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Name label is cut between two tiles #889
I experienced a strange behaviour of Mapnik with the name tag on OpenStreetMap.
The building is on two tiles. On zoom level 16, the name is partially rendered on one tile, the other tile contains no name.
I don't think that the tagging is wrong, because the name shows up in other zoom levels.
I think this is a bug in Mapnik.
[Ldp] I think the 'L 293' shield in the righthand metatile is causing the label to be dropped in that metatile, while somehow that shield isn't considered in the lefthand metatile, even with the 128 pixel buffer area around metatiles.
It's quite possible that the shield in the buffer area for the lefthand metatile is rendered at a slightly different position, thus not causing a collision, allowing the (partial) label to render there.
These problems only occur at metatile boundaries. For OSM, this means you can encounter them every 8x8 tiles.
Short of making a test render with the buffer area in the resulting image from the actual data, it's hard to confirm this.
[Ldp] Replying to [comment:3 loccito]:
Not at the moment. Perhaps the mapnik devs can prove my hypothesis.
I'm not sure how I can avoid it from the stylesheet. In fact, I'm pretty sure I cannot exert any control over this from the stylesheet.
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I guess your problem is same with this https://help.openstreetmap.org/questions/33485/cut-labels-with-mapnik.