[Gpsbabel-code] garmin_gpi format

[Ladislav L. <la...@ka...>]

Hello,

I've been recently reseraching possiblities of creating .gpi files for my garmin 
62s receiver with gpsbabel. The main purpose is to have an offline geocaching 
database for my current location, so that I can play even when not prepared for 
a hunt. 

I've run into some problems and want to fix them, but I'm making no real 
progress, since there are no resources on the gpi file (I don't expect full 
manual, but perhaps notes would be great) and testing stuff is really slow 
(loading a file to gps, unplugging form usb, turning on, looking around, 
connecting again...).

I wonder if you could point me into some direction on how to proceed. But before 
I ask questions, I will state what are my goals:

0) Get some geocaching extensions working (I can do this on my own, no help 
needed, but recommendations welcomed).
1) Get images working. The current state is, that I have image, but it's badly 
garbled. I don't know if the problem is in incompatible bmp (I've tried some 
variants, specifically indexed and non-indexed, various color depth) or the 
bitmap format used in gpi (I have noticed that the hardcoded image is larger 
than the image produced from bmp).
2) Get more images working. I want to have image for each geocache type...
3) Improve the code a little, maybe add some more comments and write down some 
notes on the format.

As you can see, the only big goal is the goal number 1). I can do the 0) on my 
own pretty well, since that is only the manual labour (and the only reason why I 
haven't done that already, is that it's usefull only with 1) ready). The goal 2) 
can be simulated by multiple gpi files -- not nice, but possible.

To the point on images -- they appear quiet large (larger than images I've got 
from my friend's gpi from garmin's poiloader) and garbled. I would think that 
the gps is reading the image in 24 bits per color or something like that. I 
don't really know...

Some specific questions I have are:
1) Are there any notes on this format, perhaps from someone who wrote the code?  
Was this code inspired by some other software?
2) Who wrote or maintains this code? Maybe we could talk about it and share some 
information.
3) Is there any good way to do testing and/or debugging? Some online reader?  
Good windows app?

Any insight/information is appreciated!


-- 
S pozdravem Ladislav Láska                          <la...@ka...>
Katedra Aplikované Matematiky, MFF UK               tel.: +420 739 464 167