[OpenLayers-Users] very slow map using WKT Multipolygon with a lot of Points

[Fernando Norte]

Hi Fabrizio,

I'd had the same problem once with a huge multi-polygon. The solution for
me was create a WMS server with MapServer to generate the images tiles
instead to use the OpenLayers directly. This way we can show the results
and had some integrations with OpenLayers.WMSGeatFeatureInfo by click, and
run-time configuration in MapServer to control the layers and classes.

Since the OL runs directly in the client browser the processing maybe
varying from browser and the client machine performance.
It's happen because no matter how far is the zoom/scale the OL will read
and threath all the vertices in the polygon. If you have an algorythm to
reduce this number of vertices this still will be processed in the client
and still run slow the same way to make this happen, unless you can threath
in the server like an PostGIS query.
It's a little bit of hard code, but the performance is incredible fast.

This link bellow helps to create my WMS server:
http://augusttown.blogspot.com.br/2010/01/customize-wms-getfeatureinfo-response.html

My regards,

 *Fernando Norte*

Desenvolvedor SIGWeb

tel.(31) 2533.9900

cel.(31) 9119.8814

skype: fernandoglobalgeo

Endereço: Alameda do Ingá, 88, 6º andar, Vale do Sereno

Nova Lima/MG - Brasil - CEP: 34.000-000

www.globalgeo.com.br

"O presente documento pode conter material confidencial ou seu sigilo é
protegido por lei.
Quaisquer informações nele contida são destinadas exclusivamente ao(s)
seu(s) destinatário(s)
não devendo em nenhuma hipótese ser repassado a terceiros".




2012/11/18 Fabrizio Buratta <extremoburo at gmail.com>

> Hi all,
>
> So I'm showing the boundaries of Italian regions using openlayers, I get
> the coords from a shapefile which has a lot of points, for instance some
> regions can have a multipolygon with in total : 53000 Points.
>
> This is how I've implemented it:
>
> http://pastebin.com/r47TkmL8
>
> This is really slow on firefox / IE . Only chrome works well. What's the
> best way to get it working faster and smoothly ?
>
> Of course one answer is to reduce the points but I'd like to know if it is
> normal such slowness in my case or I did something wrong coding. And would
> be nice for me to use the whole set of points.
>
> Thanks in advance for your time
>
> --
> Fab
>
> http://twitter.com/fabrizioburatta
>
> http://www.linkedin.com/in/fburatta
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/openlayers-users/attachments/20121119/d11c419a/attachment.html>