Clipping the DAT file at country rather than continent level for Terrain following

I have been using arducopter terrain-following feature by downloading the terrain data from
But it is getting repeated every time if I have to go to a new area. The maximum radius we can generate using the above link is 400km. So will have to download manually all the files. Or I can also download data on a continental level. But this increases the requirement for onboard storage. Is there a way that I can define the boundary at the country level, clip the data and download it in DAT format so that I can store it on the autopilot’s SD card?

I don’t know the file format but…
I tried to document.getElementById("radius").max = 3000 to increase the radius but seems like the server has a limit in this line:

You can clone the repository and run it by removing that line with the radius that suits your application :slightly_smiling_face:

Thank you for the reply.
Do you have any idea why is there a limit on this?

I wouldn’t be supporised if it was done for performance reasons.