Giles Evans
 lvl.1
United States
Offline
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Manitol Posted at 2019-1-26 17:42
Thank you for your reply. I guess I was hoping for a little more technical depth about that file's purpose. I did delete if off the SD card before I read your reply. It deleted without any issue and did not appear to affect video recording when I did a brief test flight afterward. I suspect that the drone's firmware will just create a new file to log data to if it cannot find an existing one. Pardon me for saying so, but I would not think that file is a system file for two reasons 1) it was stored on the external SD card, which would be a poor design choice for a critical system file, since there is no guarantee that an SD card will even be installed in the drone, or that a user won't replace an existing SD card with a new one with more capacity. 2) The file extension of ".gis" is a very specific choice with a specific meaning (Geographical Information Systems) recognized by a wider community outside DJI. A hex dump reveals that the header is "GIS". This file has all of the hallmarks of a data file, not a system file. If I had to guess, it would be that it is indeed a GIS file, but of some proprietary DJI format.I would surmise that it is storing flight tracks or some other form of location data; but I was hoping someone would know - cheers.
My guess would be the .GIS file stores Almanac data downloaded directly from the satellites. Almanac data is course orbital parameters for all GPSS satellites and aids only in achieving a faster "fix" on the receiver's position. With this data, the receiver can predict an approximation of each satellites position giving you a faster, more accurate initial location to begin to fix your location upon. |
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