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I made an elevation map of my study area in Macapa, Brazil. But the region has the average elevation lesser than 30 m as I can see from my map derived from SRTM 3 second arc.

According to my knowledge some parts of the region has trees taller than 30 meter and I am afraid that my elevation map shows tree canopy elevation instead of bare land elevation.

My questions are:

  1. Is any correction implemented on SRTM 3 second arc images to remove trees and non-terrain features?
  2. I found a tree height map from NASA. Can I do: SRTM 3 second arc minus elevation height map?
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    Welcome to GIS SE! On the Tour we are reminded that each question should focus on just the single question which is most important to you. Would you be able to use the edit button beneath yours to revise it to do that, please? The other can then be researched/asked separately. – PolyGeo Aug 16 '14 at 23:15
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NASA hosts a paper that can be found here which gives detailed answer to your title question. In particular page 2, paragraph 3 and page 21 starting at paragraph 2. The short answer is no, SRTM data is not necessarily bare-earth measurement and may be tree canopy. However, radar can potentially partially penetrate tree canopies, so the given height might not be accurate of the tree canopy either.

The paper makes reference to the tree height data you mention, and points out the above issue of accuracy and how that height was derived. It makes specific mention of the need for further research in methods of processing the data to improve ground or tree height accuracy because the data values can vary with vegetation type, density, etc. Note the paper is from 2007, so some of the cited sources may have produced further results since then.

Related Question: Does NASA DEM contain objects?

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I'm not an SRTM expert, not even an SRTM novice. http://www.opendem.info/technology.html provides a nice methodology for correcting for tree canopy height.

So, no, it does not appear that the SRTM data is corrected. However, there are ways to do such a thing.

Good Luck.

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