Dave, it looks to me like you're seeing effects of collision avoidance
in label cacheing. I would expect those artifacts to be more extreme
near the edges of the images.
I wonder what would happen if you greatly increased your edge buffer.
If you need a 4096x4096 tile, then produce a 12288x12288 (3x3) image
and carve out the central 1/9. That would reduce the artifacts but
can't be guaranteed to eliminate them. I think the only guarantee
would be to explicitly specify label locations, and turn off the label
collision avoidance.
I've copied this thread over to the new list, as the lists.umn.edu
address's demise is imminent.
Hal
On Feb 29, 2008, at 3:52 AM, Dave Weaver wrote:
MapServer doesn't seem to be entirely consistent with placement of
symbols.
Consider these 2 overlapping images:
http://www.screenshots.cc/view_image/5437e415/thayer-east.png
http://www.screenshots.cc/view_image/b0aae448/thayer-west.png
This is causing me problems. I need to generate lots of map tiles
covering
a large area. These tiles need to be able to be displayed next to
each other
seamlessly. To avoid partial symbols on the edge of tiles, I'm
rendering
tiles too large then trimming off a 256-pixel border around each.
However,
when symbols are plotted in different places on adjacent tiles, I'm
getting
partial symbols around the edge of my trimmed tiles which *don't*
have a
corresponding partial symbol on the adjacent tile. (if you see what
I mean).
I'm using MapServer 5.0.0 from the ms4w package.
What can I do to cure my problem?
Thanks,
Dave.
