RTK and Elevations in WebODM

  1. I have UAV imagery that was collected with a live RTK correction but the images show a 6 meter difference on the ground. I am thinking that WebODM process is not taking into account the RTK position of image centers as a priority. Do I just reduce the gps-accuracy setting to a smaller number? Does that do anything? How do I make sure that the RTK GPS is honored?
  2. My elevations in the DTM and DSMs are all negative numbers as if they are Delta values from the UAV. How do I output these as Mean Sea Level elevations?
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  1. Yes, try constraining --gps-accuracy to something closer to your expected mean RTK accuracy for the dataset.
  2. That sounds like maybe a DJI dataset, right? Some folks will use exiftool to batch-edit the image EXIF to add an offset to fix this.

1: Thanks I am trying that now.
2: No, not DJI. It is a Sony camera with an AirPixel geotagging tool talking to it. It is writing the proper MSL elevation to the EXIF but somehow WebODM is changing it to an offset!

Thanks for your help Saijin!

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This is interesting… Would you be able to share the dataset?

Certainly, how can I get it to you?

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If you’re comfortable sharing in public, anything that works for you.

We also have our DroneDB.app sUAS data hosting/sharing service.

OneDrive

Saijin:
See OneDrive link above. (It may take a few minutes to sync. There should be 271 images plus 2 text log files enclosed.)
These were collected with RTK observations applied! (I believe)

My raster DSM and DTM results from WebODM had the elevations shown as negative offsets.

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I’ve tried to download from that link a few times, but it fails with:
Failed - Server problem.

Looking at the logs:
plt.odsp-common.js:1 Refused to get unsafe header “SPClientServiceRequestDuration”

Load canceled due to load timeout

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Soil Pile Data

Here is the data on DroneDB guys. Thanks!

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Sajin:
I have put the data on DroneDB in the link above.
Please let me know if that does not work.
m

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A couple more fails, one after 2GB, don’t know how far the 2nd attempt went, as the file size disappears after a while and I went out for a ride on my bike.
I’m done trying, used too much data already trying to download this 6 times now!

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Gordon
Was it failing from the DroneDB link?

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Yes, twice today. I think it said Error -Network failed. However, I was able to view other web pages and download emails, so I don’t think it was an error at this end. I suppose it is possible that Chrome doesn’t like such big files.

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Chrome has been flakey in many ways lately.
My goto is Firefox when all else fails.

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I ran it successfully with gps-accuracy at .1 Everything looks relatively accurate from what I can tell.

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I prefer FF too, was only using Chrome as I had ODM Community open here. Trying the download in Firefox now, and it is certainly downloading faster than it did with Chrome, although it will take some hours due to my slow connection.

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UPDATE- also failed at something over 2GB with Firefox. Doesn’t seem to be a problem at this end, as no problems viewing other websites.

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I don’t know what to tell you Gordon. Uplanddog above had no troubles getting it.

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