Wrong file Format for QGIS? Wrong measuring in QGIS

Data Processing - Discussion and Q&A
1

Good evening,

I hope my problem will be understandable, as my english is not that good.

I tried the drone deploy 30d trial and did a test flight over an area, where I could do measuring on ground so that I have absolute data sets to compare. After the flight, I did some measuring in the drone deploy web surface, everything seems really acurate, I was absolutely satisfied. I exported the map in different epsg codes to load it into qgis. In qgis i also measured the same points of the map and every measuring seems to be wrong. It looks like I have used the wrong epsg but I tried different times with always the same results, the measurements were different to the drone deploy web surface (and the real data of the area measured on ground). I had some mail contacr with the drone deploy support, but we came to no helpful result. It seems as there is a factor that influences the result (e.g. the real length measured on ground is 3.26m, measured in the web surface it´s 3.27m but in qgis its shown as 4.91m). I followed the steps in the tutorial (https://support.dronedeploy.com/docs/how-to-view-imagery-in-qgis#), but the problem is still there. Meanwhile the trial period is run out so that i cant do another flight to compare the different systems, but I still have the exported maps from the test flight. Has anyone an Idea, how to solve my problem?

Thanks a lot

2

What was the CRS for the layer containing the image?

3

Where can I check that in QGIS? Would it be helpful to upload screenshots of the program surface to show the problem?

4

It is at the bottom-right in the information bar. Sounds like you are using an EPSG. What is the projection of your export? Does your issue continue if you export to Mercator or WGS84?

http://www.qgistutorials.com/en/docs/working_with_projections.html

@zach1 is the pro at this, wink wink…

5

It was set to “EPSG:4326” without doing anything (presetting of qgis?). Because of your hint I looked for other options and activated the field “Spontanprojektionen aktivieren (SRP)” (should be translated like “activate spontanous projections” or sth like this), so i could choose another crs. Set it to WGS 84 / Pseudo Mercator EPSG:3857 and, oh magic, the measuring is correctly. Thanks a lot!

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