3

I'm trying to open data downloaded from NASA's Earthdata site in ArcGIS 10.4.1. Specifically I'm trying to open "GLAS/ICESat L2 Global Land Surface Altimetry Data (HDF5) V034" (Image below, highlighted in blue, can be found by searching 'Iran Glas').

enter image description here

I have the data downloaded, there are multiple .H5 files which I've tried adding to an open ArcGIS .MXD by using the 'Add Data' tool. Once the files are open in the 'Add Data' wizard, there are even more files to chose from, most of these I'm not interested in. It is difficult/near impossible for me to figure out which files are actually important for importing.

I'd like to know if there is an easy way to filter the data so I can extract only elevation data and then, produce a DEM from the extracted data. I've tried opening several files that prompt to produce pyramids for them - this gives me some hope that the data I want is in specific files. However, it is taking an extremely long time for them to open and build on my machine (too long considering how many files there are to open).

I've started looking at converting the .H5 files to .LAS files, mainly prompted by following ESRI's advice (here: http://www.esri.com/esri-news/arcuser/summer-2013/5-ways-to-use-lidar-more-efficiently).

Would this significantly reduce processing time?

I have a reasonable idea of what I want but need advice on the process and whether this is feasible.

3

First, please note that GLAS is waveform and not discrete return data. All lidar is not the same! Second, before it was decommissioned, the sensor was rapidly decaying and required extensive calibration of the data. This is not done by NASA and is a very complex process.

I do not see where ESRI is recommending GLAS and I am fairly certain that you will not be able to use the data in the way that you are thinking.

  • Thanks for the feedback. I'm pretty new to using remote sensing data so I was unaware of these pitfalls. Apologies, ESRI wasn't recommending GLAS I was following their advice on dealing with lidar data as a whole (which, like you say, is not all the same). I have SRTMGL1- 30m and ALOS AW3D30 DEM data which I am I'm processing using the Hydrology Tools from ArcGIS. I was hoping to build or find another data set that could possibly add more detail to my work, hence trying to get hold of the GLAS data (which I assumed would have elevation data to create a DEM with more detail). Thanks again! – S. Jackson May 2 '18 at 12:09
  • There are additional complications in using lidar for hydrologic modeling. One has to be very mindful about scale and the effect that it has on geomorphological derivatives. Routeing algorithms can also be very sensitive to surface noise in the data, potentially producing erroneous flow directions and trapped accumulation. Bigger is not always better. – Jeffrey Evans May 2 '18 at 16:37
  • Again, thanks for the feedback - I really appreciate it. I'll stick with my SRTM and ALOS AW3D data. Cheers, Simon. – S. Jackson May 3 '18 at 16:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.