So I am flying the same lot but I get this when I use the compare tool… can I fix this? I am trying to use QGIS but have hit a wall…
Thanks
Tim
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Use GCP’s or try the method in this thread. There is a second thread embedded that has additional detail and an alternative way to do it. Basically you are using Google Earth (2-3m) or your first map (1m) to make all future maps relative.
Thanks Michael, unfortunately I started that thread and have hit a dead end. I have gotten all the way up to the end, but I still don’t understand how to nudge the maps together. I don’t doubt that it works I am just missing something. Should I re upload the old maps and tell DD to center on defined points? I thought DD already did that… but this is the result about 3 to 6 ft odd in each map.
Thanks
Tim
Hi Tim.
As far as I know, there is no way to determine a map’s horizontal position after it’s been processed. The most you can do is to provide a single point it’s known height, but not it’s horizontal position.
I can’t think of why a coordinate couldn’t be input to position a map on a single point, in the same way a processed map’s height can be calibrated on a single point, other than it might draw customers away from paying to process the map using GCPs.
They do have an alignment process, but it doesn’t work. I’ve had several maps tell me I’m within 3-5 cm and it’s obviously a foot or two off. accomplishing what you are trying to do will definitely take re uploading maps. Just take your first nap load the orthomosaic into qgis, create points and export them as a CSV file formatted correctly for gcp processing. Then re-upload any successive missions using that gcp file and they will all lineup nearly perfect.
The problem with a single point is not only are the maps shifted, but they also have rotation and warping. This is due to the fact that the satellite pads are different from day today and what the Drone was tracking one day may not even be available the next day.
Makes sense.
So either DD have to allow us to calibrate a processed map using two points, to be able to slide and rotate, or the compare functionality is only any good when processing with GCPs.
Yep, and that’s the problem right now… Smaller contractors and specific use contractors can’t fund a full GCP set up. Hope they get it better soon it is a potentially huge help.
Tim
So Im going to give it another try. I will start a new project and and upload my most recent map, add the points and make the CSV file. Once that is uploaded (Second upload of the project ) I will then reload the older maps one by one. Questions: how do they know to use the CSV file and what if they cant find all the points in the older uploads due to tree cover or new GCP checked spots not in the old ones.
Thanks
Tim
Just to be clear you don’t have to rerun the first map. Not sure if that is what you meant. Just use the map to make the GCP’s and move on to the second one. It will match the first without running the first with GCP’s. It is the control map.
Who are you talking about? DroneDeploy, the client?
You’ll have to review the maps to find at least 4 common points that exist in all of them. Typically if I want to run a project this way I will set targets on the first flight that will most likely remain, even though I am not going to ground survey them. It can be something as simple as a 60D nail or wood hub that you can return to and paint an X. Anything you put above ground usually becomes a target for not just the drone… lol.
So I’m thinking this is where I am getting lost. Using my screen shot above I have uploaded about 6 maps over time into this project. All of them have had a clear view of the roof and the concrete stairs. In the screen shot above it shows April 26 is on the left and Aug 7 is on the right (maps 5 and 6 in the project). As you can see I flew on Aug 7 with some GCP markers, albeit randomly set. I did generate a csv file based on both those markers, (that were removed and unlike to return to the exact same spots) and DD points on mostly stationary targets, using the elevations from the Aug map. DD did not like my format so I need to look at that and try to upload the csv file again. Anyhow will DD now look at my CSV file and the Aug 7 orthomosaic to align future maps or is there a way for me to nudge the maps to align. I guess part of where I’m confused is if they can not align a square roof top how will the align from my CSV file? Or am I adjusting the maps after they are processed. And is it as easy as adding the CSV (properly formatted) and every map after will align?..And do I need to re-upload the April map to align with the Aug 7 map?
Thanks for your patience,
Tim
GCP’s have to manually verified and submitted and/or tagged if they are not auto-recognized. There is no post-processing automatic alignment that can be done. You’d have to start with the first map because obviously there can be things in subsequent maps that aren’t in the first.
@Jamespipe, can you please chime in on what the intent was for auto-alignment? It does not appear to be working.
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