<div>Tilecache doesn't really know any details about different projections. If you tell it to render -360 to -50 in epsg:4326, it will try give that a shot. Different rendering engines might treat this request differently. I'd suggest trying these requests tilecache is making to your wms (mapnik?) and seeing how it responds.</div>
<div><br></div><div>Note that with certain seed parameters, tilecache will try to pad the extent you requested, even if that padding goes outside of the definition of what the projection technically covers....</div><div><br clear="all">
-Josh<br>
<br><br><div class="gmail_quote">2010/1/17 Bjørn Sandvik <span dir="ltr"><<a href="mailto:bjorn@thematicmapping.org">bjorn@thematicmapping.org</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi,<br>
<br>
These are the tile bounds calculated by TileCache when pre-generating<br>
map tiles for zoom level 0 and 1 (world map, spherical mercator):<br>
<br>
C:\Python25\python.exe tilecache_seed.py country_labels2 0 2 -f<br>
<br>
###### (0, 0, 0), (1, 1, 0)<br>
<br>
Cache miss: -20037508.34,-20037508.34,20037508.3384,20037508.3384,<br>
Tile: x: 0, y : 0, z: 0, time: 0.177000045776<br>
00 (000000, 000000) = (-20037508.3400 -20037508.3400 20037508.3384<br>
20037508.3384) [0.1810s : 5.461/s] 1/1<br>
<br>
Cache miss: 20037508.3384,-20037508.34,60112525.0168,20037508.3384,<br>
Tile: x: 1, y: 0, z: 0, time: 0.0149998664856<br>
00 (000001, 000000) = (20037508.3384 -20037508.3400 60112525.0168<br>
20037508.3384) [0.0160s : 9.896/s] 2/1<br>
<br>
Cache miss: -20037508.34,20037508.3384,20037508.3384,60112525.0168,<br>
Tile: x: 0, y: 1, z: 0, time: 0.0150001049042<br>
00 (000000, 000001) = (-20037508.3400 20037508.3384 20037508.3384<br>
60112525.0168) [0.0170s : 13.447/s] 3/1<br>
<br>
Cache miss: 20037508.3384,20037508.3384,60112525.0168,60112525.0168,<br>
Tile: x: 1, y: 1, z: 0, time: 0.0130000114441<br>
00 (000001, 000001) = (20037508.3384 20037508.3384 60112525.0168<br>
60112525.0168) [0.0150s : 16.591/s] 4/1<br>
<br>
###### (0, 0, 1), (2, 2, 1)<br>
<br>
Cache miss: -20037508.34,-20037508.34,-0.000799998641014,-0.000799998641014,<br>
Tile: x: 0, y: 0, z: 1, time: 0.0699999332428<br>
01 (000000, 000000) = (-20037508.3400 -20037508.3400 -0.0008 -0.0008)<br>
[0.0710s : 15.918/s] 1/4<br>
<br>
Cache miss: -0.000799998641014,-20037508.34,20037508.3384,-0.000799998641014,<br>
Tile: x: 1, y: 0, z: 1, time: 0.0680000782013<br>
01 (000001, 000000) = (-0.0008 -20037508.3400 20037508.3384 -0.0008)<br>
[0.0700s : 15.580/s] 2/4<br>
<br>
Cache miss: 20037508.3384,-20037508.34,40075016.6776,-0.000799998641014,<br>
Tile: x: 2, y: 0, z: 1, time: 0.00799989700317<br>
01 (000002, 000000) = (20037508.3384 -20037508.3400 40075016.6776<br>
-0.0008) [0.0090s : 17.717/s] 3/4<br>
<br>
Cache miss: -20037508.34,-0.000799998641014,-0.000799998641014,20037508.3384,<br>
Tile: x: 0, y: 1, z: 1, time: 0.0639998912811<br>
01 (000000, 000001) = (-20037508.3400 -0.0008 -0.0008 20037508.3384)<br>
[0.0660s : 17.275/s] 4/4<br>
<br>
Cache miss: -0.000799998641014,-0.000799998641014,20037508.3384,20037508.3384,<br>
Tile: x: 1, y: 1, z: 1, time: 0.0739998817444<br>
01 (000001, 000001) = (-0.0008 -0.0008 20037508.3384 20037508.3384)<br>
[0.0750s : 16.664/s] 5/4<br>
<br>
Cache miss: 20037508.3384,-0.000799998641014,40075016.6776,20037508.3384,<br>
Tile: x: 2, y: 1, z: 1, time: 0.00800013542175<br>
01 (000002, 000001) = (20037508.3384 -0.0008 40075016.6776<br>
20037508.3384) [0.0100s : 18.113/s] 6/4<br>
<br>
Cache miss: -20037508.34,20037508.3384,-0.000799998641014,40075016.6776,<br>
Tile: x: 0, y: 2, z: 1, time: 0.00899982452393<br>
01 (000000, 000002) = (-20037508.3400 20037508.3384 -0.0008<br>
40075016.6776) [0.0100s : 19.500/s] 7/4<br>
<br>
Cache miss: -0.000799998641014,20037508.3384,20037508.3384,40075016.6776,<br>
Tile:x: 1, y: 2, z: 1, time: 0.00799989700317<br>
01 (000001, 000002) = (-0.0008 20037508.3384 20037508.3384<br>
40075016.6776) [0.0100s : 20.794/s] 8/4<br>
<br>
Cache miss: 20037508.3384,20037508.3384,40075016.6776,40075016.6776,<br>
Tile: x: 2, y: 2, z: 1, time: 0.00999999046326<br>
01 (000002, 000002) = (20037508.3384 20037508.3384 40075016.6776<br>
40075016.6776) [0.0110s : 22.030/s] 9/4<br>
<br>
----------------------------------------<br>
<br>
Why are several of these tiles out of bounds defined by spherical<br>
mercator (-20037508.34, -20037508.34, 20037508.34, 20037508.34). I've<br>
made a Google Spreadsheet showing the mismatch:<br>
<a href="http://spreadsheets.google.com/pub?key=tBo1PLS1uldW01SgSv3se8A&single=true&gid=0&output=html" target="_blank">http://spreadsheets.google.com/pub?key=tBo1PLS1uldW01SgSv3se8A&single=true&gid=0&output=html</a><br>
<br>
[country_labels2]<br>
type=Mapnik<br>
mapfile=C:\EarthAtlas\maps\merc_country_labels2.xml<br>
spherical_mercator=true<br>
<div class="im"><br>
Cheers,<br>
Bjørn<br>
<br>
<a href="http://blog.thematicmapping.org" target="_blank">http://blog.thematicmapping.org</a><br>
<br>
<br>
<br>
</div>2010/1/16 Bjørn Sandvik <<a href="mailto:bjorn@thematicmapping.org">bjorn@thematicmapping.org</a>>:<br>
<div><div></div><div class="h5">> Cross-posting from Mapnik-users:<br>
> <a href="https://lists.berlios.de/pipermail/mapnik-users/2010-January/002824.html" target="_blank">https://lists.berlios.de/pipermail/mapnik-users/2010-January/002824.html</a><br>
><br>
> I'm experiencing a strange error with TileCache rendering labels with<br>
> Mapnik and a point shapefile. For zoom level 1 only labels on the<br>
> southern hemisphere (the two bottom tiles) are rendered - see the<br>
> image attachment on the link above. The other zoom levels are rendered<br>
> correctly. It works when using standard latitude/longitide projection<br>
> (EPSG:4326), but not "spherical mercator".<br>
><br>
> Is this an issue with TileCache?<br>
><br>
> Cheers,<br>
> Bjørn<br>
><br>
> <a href="http://blog.thematicmapping.org" target="_blank">http://blog.thematicmapping.org</a><br>
><br>
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