ENVI::OpenROI

The OpenROI function method opens an existing ROI file (.roi or .xml) and returns an array of ENVIROI objects.

Example

; Launch the application

e = ENVI()

; open and display qb_boulder_msi

file = Filepath('qb_boulder_msi', ROOT_DIR=e.Root_Dir, $

SUBDIRECTORY=['data'])

raster = e.OpenRaster(file)

view = e.GetView()

layer = view.CreateLayer(raster)

; open and display the ROIs from qb_boulder_roi

file = Filepath('qb_boulder_roi.xml', ROOT_DIR=e.Root_Dir, $

SUBDIRECTORY=['data'])

rois = e.OpenRoi(file)

numRois = N_Elements(rois)

roiLayers = Objarr(numRois)

FOR i=0, N_Elements(rois)-1 DO $

roiLayers[i] = layer.AddRoi(rois[i])

Syntax

Result = ENVI.OpenRoi(URI [, Keywords=value])

Return Value

This method returns an array of ENVIROI references.

Arguments

URI

A scalar string that is a fully-qualified ROI file path.

Keywords

Keywords are applied only during the initial creation of the object.

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.

PARENT_RASTER

This keyword only applies to ENVI Classic .roi files. If opening a .roi file, set this keyword to an ENVIRaster reference to specify the parent raster from which the ENVI Classic ROI pixels originated. This keyword is not required when opening an .roi file; however, if it is not specified, ENVI will be unable to reproject the ROI pixels correctly when they are overlaid on images that have different pixel sizes and/or projections than the original source raster.

Version History

ENVI 5.1

Introduced

API Version

4.2