[mapserver-users] Re: polygon border artifacts

[Rahkonen Jukka]

Hi,

Perhaps PNG8 does not have enough many colours for showing the artifacts?

-Jukka Rahkonen-

Lime, Steve wrote:
 
> I'm unable to recreate the artifact with a simple test case 
> though so I'm not exactly sure what's going wrong. This mapfile
> defines a couple of overlapping polygons and there is no 
> rendering issue.
> 
> MAP
>   SIZE 512 512
> 
>   IMAGETYPE PNG8
> 
>   EXTENT 0 0 1000 1000
>   IMAGECOLOR 255 0 0
> 
>   LAYER
>      NAME "test"
>      TYPE POLYGON
>      STATUS DEFAULT
>      FEATURE
>        POINTS 100 100 600 100 600 600 100 600 100 100 END
>      END
>      FEATURE
>        POINTS 300 70 800 70 800 800 300 800 300 70 END
>      END
>      CLASS
>         STYLE
>          COLOR 128 255 255
>          # OUTLINECOLOR 0 0 0
>        END
>      END # of class
>   END # of layer
> END
> 
> Online at: 
> http://maps1.dnr.state.mn.us/cgi-bin/mapserv60?map=/usr/local/
mapserver/apps/test/ocean/test4.map&mode=map
> Your original test case (+labels): 
> http://maps1.dnr.state.mn.us/cgi-bin/mapserv60?map=/usr/local/
mapserver/apps/test/ocean/test.map&mode=map
> 
> Steve
> 
> -----Original Message-----
> From: mapserver-users-bounces at lists.osgeo.org 
> [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of 
> Sven Geggus
> Sent: Wednesday, May 09, 2012 8:18 AM
> To: mapserver-users at lists.osgeo.org
> Subject: [mapserver-users] Re: polygon border artifacts
> 
> "Lime, Steve D (DNR)" <Steve.Lime at state.mn.us> wrote:
> 
> > Do outlines fix things at all zoom levels?
> 
> Not really. The Workaround which is working best for now is 
> using a very big polygon Overlap of 100Meters (Talking about 
> Google Mercator here) which I feel is way to much and an 
> outline with of 1. To completely get rid of artifacts I would 
> need an Outline width of 2, but this is not small enough IMO.
> 
> > What about the possibility of fixing the data?
> 
> The bug is clearly with mapserver here, the data is fine IMO. 
> The tool used for generation of the tiles does already allow 
> for generation of arbitrary overlap widths 
> (https://github.com/joto/osmcoastline/).
> 
> > I mean, unioning the ocean polys into one, or better yet 
> deriving land 
> > polygons from that data.
> 
> No, unfortunately both of them are not an Option!
> 
> 1. Unioning the polygons:
> I presented a small shapefile just to demonstrate the problem.
> The original file I want to use contains ocean tiles covering 
> the whole world. So this has been spitted into tiles for a reason!
> 
> 2. Land polygons:
> These are also not an option because I want to use the ocean 
> tiles to cover inaccurate hillshading derived from srtm. This 
> will not work the other way round.
> 
> The only thing I could imagine as a solution on the data side 
> would be the clipping of the hillshades by means of the polygon shape.
> 
> Regards
> 
> Sven
> 
> --
> TCP/IP: telecommunication protocol for imbibing pilsners
> 	                             (Man-page uubp(1C) on 
> Debian/GNU Linux)
> 
> /me is giggls at ircnet, http://sven.gegg.us/ on the Web 
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