[Xastir] Interesting APRSdos map!

[Henk de Groot]

Hello,

Wayne Carvalho from Hawaii send me a map the other day for conversion to a 
pocket APRS map. It turned out to be an APRSdos map, which I have not dealt 
with before.

Finally yesterday I started looking at the APRSdos map format, just 
basically trying to figure out the corner points. My math kept showing 
strange results so I looked at the Xastir code how it decodes these maps. 
It turns out the map covers a very big area, but more strangely it goes 
from 90:00:00.00E to 306:02:41.28E. Normally E/W values do never get bigger 
than 180 degrees, 181:00:00.00E would be written as 179:00:00.00W. On 
Xastir the map shows up, but half of it sticks outside the earth's grid on 
the right hand side... I can't change the 306:02:41.28E value to a west 
value since then the right border would be more left than the left border 
(hmm,how does one say this, does it still make sense?).

Anyway, PocketAPRS has hard borders at 180W and 180E which cannot be 
crossed, so a map smack in the middle over his area will not work. But if 
APRSdos is able the show this map correcly, I assume Xastir should too, so 
it should have a notion that the earth is round (at least a cylinder 
approximation for this one...).

I'm very interested in your reaction and if someone can make it show up 
correctly in Xastir...

For people who want to try, I stored the map at:
http://www.homepages.hetnet.nl/~pe1dnn/pac_west.zip

Kind regards,

Henk.

P.S. Of course after this is fixed the next challenge is a polar map of the 
North Pole or the Antartic area... I wonder if APRSdos can do that too...