[ gpsdrive ] automatic nasa blue marble maps

[Hamish]

Hi,

I now have the NASA Blue Marble functionality working. Updated
instructions can be found in the Documentation/README.nasamaps file.
The code for it still works, for the most part.

the instructions boil down to:
- download .tif file(s)
- convert to .raw (see instructions)
- move .raw file to ~/.gpsdrive/nasamaps/
- start gpsdrive


bug: the create_nasa() fn calls create_nasa_mapfile() every second, and
while the actual tile is not remade (takes 2-3 seconds) unless you move
off screen, the popup percent done window is constantly flashing by.


wish: allow direct read from a PPM/PNM file directly, or better yet from
the source .tif (or PNG or JPG) file. those are about 650mb total for
both east and west images, while the .raw files are 2.8gb for both.

.raw are just .ppm/.pnm with the top three (header) lines of the file
removed. I briefly looked at allowing .ppm format by finding the file
offset after the 3rd newline in the file (skipping #comment lines) and
adding that to the SEEK_SET offset in the read() step. This failed as
ftell() wanted *FILE but the files are opened with a FID int. I then
tried to read() in the first 1024 bytes of the file into mybuffer[] and
scan for the 3rd \n, but started to lose interest at that point. 


wish: if the nasa maps are present add a tickbox for them in the
Map Control window under "Included mapsets" so you can turn them off.



Hamish