[Mapnik-users] understanding mapnik/tilecache projection
crschmidt at metacarta.com
Fri Oct 24 22:45:58 CEST 2008
On Fri, Oct 24, 2008 at 02:37:34PM -0600, Jamie Robertson wrote:
> - When i try this, the tiles (via tilecache.py) are rendered, but the
> output is just the bg color, and none of the data is rendered. Do i need to
> furthur specify the projection in the *tilecache.cfg* file? such as:
you don't need to specify the projection again, but you *do* need to
specify the resolution and extents of your data. (extents are a 4-tuple
seperated by commas, resolution is typically 'maxresolution=' with a
single value: often the equivilant of taking the maximum width of the
data and dividing by 512.)
To use with OpenLayers, you'll further need to ensure that these
settings match between OpenLayers and TileCache.
> projection= +proj=lcc +lat_1=45 +lat_2=49 +lat_0=44.25 +lon_0=-109.5
> +x_0=600000.0000000001 +y_0=0 +ellps=GRS80 +datum=NAD83
> +to_meter=0.3048006096012192 +no_defs
> - I've also tried this procedure with shapefile data that is already in
> the UTM12N projection *EPSG: 32612* without success.
> Any ideas?
> -Jamie Robertson
> Mapnik-users mailing list
> Mapnik-users at lists.berlios.de
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