[ gpsdrive ] GPSDrive with Mapnik and OSM: claims "No map available for this position"

[Hamish]

> If usefull;  maybe we can change the standard projection of
> GpsDrive

please please please stick with lat/long WGS84 (epsg code 4326) Plate Carée for lat/lon mode, as it is what all GPSs report; and something standard and known (ie with an *official* EPSG code) for projected mode.

k.i.s.s., even if others are going with their own custom thing.

I suppose it is "Google's Mercator" based on a sphere ellipsiod (ie not WGS84!) which OSM may be using? (??)

it is guess by proj4 in /usr/share/proj/esri.extra as:
#
#  Chris' funny epsgish code for the google mercator
#
<900913> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs <>

see also "+nadgrids=@null +no_defs"
http://trac.osgeo.org/proj/wiki/FAQ#ChangingEllipsoidWhycantIconvertfromWGS84toVirtualEarthMercator


Also consider that mercator is a pretty outmoded projection to use as it is so distorting at high latitudes.


Please give me a few days to consult the experts before changing anything anyway.. it would be helpful to know definitively what OSM is using- is it Google's Merc?


cheers,
Hamish