[mapserver-users] Maximum number of points in a poligon

[Rahkonen Jukka]

Hi,
 
The biggest lake has more than 5000 islands and lots of bays and everything so I was thinking that a simple automatic tool would for sure break the topology, and sooner than I could have explained how a good tool should behave I had splitted the ten biggest lakes by hand. I can't even imagine how hard it would to be to code such a tool. It should not make invalid geometries and it should create new vertices so that new polygons could zigzag between the islands without splitting those, and the new pieces should have about same total number of vertices with variable number of islands. It was rather easy to iterate with bare eyes. 
 
-Jukka-



________________________________

	Lähettäjä: sebastianovide at gmail.com [mailto:sebastianovide at gmail.com] Puolesta Sebastian E. Ovide
	Lähetetty: 27. lokakuuta 2010 16:21
	Vastaanottaja: Rahkonen Jukka
	Kopio: mapserver-users at lists.osgeo.org
	Aihe: Re: [mapserver-users] Maximum number of points in a poligon
	
	
	Do you spliited the polygons manually or you have some script ? perhaps using gdal ?
	
	
	On Wed, Oct 27, 2010 at 1:36 PM, Rahkonen Jukka <Jukka.Rahkonen at mmmtike.fi> wrote:
	

		Hi,
		 
		All I can say is that with our data the service went all to slow for the end users long before jamming.  We have been splitting the biggest lake polygons into pieces with no more than 45000 vertises because that was the limit of reasonable speed in our environment.  But in that case the limiting factor was the database and "contains" queries, not Mapserver.  Anyhow, splitting the lakes was good for Mapserver too.  For some other layers we have made simplified versions for the far-away zooms. Simplifying is better for WMS use if polygons are drawn with different outline colour but it gives a bit more work with building the scale dependent layers.
		 
		-Jukka Rahkonen-

________________________________

			Lähettäjä: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] Puolesta Sebastian E. Ovide
			Lähetetty: 27. lokakuuta 2010 14:57
			Vastaanottaja: mapserver-users at lists.osgeo.org
			Aihe: [mapserver-users] Maximum number of points in a poligon
			
			
			Hi All, 

			I have a shape with 2M polygons. The biggest one has 13k points. It works very well, and fast enough.

			I have another shape with 300k polygons and the biggest one has 800k points... This shape hangs MapServer !... and I have to kill the process by hand using kill -9. (see the other thread: process survive after killing apache). The shape files can be opened with ogrinfo though

			Is there a maximum number of points for single polygon supported by MapServer ?

			Thanks
			-- 
			Sebastian E. Ovide
			
			
			




	-- 
	Sebastian E. Ovide
	
	
	

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