mis-joined tiles.

[Richard Greenwood]

On 6/19/07, Dave Weaver <dave.weaver at zen.co.uk> wrote:
> I'm experiencing a problem with horizontal lines on some of my maps, like this:
>
> http://img363.imageshack.us/my.php?image=whitelinewm2.jpg
>
> The lines only appear at some zoom levels, and at some tile sizes. For
> example this request:
>
> http://localhost:8080/cgi-bin/mapserv?map=map/Media_Base_Brown.map&layers=lod5&styles=&service=WMS&width=256&format=image/jpeg&request=GetMap&height=256&srs=EPSG:54004&amp;version=1.1.1&bbox=-20037508.34,0.0,0.0,20037508.34

We can't see your localhost. Maybe post a screen shot or an accessible url.

> Can anyone give me a clue as to how I can fix this?

I always build tiles with  a few pixels of overlap between tiles. I
got in this habit due to problems with other software (not MapServer)
so I'm not sure that it is important with MapServer.

A reprojection may require rotation of the image, which create
"wedgies" - narrow triangles of no-data areas along the image borders.
Ideally the adjoining tiles fill the no-data wedgies, but you would
need to set transparency so that no-data areas do not mask out
underlying tiles.

-- 
Richard Greenwood
richard.greenwood at gmail.com
www.greenwoodmap.com