Altum GSD issues

[Christina K]

Not a 100% sure if this is a bug but according to Micasense, the Altum camera has a ground resolution of:

"5.2 cm per pixel (per EO band) at 120 m (~400 ft) AGL and 81cm per pixel (thermal) at 120m"

When processing Altum imagery the actual resolution that is automatically calculated does not seem to match and is way to low/coarse.

In the report of Agisoft we can see that the altitude is around 80 m and the ground resolution used for the OrthoMosaic is approx 10.5 cm which is way to coarse according to the MicaSense datasheet. The resolution used for export was automatically defined by Agisoft.

We are processing the data following this guide: https://agisoft.freshdesk.com/support/solutions/articles/31000148381-micasense-altum-processing-workflow-including-reflectance-calibration-in-agisoft-metashape-professi

Is this a bug or are we doing something wrong? Any ideas why the ground resolution could be lower?

Thanks in advance!

[Christina K]

We continue to process more Altum data and everytime the GSD is coarser than we would expect.

[toxicmag]

Hi Christina,

we have a correct correlation between flight altitude and GSD which corresponds also to the mission planning in advance.
Nevertheless we experience trouble in getting correct GSD values when batch processing the data.



Greetings

Alex

[Alexey Pasumansky]

Hello Christina,

I was not able to reproduce the issue on the sample Altum datasets that we have. Can you please provide example of the project, where the issue is observed in PSZ format (containing only alignment results in order to reduce the file size) to support@agisoft.com? Original images are not needed.