enter image description hereHow to overcome No Data in ALOS DEM which acquired at location of Ernakulam, Kerala. Attached .JPG screen shot of my screen.

Why it is showing NODATA??


Judging from the filenames in the screen provided, you are not using ALOS DEM but SRTM data that accompany ASF ALOS RTC products. Despite a widespread misconception, those are not ALOS DEM but up-sampled SRTM elevation tiles, 30m original resolution, used for terrain correction in ALOS radar images by the ASF. 12.5m resolution is only for the product raster file not original data. https://media.asf.alaska.edu/uploads/RTC/rtc_product_guide_v1.2.pdf

So you should use either the original SRTM1 data or the ALOS DEM tiles, that are already available and free.

  • Curious why you recommend SRTM1 over the latest version 4? – Jon May 2 '18 at 18:14
  • SRTM1 is 30m and the latest release. USGS (EarthExplorer) version that I use looks completely void free too, as far as i've seen. I still prefer ALOS over any version of SRTM and ASTER, greater resolution due to original 5m data (subsampled to 30) and up to 5 m vertical accuracy. – Sotiris Valkaniotis May 2 '18 at 18:22
  • Ah, OK. You are recommending version 4. The "1" at the end of SRTM1 must mean something besides version. I prefer SRTM based on testing among all three--I found ALOS to have weird outliers. SRTM does too, but they were less frequent for my spot-checks. – Jon May 2 '18 at 18:24

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