What are the advantages/disadvantages of each of these three file types? They are all available as formats for downloading NED data from The National Map. Which should generally be downloaded for what purposes?

  • I can only comment on IMG and ArcGrid (what sort, there are 3 types that can be called ArcGrid). Both of them are good and horrible (and at the same things too) Size: horrible, both don't support compression (much), Data types: excellent, everything from 1 bit to 64bit float, use ability: both are readable by most GIS software. Is there a specific problem you are experiencing or planning to avoid? May 5, 2015 at 4:59
  • I wasn't sure if there are any known problems related to any of the three - I have been downloading from among them randomly and haven't noticed any differences in what I could or couldn't do. Just didn't understand why three separate choices existed and wasn't sure if I was missing something.
    – traggatmot
    May 5, 2015 at 5:10
  • They should be identical. Now, if the choice was JPEG, ECW or IMG then that would be a different story.. the only way to compare these three is to decide what you want to do with them; for raster calculation (like NDVI) take the IMG as cell values aren't corrupted, for putting on a map as a background go with ECW unless your software doesn't support it then take JPEG as both JPEG and ECW are lossy compression (cell values change to make them more compressible) but give you a much smaller download size. May 5, 2015 at 5:13


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.