Elevation question

[tsm00]

Hi Quinten,

I am processing some S2 imagery over Lake Erie, which is 174m from sea level.

I have a question on how to use the parameter settings for this. There is an 'elevation' field in the parameter settings, default = none. I couldn't explicitly find this in the manual, but if I wanted to manually enter a fixed elevation, do I set this as: 'elevation=174' for this lake?

Also, does this over-ride using DEM files? I tried using the DEM=True, but it acolite couldn't find my files, even though I had downloaded them.

I have a tried a few things, but couldn't get the DEM files to be found.

Finally - do I need them if the 'elevation' field is specified.

Thanks!

Tim


Here is the output:

Processing 1 scene...
Processing scene 1 of 1...
2019-10-29 10:06:46 - Processing /Volumes/data3/S2/Erie/DSF//S2A_MSI_2019_07_04_16_19_11_MERGED_L1.nc
DEM files not found in /Users/tim/Desktop/acolite_py_mac/data/SRTMGL3.003
Please download http://e4ftl01.cr.usgs.gov/MEASURES/SRT ... L3.hgt.zip to /Users/tim/Desktop/acolite_py_mac/data/SRTMGL3.003/N41W084.SRTMGL3.hgt.zip
Please download http://e4ftl01.cr.usgs.gov/MEASURES/SRT ... L3.hgt.zip to /Users/tim/Desktop/acolite_py_mac/data/SRTMGL3.003/N42W084.SRTMGL3.hgt.zip
Please download http://e4ftl01.cr.usgs.gov/MEASURES/SRT ... L3.hgt.zip to /Users/tim/Desktop/acolite_py_mac/data/SRTMGL3.003/N41W083.SRTMGL3.hgt.zip
Please download http://e4ftl01.cr.usgs.gov/MEASURES/SRT ... L3.hgt.zip to /Users/tim/Desktop/acolite_py_mac/data/SRTMGL3.003/N42W083.SRTMGL3.hgt.zip
Traceback (most recent call last):
File "/Users/quinten/gitdist/acolite/launch_acolite.py", line 30, in <module>
File "/Users/quinten/gitdist/acolite/launch_acolite.py", line 25, in launch_acolite
File "/Users/quinten/gitdist/acolite/acolite/acolite/acolite_cli.py", line 85, in acolite_cli
File "/Users/quinten/gitdist/acolite/acolite/acolite/acolite_run.py", line 216, in acolite_run
File "/Users/quinten/gitdist/acolite/acolite/acolite/acolite_ac.py", line 477, in acolite_ac
File "/Users/quinten/miniconda3/envs/acolite_dist_new/lib/python3.6/site-packages/numpy/lib/nanfunctions.py", line 1205, in nanpercentile
TypeError: ufunc 'true_divide' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''
[82000] Failed to execute script launch_acolite

exit 0
+ exit 0

[quinten]

Hi Tim

The elevation is used to derive pressure to interpolate between LUTs. If you specify an elevation (in metres) it will override the other options (ancillary data/DEM). Setting elevation=174 would indeed work, but if you want to use the DEM you can leave elevation=None.

Are you using the binary distribution or the source code? If you are using the binary distribution, it may be worth a try extracting the DEM zip files. I only added the zip file support after the 2019-03-26 release.

Hope this helps!

Quinten

[tsm00]

Hi Quinten,

Thanks for the explanation. I'll stick with setting the elevation for now.

I am using the binary distribution of Acolite on a mac, and I have indeed unzipped the DEM files (both zipped and unzipped are in the correct directory) but I get the same error.

I haven't tried recompiling, but maybe I'll give it a shot.

If you have any other thoughts on the DEM files for Mac, I'd be happy to try other variations.

Thanks!
Tim