Changes between Version 2 and Version 3 of Processing/Py6S_vs_Hyperspectral
- Timestamp:
- Oct 21, 2015, 10:21:45 AM (9 years ago)
Legend:
- Unmodified
- Added
- Removed
- Modified
-
Processing/Py6S_vs_Hyperspectral
v2 v3 15 15 === Running Py6S for hyperspectral delivery check === 16 16 17 You can plot the at-sensor radiance spectra recorded by hyperspectral senso nr and compare it to the at-sensor py6s model using the script check_fenix_spectra_py6s.py. This procedure should be done during the hyperespectral delivery check.17 You can plot the at-sensor radiance spectra recorded by hyperspectral sensor and compare it to the at-sensor py6s model using the script check_fenix_spectra_py6s.py. This procedure should be done during the hyperespectral delivery check. 18 18 19 The simplest version of the script looks for a ra mdom vegetation pixel at nadir and plots its spectra recorded by the Fenix sensor versus the predefined py6s vegetation type without atmospheric correction.19 The simplest version of the script looks for a random vegetation pixel at nadir and plots its spectra recorded by the Fenix sensor versus the predefined py6s vegetation type without atmospheric correction. 20 20 21 21 Go to delivery project directory that you want to check. Example: … … 41 41 42 42 43 If you want to run the model with different set ings, click here for more advanced techniques such as:44 -Plot s epectra for only one flightline in a directory with several ones. Or a specific flightline with different names on IGM, NAV and level1b.43 If you want to run the model with different settings, click here for more advanced techniques such as: 44 -Plot spectra for only one flightline in a directory with several ones. Or a specific flightline with different names on IGM, NAV and level1b. 45 45 -Chose a pixel by its given (lat,lon). 46 46 -Chose a pixel by its position on the grid (x,y). … … 54 54 Py6S has several parameters needed to run the model. For this script, ARSF have selected the most convenient ones for our use but do not expect perfect match of the hyperspectral spectra recorded from our sensor against the Py6S. A more detailed explanation about Py6S parameters and settings used by ARSF can be found here 55 55 56 Both curves (Fenix and Py6S) should match general features. The peaks and depression (reflecfance-absorption) caused by vegetation have to match and there should be no other spikes on the Fenix spectra that does not match the Py6s. However, note that it is probably to have a spike on some Fenix spectra flightlines on the bands around band 349, close to 900-950 nm. This is caused by the shift on the SWIR bands detected on on October 2014 and those pixels are listed as bad pixels, therefore the spectra recorded by Fenix is correct. You can find a picture il ustrating this issue which also suggest the type of spike you have to look for when they are not on the overlapping region.56 Both curves (Fenix and Py6S) should match general features. The peaks and depression (reflecfance-absorption) caused by vegetation have to match and there should be no other spikes on the Fenix spectra that does not match the Py6s. However, note that it is probably to have a spike on some Fenix spectra flightlines on the bands around band 349, close to 900-950 nm. This is caused by the shift on the SWIR bands detected on on October 2014 and those pixels are listed as bad pixels, therefore the spectra recorded by Fenix is correct. You can find a picture illustrating this issue which also suggest the type of spike you have to look for when they are not on the overlapping region. 57 57 58 58 Under_picture: Figure shows Fenix vs Py6S. Both spectra matches except for a Fenix spike close to 950 nm. No other spikes or depressions like which does not match the Py6S model should be found outside that region.