ENVIROI::AddPixels

The AddPixels method adds pixels to an ROI.

Example

For the following example:

Copy and paste the procedure into an IDL editor window.
Save the file as enviroi_addpixels_example.pro.
Compile and run the procedure.

PRO enviroi_addpixels_example

compile_opt idl2

; Launch the application

e = ENVI()

; Create an ROI

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

  SUBDIRECTORY = ['data'])

raster = e.OpenRaster(file)

view = e.GetView()

layer = view.CreateLayer(raster)

roi1 = ENVIROI(NAME='Sun Reflectance', COLOR='Red')

; Iterate through the tiles of the data set

tileIterator = raster.CreateTileIterator()

FOREACH data, tileIterator DO BEGIN

ptr = WHERE(DATA GT 1000 AND data LT 1530, COUNT)

  IF (COUNT GT 0) THEN BEGIN

    x = (tileIterator.Current_Subrect)[0] + $

        (ptr mod (tileIterator.Tile_Size)[0])

    y = (tileIterator.Current_Subrect)[1] + $

        (ptr / (tileIterator.Tile_Size)[0])

    roi1.AddPixels, Transpose([[x],[y]]), spatialref=raster.spatialref

  ENDIF

ENDFOREACH

visRoi1 = layer.AddRoi(roi1)

END

Syntax

ENVIROI.AddPixels, Data [, Keywords=value]

Arguments

Data

A 2 x n array that defines the 2-D vertex data. This data is stored as a 64-bit long integer.

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.

SPATIALREF

Set the ENVIRaster reference that establishes the coordinate system reference for the pixel locations contained in the data. This keyword is not required; however, if it is not specified, ENVI will be unable to reproject the ROI pixels correctly.

Version History

ENVI 5.1

Introduced

API Version

4.2