT_PIXEL=TiePointPixel)

; Convert the grid to a UTM projection

UTMCoordSys = ENVICoordSys(COORD_SYS_CODE=32611)

GridDefUTM = GridDefGeo.CreateGridFromCoordSys(UTMCoordSys)

ReprojectedRaster = ENVISpatialGridRaster(raster, $

  GRID_DEFINITION=GridDefUTM)

; Display the reprojected raster

View = e.GetView()

Layer = View.CreateLayer(ReprojectedRaster)

Syntax

Result = ENVIGridDefinition.CreateGridFromCoordSys(CoordSys)

Arguments

CoordSys

Specify an ENVICoordSys object indicating the coordinate system that the raster will reproject to.

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 5.2

Introduced