Currently I have some photographs captured by DJI, and in their EXIF I saw that it contains: GPS Altitude, Absolute Altitude, Relative Altitude, GPS Latitude, GPS Longitude.
These images will be used for creating TIFF file by Pix4D. After creating TIFF file from those images, I use the GPS Lat/Long of one of those images and then extract the elevation from TIFF file and that elevation is different with the altitude from the image. I also use Google Elevation API and it also different from the altitude of the image (and the elevation from my raster, too).
For example, with this lat/lon (GPS value from EXIF) 15.99849675/108.246482777778 I get those 3 values:
- Altitude (GPS and Absolute) in the EXIF: 62.9m Above Sea Level
- Relative Altitude: 49.80
- Elevation I get from TIFF: 21.9400272369
- Elevation I get from Google API: 4.45
So my questions are:
- What is the meaning of the altitude in EXIF of an image?
- The accuracy between the elevation extract from TIFF and the Google elevation API