[UPDATED] Force SRTM *.dat on the SD card "not working"


I would like to upload an entire country SRTM data to my SD card, It will only weight about 40-50 MB total, but every time I am doing a flight plan with all the country, with terrain, It will only load about 11 *.dat on the SD, missing a lot of spot, and I have a 8 GB SD card.

How can I force it?



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Ok, so I just did a lot of tests using the plane SITL.

First I did some flight plans with parallel lines every 2km on a 110 x 110 km square, the same surface than a single SRTM *.TIFF or *.HGT files, the goal was to get a *.DAT files ready to use on the SITL terrain folder. with a terrain spacing parameter of 30m I got files around 25MB, which is very close to the actual size of the SRTM download from Earthexplorer.

Then, I did a simple flight, 150km from takeoff and after 2 minutes airborne, I disconnected mission planner “GCS Failsafe off” and waited or connected Qgroundcontrol, without elevation data and internet.

In both case, after a couple of KM, the plane stopped receiving terrain data, meaning terrain-pending at maximum and terrain-loaded at 0, even if I have 24 000 square km of terrain data on the SD. So arduplane would use the last elevation as a reference point, if the terrain is raising, the plane would crash.

So it seems that Arduplane is never really reading what is on the SD card and how can I be sure terrain following RTL will even work at long distance?

If a dev could have a look I would be grateful.


Hey Guys

Any update on this ?

I am running the latest SITL, loaded a long flight plan, checked that all the terrain file are loaded inside the SITL terrain folder, then took off

After disconnecting MP, 5 min after take off and reconnecting it 20 min after the simulated plane was 70m bellow the terrain altitude selected, but a couple of seconds after reconnection, the plane went back to it’s target terrain height

So what is the point of having terrain data on the SD if you always need mission planner connected to your drone? It’s not working


Just got the terrain following without the GCS communication working.

You need to go on this website here ,download the area where you plan to fly, install it on your SD and you are good to go :wink:

Or simply use QGroundcontrol …

Please explain how to

Use daily build release, it will download in QGC then automatically upload to your board
Thanks to @DonLakeFlyer

Well it does not work, at least on the plane SITL, it’s telling me terrain transfer done, but nothing new on the simulated SD, I can’t transfer any mission without error messages, and I have regular QGC crashes.

At the moment, manually copy files to a SD card and fly, feels a lot more simple