[Geotools-gt2-users] How to make use of ROI parameter for JAI operations?

[Tobias Gerdin]

Hello,

I am trying to make use of the ”Rescale” GT operation with a ROI (a ROIShape). 
However, as soon as I specify a “ROI” parameter (with or without the 
“useRoiAccessor” parameter) the resulting GridCoverage is just zero. I do not 
specify any NoData parameter. When not specifying the ROI parameters the 
operation works as expected.

I make use of the CoverageProcessor like so:

    CoverageProcessor processor = CoverageProcessor.getInstance();
    var params = processor.getOperation("Rescale").getParameters();
    params.parameter("Source").setValue(coverage);

    var multipliers = new double[coverage.getNumSampleDimensions()];
    var offsets = new double[coverage.getNumSampleDimensions()];
    for (int i=0; i<multipliers.length;i++) {
        multipliers[i] = 1.0;
        offsets[i] = 0.0;
    }
    multipliers[2] = 1.1; // increase values in ROI in band 2 by 10%
    params.parameter("constants").setValue(multipliers);
    params.parameter("offsets").setValue(offsets);

    Geometry targetRoi = JTS.transform(roi, transform); // reproject roi 
geometry to coverage CRS
    var shape = new LiteShape(targetRoi, 
(AffineTransform)gridGeometry.getCRSToGrid2D(), false);
    ROI roi = new ROIShape(shape);
    params.parameter("ROI").setValue(roi);
    params.parameter("useRoiAccessor").setValue(true);

    GridCoverage2D changed = (GridCoverage2D)processor.doOperation(params);

I noticed that the first argument to handleROINoDataProperties at 
https://github.com/geotools/geotools/blob/d8d3fa7bc5a33d0f93a84ab6c51bec852cfe47cf/modules/library/coverage/src/main/java/org/geotools/coverage/processing/operation/Rescale.java#L121
Is set to null, which seems to cause getProperties to return an empty map. This 
does not seem right.

Is ROI not supposed be supported for this operation?

I am using Geotools 22.3 with Maven on Windows 10.

Regards,

Tobias Gerdin

Havs- och vattenmyndigheten behandlar dina personuppgifter i enlighet med 
dataskyddsförordningen och myndighetens dataskyddspolicy, läs mer på 
www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter<https://www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter>
SwAM processes your personal data in accordance with the General Data 
Protection Regulation (GDPR) and our Data Protection Policy, see 
www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter<https://www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter>

_______________________________________________
GeoTools-GT2-Users mailing list
GeoTools-GT2-Users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users