Global Mapper v25.0

How to remove black regions in exported ECW image...


I exported some JPEG2000 imagery to ECW. The original imagery contained some black regions that I was hoping would be removed in the ECW export process since I selected the option to "Make Background (Void) Pixels Transparent" in the "ECW Export Options". Unfortunately, that did not work to get rid of the black.

Is there another way to remove black regions in the exported ECW raster?

Thanks in advance...



  • I forgot to mention that I'm using GlobalMapper v23.0

  • Create an area along the borders of the raster. No black bits. When exporting, please specify:

  • The option to Make Background (Void) Pixels Transparent wouldn't work in your case because the areas are black and not transparent.

    You could create a polygon to define the boundary and use it to crop the image using the Cropping tab (Crop to currently selected polygon(s).

    Or you can create polygons to remove areas using the Cropping tab (Cut out currently selected polygons(s).

    To make specific colour transparent for a raster layer do the following:

    1. Open the layers Options (double-click the layer)
    2. Go to the Display tab
    3. Check Transparent
    4. Click on Set Transparent Color
    5. Click Pick from Map
    6. Pick the black colour from the image with the eyedropper
    7. Hit Apply
    8. If there is any remaining black move the slider between Exact and Fuzzy and Apply again until you get the result you want

    Be careful it doesn't remove similar colours from your image.