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ENVITiePointSet::Scale

ENVITiePointSet::Scale

The Scale function method scales the pixel coordinates of all tie points in an ENVITiePointSet object. Use this method when applying tie points from a down-sampled image as seed tie points to the full-resolution image.

Example


This example uses a sample auto-generated tie point file that was created by choosing the default options in the Image Registration workflow, using two input images quickbird_2.4m.dat and ikonos_4.0m.dat. The sample tie point file (SampleTiePoints.pts) and images are available on the ENVI Resource DVD under the /image_reg directory or from the ENVI Tutorials web page. Click the "ENVI Tutorial Data" hyperlink. Copy the files to your local drive. Then edit SampleTiePoints.pts to include the full path to the sample images quickbird_2.4m.dat and ikonos_4.0m.dat.

; Start the application
e = ENVI()
 
; Open an existing tie point file
tiePointFile = 'SampleTiePoints.pts'
tiePoints = ENVITiePointSet(tiePointFile)
 
; Scale the image
scaledPoints = tiePoints.Scale(2.0, 2.0, 1.0, 1.0)
 
; Create a new ENVITiePointSet object
newTiePoints = ENVITiePointSet(TIEPOINTS=scaledPoints, $
  INPUT_RASTER1=tiePoints.INPUT_RASTER1, $
  INPUT_RASTER2=tiePoints.INPUT_RASTER2)
 

Syntax


Result = ENVITiePointSet.Scale(Column1Scale, Row1Scale, Column2Scale, Row2Scale [, ERROR=variable])

Return Value


This method returns the scaled pixel coordinates of all tie points in an ENVITiePointSet object.

Arguments


Column1Scale

Specify the Column1 scale factor in the first input image. The new Column1 coordinate will be the original Column1 value multiplied by Column1Scale. If no scaling is preferred, enter a value of 1.0.

Row1Scale

Specify the Row1 scale factor in the first input image. The new Row1 coordinate will be the original Row1 value multiplied by Row1Scale. If no scaling is preferred, enter a value of 1.0.

Column2Scale

Specify the scale factor to apply to Column2 of the second input image. If no scaling is preferred, enter a value of 1.0.

Row2Scale

Specify the scale factor to apply to Row2 of the second input image. If no scaling is preferred, enter a value of 1.0.

Keywords


ERROR (optional)

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, Service Pack 1

Introduced

API Version


3.3

See Also


ENVITiePointSet



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