mask by image resizes the image to size of mask image

[Girish Kumar]

Dear all,

        I want to mask out waterbodies from NDVI image. The mask function does the masking, but the resultant image has been resized to the size of mask image. I want to retian the size of output image as same as the size of input image, since the size of mask image is smaller.

With warm regards

Girish

[Daniel Clewley]

Hi Girish,

You can’t do this using the mask function within RSGISLib as most of the functions apply only to the overlapping area of input images.

One way of getting round this it to pad the mask image so it is the same extent as your image using the resampleImage2Match function ( http://rsgislib.org/rsgislib_imageutils.html#rsgislib.imageutils.resampleImage2Match) 

Another option is to do this in RIOS by setting the bounds to the input image rather than the mask using:

    controls.setReferenceImage(input_image)
    controls.setFootprintType("BOUNDS_FROM_RERERENCE")

For more details on RIOS see http://rioshome.org/en/latest/ and https://spectraldifferences.wordpress.com/tag/rios/

Thanks,

Dan

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[Pete Bunting [pfb]]

Hi Girish,

As Dan said you’re best bet is to pan the mask you want to apply. If the mask is a different projection and/or pixel size to your image then the command Dan suggests would work well.

If they are already on the same pixel grid then I would use rsgislib.imageutils.createCopyImage to create an image the same size of the image you want to mask and then use rsgislib.imageutils.includeImages to add your mask to the new image.

Best wishes,

Pete

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[Girish Kumar]

Dear Dan,

           Thank you for the suggestion. I have tried it and it is working fine.

[Girish Kumar]

Dear Pete,

    Thank you for giving the suggestion. I have tried the suggestion by Dan and it is working fine.