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Techniques to map small water bodies in desert

I have task to map water bodies in a desert. I used landsat 8 and calculated three indices called NDMI, Tasseled Cap Wetness, & AWEIsh. I am unable to map outlines water bodies as those appear in satellite view of GEE. Screenshot, kml file and code link attached. I used threshold values from literature even Ostu segmentation to find optimal threshold.

What I should do to get map water bodies along with their natural boundaries? Unmixing? High spatial resolution data? Other image classification technique? use https://imagej.nih.gov/ij/plugins/versatile-wand-tool/index.html
https://code.earthengine.google.com/93ceae78cac565d6f8975da1aff1c370enter image description here

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  • What area of the world is your area of interest? I agree with @JonasV in that you need higher spatial resolution data. Have you looked at Planet imagery? If in the US, you can use NAIP imagery.
    – Aaron ♦
    May 26 '20 at 13:41
  • Thanks , my study area is cholistan desert in Pakistan.
    – Tariq Abbas
    May 26 '20 at 14:38
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You need much higher resolution data if you want to map the corners more sharply. Those ponds are about 60 m wide. With Landsat 8s resolution of 30 m per pixel you will get 3-4 pixels per pond like in the image.

If you want to stay with free imagery you can try Sentinel 2. It has 4 Bands with a resolution of 10 m. For very high resolution data you would most likely have to pay (Planetscope, Pleiades, etc.).

Another option in a completely different direction might be SAR data, by Sentinel 1 for example. But the resolution will not be much better than Sentinel 2.

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