[Talk-ca] OSM GPS maps...

[simon at mungewell.org]

Hi Sam,
Did you mention that you had a 'standard scheme' for naming/numbering maps
which conforms to the Alberta Topographic numbers?

The reason I am asking is that I tried out my map at the weekend and found
it very slow to render with all the contours.

I have worked out how to get graduated contours (so more detail only
happens when you zoom in), but am also investigating whether it makes
sense to split the map further into smaller pieces - if this will make it
render quicker on smaller devices.

Looking at:
http://www.maptown.com/canadiantopographical/albertantsindex.html

The top maps have:
Sheet number (ie. 83) which contains a alpha-tile (16 tiles, A through P)
and each of those contains number-tile (1 through 16).

Assuming we don't want huge downloads does it make sense to make a map of
sheet/alpha-tile available as a zip, and then further split that into
number-tile within the gmapsupp.img ?


This could give something like:
xx080100.zip - zip file containing...
xx830100.img - overview map for 83-A,
gmapsupp.img - actual download, which contains...
xx830101.img through xx830116.img - the individual tiles for 83-A-01
through 83-A-16 (also available as seperate files incase someone wants to
compile their own gmapsupp.img).

Or do you already have a better scheme?
Simon.

PS. I am rendering 25m, 50m and 100m contours at the moment.