Who is Dani?Getting Negative Altitude data on Phantom4 Pro & Mavic Platinum when mapping. Anyone no if Dani has issued a fix?
Getting Negative Altitude data on Phantom4 Pro & Mavic Platinum when mapping. Anyone no if Dani has issued a fix?
Or is the OP looking at the altitude data shown in Exif info for the captured images?
Altitude data shown in EXifOr is the OP looking at the altitude data shown in Exif info for the captured images?
This gets asked about frequently.Altitude data shown in EXif
It's not related to GPS, GCPs, software or the altitude shown in the app.Some softwares use the ellipsoid of the GPS takeoff point though so it depends on what you are using. ???
It's not related to GPS, GCPs, software or the altitude shown in the app.
That's the raw Exif info applied to the images by the camera.
Phantom4 Pro & Mavic Platinum when mapping.
Sorry to disagree, but it is.
GPS. Different makes of drones can report exif data differently. IE Yuneec vs DJI and if the data is not recorded in the correct altitude parameter, or if they write a new altitude parameter then some softwares will not read it at all.
View attachment 116448
GCPs. Working along with the GPS, if it is not reporting correctly then GCPs will fix it. From the OP's reference to mapping.
Software, see above and the fact that if GCP's are not used then they can report +/-.
Mapping
On DJI aircraft the altitude fields in the EXIF data have been mislabeled for years, and only recently corrected in some firmware. The DJI GPS altitude data field is actually barometric AMSL based on a standard atmosphere - hence the obvious discrepancies.
Incorrect EXIF GPS and Elevation
Mavic 2 Pro flight and pictures excellent, but image EXIF data shows altitude was a bit over 115 million meters...which would be impressive if true. Lat/Lon also consistently off by about 3/4 mile. This matters when feeding pics into Pix4D photogrammetry software. Anyone else check their EXIF...mavicpilots.com
Firmware v01.00.0510 EXIF altitude changes
A number of people have noted that the latest firmware has changed the EXIF altitude data, but DJI did not specify exactly what had changed. I guessed that it was what I had been bugging them about – namely that the altitude data fields were mis-labeled, e.g. : GPS Altitude Ref ...mavicpilots.com
Correct, but the values written to the exif are not derived from the barometer and vision algorithm. That is just what is used to position the aircraft over the ground including terrain following. This tells you that it is using both (maybe in just terrain following?). One to know the elevation of the drone in comparison to the SRTM that was loaded and the other to increase the accuracy of the drone's distance from the terrain.
So it's happening only at the see or near to it? Otherwise it wouldn't be logical because the takeoff point is measured by the same method as during the flight and as I understand only different air pressure can make that difference.