Terrain data - When is it deleted off the Pixhawk?

ArduCopter
1

From reading the guides on Terrain data, I completely understand how it decided what terrain data to request from the ground station. And I get that it stores it on the Pixhawk SD card. And that the Pixhawk pulls it from the SD card into memory as needed in flight. But I don’t see documented anywhere is what happens after? Does that terrain data stay on the SD card forever? Stay until space is running low? Stay until the next terrain data request regardless of space? How much terrain data can it store on the SD card?

The reason I ask… I really like the ability to use terrain data. BUT, we don’t always have the luxury of Mission Planner and the internet out in the field. I could cheat to load the terrain data at home first. Say by making a survey mission covering a huge area of my neighborhood. That would force the AP to request all that terrain data from MP, which would be uploaded to the SD card. But how long will that data last? When is it deleted if ever? etc etc.

2

Revisiting this question…

3

Anyone? Anyone? Beuler?

4

That’s a worthwhile question, and I too would like to know.

Can anyone answer this or point us to the Wiki page that covers this?

5

@tridge or @peterbarker might know the answer to this one - good question, and something that would be useful to document in the wiki

6

@tridge or @peterbarker might know the answer to this one - good question,
and something that would be useful to document in the wiki

I do not believe it ever is.

“delete” and “unlink” do not exist in the terrain directory.

7

I’m guessing the flip side of that is that space consumed by terrain data is unavailable for logs?

8

I’m guessing the flip side of that is that space consumed by terrain data is
unavailable for logs?

Yes, but unless you’re doing something out-of-the-ordinary, the size is
trivial.

If you were using a 32GB card you could have the database for the entire
planet and still have room for logs.

9

Cool. Good to know. Thanks Peter!

10

Well in that case, I think @Michael_Oborne should add a “world domination terrain data” button in Mission Planner :slight_smile:

So once the terrain data is sent from the GCS to the Pixhawk, it goes to the SD card and stays there indefinitely? Unless you remove the SD card and manually delete it, it doesn’t go away?