[MapProxy] Spherical Mercator Projection
Frank Broniewski
brfr at metrico.lu
Wed Aug 1 00:02:21 PDT 2012
Hi list,
I have trouble overlaying my own data from a Mapnik source with
OpenStreetMap tiles. I need/want to use the official EPSG 3857 instead
of 900913 for my data [1]. From here [2] I read that 3857 is just an
alias to 900913, so the data should overlay cleanly. But unfortunately I
have a shift between my data and the OSM tiles.
So how do I need to configure my grids so that they overlay nicely with
the OSM tiles? Is
35 grids:
36 world_mercator:
37 srs: 'EPSG:3857'
38 base: GLOBAL_MERCATOR
already enough?
This is keeping me busy (read: driving me mad ;-)) already for a couple
of days. I tried also
35 grids:
36 world_mercator:
37 srs: 'EPSG:3857'
38 origin: 'nw'
39 num_levels: 19
40 min_res: 156543.0339
41 bbox: [-180, -85, 180, 85]
42 bbox_srs: 'EPSG:4326'
and other variations. I also have the problem that the map center is
jumping around when zooming in. That means when you zoom in, on a city
for example, that after the zooming process the city is shifted onto
another position than the zoom position. I am uncertain if this is a
Mapproxy misconfiguration or if it is on the OpenLayers side, but I used
the same configuration options on both sides. I still wonder if the
coverages I use are a cause for this. If only the rendering times would
be faster testing wouldn't be such a pain ..
So any hints are greatly welcome :-)
Frank
[1] one reason for this is, that 900913 isn't in the proj configuration
anymore
[2] http://trac.osgeo.org/openlayers/wiki/SphericalMercator
--
Frank BRONIEWSKI
METRICO s.à r.l.
géomètres
technologies d'information géographique
rue des Romains 36
L-5433 NIEDERDONVEN
tél.: +352 26 74 94 - 28
fax.: +352 26 74 94 99
http://www.metrico.lu
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