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DEM errors

Last summer I mapped a large area, 2X3km. the flights were completed between the months of July and September. I used several different launch points for the project. When I processed the complete project I got some strange DEM errors, which in retrospect is not surprising.
I have since broken the projects into zones that were flown on the same day from the same launch point. I have processed each of these zones as separate maps, but I still get weird results. The attached image is an example. The area that appears dark blue is not the lowest area in this map as is evident from the brook that flows through it. The area to the southwest should appear lower that this area.
Almost every map from this project has similar errors in the DEM.

I am using a DJI Mini3 with map Pilot Pro.
I have not included ground reference images in my processing as I was concerned that these may be causing the errors I was seeing. I am only interested in relative elevation as I plan to use surveyed ground reference points to level the various maps to the same datum.

Any suggestions as to what may be causing this error and how I can fix it would be much appreciated.

Goowiddy

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I can't find an account for your name or email address so we can't look it up. 

In general, you should only process images that are taken from a single takeoff location into a single map. If you mix takeoff locations and are providing ground reference images the last one encountered in the dataset will be used. Also, if you are caring about the accuracy of the elevation numbers in your results you really need to be using 80% overlap for you data collection. You can get away with less if you are just looking for a nice ortho image but elevation accuracy really needs at least 80% overlap. 

Zane
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Sorry, I logged in with google, not my Maps Made Easy account.

This comment is from my Maps Made Easy account.

Heather Loader 0 votes
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This Image is the difference between the government DEM and the MapsMade Easy DEM.

The range is about 40m and appears to be radial in nature with the centre being about 40m lower relative to the edges.

Heather Loader 0 votes
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Here is your overlap report that shows you are using about 65% overlap in your data collection. As noted previously, if you care about your elevation data you need to be using 80+%. The error in the DEM is showing warping that is common with low overlap. 

Zane 0 votes
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