I received this message from someone on the Spark Pilot forum. Maybe an avenue to explore. @Adam_Carp?
Vilco said, " I just created an application in C# which would automate the process of cycling thtough every image in a folder (asking the user wich folder) and search the image in a kind of a log file (asking the user for its path) then read the full coords and correct the exif fields of the pic via exiftool. Unluckyly IwI still haven’t found such a logfile among the many log / dat / txt files I found in the DJI Go app folders and in the drone itself via DJI Assistant. There are som elogs, someone I had to upload to Airmap to decrypt, which lista ticks, which must be a time measurement unit, and perfect coordinates for all of the flight time, but I can’t find a way to understand at which line has the picture been taken. Some files even go to af far as 10 or 12 decimal places, probably obtained by some calculations on the 6 decimal places numbers coming from the GPS.
If someone knows how to link a Spark picture to one of these fully geotagged log files, I’d be more than glad to offer my app to whoever wants to play with these exif geotag data."