[Tilecache] Huge dateline gap

[Christopher Schmidt]

On Tue, Nov 18, 2008 at 04:07:19PM -0800, Roger André wrote:
> It's been pointed out that I didn't include a great deal of information
> about my setup.  I doubt it will matter much, but here goes:
> 
> I am using TileCache to read a large (14400x7200) raster with global
> extents.  The raster projection is in lat/lon WGS84.  TileCache is set to
> read this data via a MapServerLayer layer type, with settings that match the
> example in the out-of-the-box tilecache.cfg (metaTile=true, metaSize=5,5,
> metaBuffer=10).

set metaBuffer:0,10 and you may see your edge defects disappear to some
extent.

Probably something like this is the problem:

11:55 < FrankW> The problem is that GDAL transforms the destination area
back to the source coordinate system by sampling a grid of points over
the region.
11:55 < FrankW> But points right on the international date line might
transform two different ways.
11:55 < FrankW> so the region selector is missing the last swath of
data.


In GDAL-land, you can use:

11:42 < FrankW> klokan:  Try adding "-wo SOURCE_EXTRA=120" to your
gdalwarp commandline without the quotes


But I don't know how to use that through MapServer.

> I am using the following package versions in my stack, and they have all
> been built from source:
> 
> gdal-1.5.2
> mapserver-5.2.0
> proj-4.6.1
> proj-datumgrid-1.4
> tilecache-2.04
> --
> 
> 
> 
> On Tue, Nov 18, 2008 at 3:17 PM, Roger André <randre at gmail.com> wrote:
> 
> > Ok, so now that I've gotten meta-tiling with edge buffering to work, I seem
> > to be able to better control the missing pixel rows that were causing
> > horizontal stripes in my Google Map tiles.  Only now I have a huge gap at
> > the international date line.  I also have a band of missing data at the
> > extreme South edge of my tiles when I am past Zoom Level 5.  I can probably
> > live with that, but since my data set is global, I find it interesting that
> > it's getting cut off, and only on the South side.
> >
> > Anyone seen this before?
> > --
> >

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-- 
Christopher Schmidt
MetaCarta