[mapserver-users] polygon border artifacts

[thomas bonfort]

with a recentish version of mapserver, try setting
PROCESSING "APPROXIMATION_SCALE=FULL"
on your ocean layer, to avoid feature simplification (it will slow
down the rendering if the resolution of your data is much greater than
the resolution of the requested map).

--
thomas

On Fri, May 4, 2012 at 12:16 PM, Sven Geggus
<lists at fuchsschwanzdomain.de> wrote:
> Hello,
>
> the brilliant osm coastline tool from Jochen Topf
> (http://blog.jochentopf.com/2012-04-19-more-coastlines-stuff.html)
> enables for creating nice ocean or landcover polygons from
> Openstreetmap data.  Well, this is where my mapserver problem
> starts...
>
> For illustration of the problem I just created ocean polygons around
> canary islands
>
> http://home.geggus.net/pub/ocean-canary-islands.zip
>
> They are in sperical mercator using a huge overlap of 30meters to
> avoid artifacts.
> However artifacts (which seem to depend on scale) still arise:
>
> http://home.geggus.net/pub/ocean.png
>
> Here is the mapfile and shp2img command I used for rendering:
>
> shp2img -o ocean.png -m ocean.map -e -1917656.09 3248262.91 -1839384.59 3326534.41 -s 512 512
>
> MAP
>
>  OUTPUTFORMAT
>      NAME agg
>      DRIVER AGG/PNG8
>      FORMATOPTION "INTERLACE=OFF"
>      MIMETYPE "image/png"
>  END
>
>  EXTENT         -180 -85 180 85
>
>  IMAGECOLOR 255 0 0
>
>  WEB
>      METADATA
>        "ows_enable_request" "*"
>         wms_srs "EPSG:4326 EPSG:3857"
>      END
>  END
>
>  PROJECTION
>  "init=epsg:3857"
>  END
>
>  LAYER
>     PROCESSING     "CLOSE_CONNECTION=DEFER"
>     NAME           "ocean"
>     TYPE           POLYGON
>     STATUS         ON
>     DATA           "ocean-canary-islands"
>     PROJECTION
>        "init=epsg:3857"
>     END
>     CLASS
>       STYLE
>         COLOR 128 255 255
>       END
>     END # of class
>  END # of layer
> END
>
> The only workaround I found so far is to use an outline:
>
> OUTLINECOLOR 128 255 255
> WIDTH 1
>
> Is this a bug in mapserver or is there something else which I can do?
>
> Sven
>
> --
> "Ich fürchte mich nicht vor der Rückkehr der Faschisten in der Maske der
> Faschisten, sondern vor der Rückkehr der Faschisten in der Maske der
> Demokraten" (Theodor W. Adorno)
> /me is giggls at ircnet, http://sven.gegg.us/ on the Web
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