When do we need Apply-Orbit file

[dtnguyen]

How and when we need Apply-Orbit file?

[ABraun]

Auto UTM zone in the graph file?

How and when we need Apply-Orbit file?

the earlier the better I’d say. A suggestion:

Radiometric & Geometric Correction Workflow

for SLC data I would suggest Thermal noise removal Calibration to Beta0 TOPSAR Deburst Apply Orbit file (Speckle filtering) Radiometric terrain flattening Range Doppler Terrain Correction If you don't need the phase information you can also download it as a GRD product and only apply the following: Thermal noise removal Apply Orbit file Calibration to Beta0 (Speckle filtering) Radiometric terrain flattening Range Doppler Terrain Correction or (if you don't have much topography): The…

[bext_la]

Hi

l got error while prossesing Apply Orbit File (AOF)

how to AOF effect our result? if l don’t use, what will my data loss?

[ABraun]

seems like SNAP cannot access the internet sorce for the orbit files. Can you please check if SNAP is allowed to pass your firewall?
More notes on this here:

S-1 Thermal Noise Removal

maybe your firewall blocks it. Please make sure that port 443 is open in your firewall settings. How to Open a Port on Windows Firewall Windows and Mac: How to open ports in your firewall

[bext_la]

Thank you for reply. So is it important Orbit file?

[ABraun]

depends on what you want to do with your data.

[bext_la]

So what is orbit file function? where may l get information about this? on Machine learning and change detection need orbit file or?

[ABraun]

Orbit files improve the positional accuracy of the product. If you want to perform interferometry and want to coregister two SLC products at sub-pixel accuracy, application of orbit files helps to make it more precise.

If you simply want to work with backscatter intensity, applying range doppler terrain correction with SRTM 1 ArcSec should also be sufficient. Still, it is strange that your machine cannot access the orbit sources.

Please also check the Help section of the module: