[OSM-dev] Garmin maps

[Andreas Brauchli]

> What I envisage is something perhaps similar to osmarender, but instead
> of OSM->SVG just does OSM->Simplified OSM. Style sheets could be used to
> define and customise what gets outputted. A separate stage may be need
> to simplify the number of segments in large ways, etc.
> 
> The img generator would then just take an OSM file for each level of
> zoom and combine them into a single Garmin map.
good idea, but probably not that fast and very memory consumpting,
depending on the xml processing style used

> The alternative is to do it inside the img generator, but that would
> seem to require reinventing the wheel.
maybe not, i've seen a good technique of doing this on the list:
rounding to grid
take a point(x,y)
x'=round(x/precision)*precision;
same for y

do that for all points and remove all x' and y' which already exist
(respectively don't create those if they exist)

you can do that for any precision wanted. but make sure to remove
footways/minor whatever at higher levels because otherwise the data
(ways) is still there, just abstracted and what we do want is remove
information at higher levels.

or just take this method to create the OSM->simplified-OSM xslt

andreas