Re: [Geoserver-users] Problems with TextSymbolizer label near tile edges

[Arne K. <ar...@ti...>]

  Very sorry, I remembered incorrectly about 3x3. You are right that 4x4 
metatiling is used by default in the layers configured for GeoServer.

So
- the metatiling factors
- the fact that for every zoom level the tiles are doubled in size, and
- the fact that the Brits decided that the Prime Meridian runs straight 
through London
are all conspiring against you, London will always be at the edge of a 
metatile.

I'm still not sure why the gutter doesn't take. Did you define the layer 
with a new name in geowebcache.xml, to distinguish it from the old one?

-Arne


On 7/14/10 2:55 PM, Andy Norman wrote:
>    Ok, I am now trying to take a very methodical approach to this now.
> I've created a test dataset:
>
> insert TwnTest (town, geom) values ('L0',
> geometry::STGeomFromText('POINT (0 0)', 4326))
> insert TwnTest (town, geom) values ('LR',
> geometry::STGeomFromText('POINT (-0.12565612792968881 10)', 4326))
> insert TwnTest (town, geom) values ('L1',
> geometry::STGeomFromText('POINT (-1 20)', 4326))
> insert TwnTest (town, geom) values ('L2',
> geometry::STGeomFromText('POINT (-2 30)', 4326))
> insert TwnTest (town, geom) values ('L3',
> geometry::STGeomFromText('POINT (-3 40)', 4326))
> insert TwnTest (town, geom) values ('L4',
> geometry::STGeomFromText('POINT (-4 50)', 4326))
> insert TwnTest (town, geom) values ('L5',
> geometry::STGeomFromText('POINT (-5 60)', 4326))
> insert TwnTest (town, geom) values ('L6',
> geometry::STGeomFromText('POINT (-6 70)', 4326))
> insert TwnTest (town, geom) values ('L7',
> geometry::STGeomFromText('POINT (-7 80)', 4326))
>
> At zoom level 1 it looks like this, all the labels display:
>
>     http://www.norman.cx/photos/links/zoom1.png
>
> At zoom level 2 it looks like this, again all labels showing, several
> straddling the tile edge:
>
>     http://www.norman.cx/photos/links/zoom1.png
>
> At zoom level 3 it starts to go wrong, every label within 4 degrees of
> the tile edge is not drawn:
>
>     http://www.norman.cx/photos/links/zoom1.png
>
> Is what you can see here just normal tile edge issues or is something
> else going wrong ? From the descriptions of meta tiling I've seen here,
> I expect it to deal with and draw these labels correctly.
>
> I also notice that the label at 0,0 is drawn up to level 3 and then
> never drawn in any zoom levels beyond that. I also note that 4x4 meta
> tiles appear to be the default and that there are 4x4 tiles at level 3.
>
> I suspect therefore that meta tiles aren't sliding, but are in fact a
> fixed grid. That would mean that beyond level 3 a point at lat/long 0,0
> will always be on the edge of a meta tile and the label will therefore
> never be drawn. Does that make sense ?
>
> I guess I next have to work out why my metatiling and gutter settings
> for GWC aren't using used. I've set the meta tile to 5x5 and set the
> gutter to 128, but it doesn't appear to actually be being used (as 16
> tiles get cached at a time, suggesting a 4x4 meta tile is being used).
>