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I am working with Landsat 8 in ENVI. My image's dimensions are 8921 x 13131. I need to apply a forest mask to this image with dimensions of 8805 x 12321. I try to resize an image, but it doesn't work. (After that I need to calculate forest disturbance index for 2013 and subtract it from DI for 2000, so I really need an 2013 image (Landsat 8) to be resized).

I resize it using basic tool - spatial subset - subset using - file - and then pick my forest mask. However, as a result I get a file of 8806 x 12321 instead of 8805. If I adjust the number of samples manually, it gives me 8805. But then I try to apply a mask and that's what I get (see a screenshot). They just don't match. And when I try to overlay my mask (which I made based on Landsat 7 image) with my Landsat 8 image, those two images have different frames.

Does anybody have any good advice?

enter image description here

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The extents are not exactly the same but this is normal. you should not change the number of pixels by changing their size (what resize does) but by changing the extent using subset by file (or by ROI if you want to have the minimum extent of the two images).

  • Thank you for your reply. I tried using subset by file, it gives me 8806 samples instead of 8805. And then ENVI doesn't allow to mask a 8806 file with 8805 mask :( – Lybica Mar 27 '14 at 14:35
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You may compare Landsat imagery and analyze it with ease via LandViewer. There are dozens of built-in tools available for image analysis and compare thousands of images with ease. Here’s a brief guide to free satellite data that can be found on LandViewer

  • Landsat 4 - archive 1982-1993
  • Landsat 5 - archive 1984-2013
  • Landsat 7 - archive since 1999
  • MODIS - archive since 2012
  • Landsat 8 - archive since 2013
  • Sentinel-1 - archive since 2014
  • Sentinel-2 - archive since 2015

An example of such imagery can be seen HERE.

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It can be done by changing the mask to ROI and using the tool "reconcile ROIs" to match the mask and landsat 8 image.

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