Hello everybody;
After upgrading to the latest Firmwares (Drone / RC) and Dji Go App, I noticed when taking pictures on the Gnd or in the Air (Manual or Auto by any App like Dji Go or Map Pilot etc...) that the Altitude values in the Exif are absolutely different than the reality (e.g: Flying at 50m will write 815 in the Exif in spite that all the used Apps are showing 50m on the Telemetry / Screen.
So; Anybody knows why this is happening and how to fix such issue ?
Thanks;
Zahi
After contacting DJI we have found that the 1.5.30 firmware populates the EXIF tags with the above sea level altitude number that is based on the GPS signal rather than the above ground level number that was used previously. GPS is notoriously bad at resolving altitude and can be off by 10s of meters... We will be addressing this within the Maps Made Easy processing using the existing Ground Reference image system.
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We haven't seen this yet. It is possible that they are recording the actual above-sea-level altitude now instead of above-ground-level. This would be awesome news.
What is the elevation of your takeoff point?
As per my DGPS (High Accuracy), the Real Time measured Altitude value of the Starting Point (Take off) is 804 m ASL, however; the taken picture on the Gnd (at the Take off point) showed 763.5 in the Exif.
So what do you think Tudor ?
No clue! Even with DGPS you can be off by a lot in elevation. If you want you can try to email the one of the images to mapping@dronesmadeeasy.com and we can take a look at it.
Try checking the elevation using Google Earth or some other public database.
Has it happened on subsequent missions?
Images have been sent to you.
The actual New Altitude values (not AGL) are being written in the Exif since the last most recent updates of the Drone 1.5.30 and RC ( In All the taken pictures and by any used App either for iOS or Android)
WoW That's a significant issue for elevation mapping, do the record the Baro Altitude anywhere in the EXIF? If so, could actually be good overall.
We still have access to all the data we need to continue making accurate elevation maps.
We have added a new tool for converting the bad GPS altitude data that gets written into the GPS Altitude EXIF value to a corrected value based on a user provided elevation or ground reference image.
https://www.mapsmadeeasy.com/tag_fixer
This will allow for people not using our Maps Made Easy processing system to process their data elsewhere while taking advantage of the steps that we do behind the scenes.
