Terrain awareness altitude differs between missions

It sounds like you maybe started a new account that was not where you had the mission data saved previously. Otherwise, you could have just synced it all in by hitting the 'Sync' button.

The terrain awareness is calculated at the time of flight. Depending on what your subscription level is it could be using a different terrain data source. They should be close though... 

You can't generally do photogrammetry with images that are collected at different times because the differences in the lighting will make it so the features don't match. Not sure what you are mean with the metadata, please provide examples. 

I don't see an account for you in our system so I can't see what is going on in there. Let us know what your username is so we can look up the account.  

Thanks for the quick response!  The account has username "straaljager".  Unfortunately, the terrain is 200 acres of very dense, untracked bush, so getting it all done in a single go - or even a single day - just isn't possible :(  

Here's a side-on view of a scatterplot of the data opened in WebODM.  The tan line is a river bed flowing left to right, which first seems to run uphill in the new data, then downhill as expected in the old.  The new data is several metres above the old too.  I checked the "details > altitude" field of some of the individual images within a mission, and even adjacent images have 5-10m difference in altitude (and also shows as around 60m, the height above the ground was 80m.  I can understand there being an offset (perhaps relative to launch altitude?) but I expected it to be a bit more consistent than that?  Or is the drone really flying up/down 5+ metres between shots??)
I think that our biggest worry is that even though there are differences between each of our missions in the trial software, we could still match them up OK ... but getting the new paid one to play nicely with that old trial data just isn't happening!  I'm sure we're doing something dumb, but I just can't figure out what ..! Any advice is very much appreciated :)

You need to refer to the relative altitude numbers in the XMP tags to see what was really going on between images. Every time you restart the aircraft is going to get a new GPS fix that can provide VERY different elevation fixes. It can be hundreds of meters off... 

That is why Map Pilot Pro records the image at takeoff. That way Maps Made Easy can detect that image and use it as a starting point and use the relative altitude numbers from there to provide super accurate and consistent elevation numbers from a given takeoff location. You can read more about that here:

https://support.dronesmadeeasy.com/hc/en-us/articles/206208583-Ground-Reference-Images

The bad news is, you probably aren't doing that correction in your processing so you have to deal with the different GPS derived elevation data. 

You really can't mix data for the same location from different visits though but since you aren't using us for processing we can't help much there. 

I don't know what flights you are specifically talking about but the last 5 in your account were all at about 80 meters AGL. 

Looking at the KML for the flight I can see that there are some height differences between the adjacent passes due to slight error in the virtual stick controls but that shouldn't be affecting the outputs because it is reflected in the tags. But the other sources are more likely going to be the issue in your reconstruction. That, and the mixing visits with different lighting.  

Thanks for the thoughts, but it still doesn't explain how we were able to get reasonably good results from the free trial (yes, even with different lighting on different days with wildly different take-off points).  I think there were about 10 different missions to make up most of that data.  The only thing that's tripping us up now is the paid version!  Ah well, I'll chalk it up to general weirdness and struggle on. 

The differences may have been due to terrain or wind conditions too. There isn't any difference in the paid subscription vs the free Pro Trial.