[OpenLayers-Users] Hover control sample (share)

Roald de Wit roald.dewit at lisasoft.com
Mon Jan 19 19:52:52 EST 2009


Hi Alexandre and Andreas,

A while ago I created a proof of concept where I simplify the features
with FeatureServer (FS) [1] depending on the resolution.
Chris Schmidt was so kind to point out that the tolerance for
simplifying is directly related to the map resolution.

What I do is add an extra parameter to my WFS request (to FS):
tolerance=0.010986328125 for example. That value is the actual
resolution.
(In my FS configuration I have enabled the 'Simplify' WPS module)

This works quite well for geometries with many vertices. It does not
reduce the number of features though!
Note that Simplify in FS does not support multigeometries atm.

Regards,

Roald

[1] http://featureserver.org/

On Fri, 2009-01-16 at 08:05 +1030, Andreas Hocevar wrote:
> Hi Alexandre,
>
> On Thu, Jan 15, 2009 at 7:52 PM, Alexandre Dube <adube at mapgears.com> wrote:
> > Yeah, I saw your example a couple of days ago.  It's a great tool.  As
> > vector features are longer to draw than samples images generated by WMS
> > requests I find this quite useful.
> >
> > The slow rendering of vector features has been one of my worries.  A
> > common practice is to normalize the geometry for a given scale or have
> > different data per scale on the server side.  With that in mind, I
> > wanted my vector layer to load features from different data source.  See
> > the example :
> >
> > http://dev4.mapgears.com/bdga/options-by-zoom-hover-bdga.html
> >
> > This combine the above idea ( multiple data sources ) with the Hover
> > control.  The result is quite fast.  What do you think ?
>
> This is a good idea! But it seems there is a lot of work to do on the
> server side to prepare all the different detail levels for a WFS. Are
> you using WPS for that?
>
> Andreas.
>
--
Roald de Wit
Software Engineer
roald.dewit at lisasoft.com

Commercial Support for Open Source GIS Software
http://lisasoft.com/LISAsoft/SupportedProducts/


The contents of this email are confidential and may be subject to legal or professional privilege and copyright. No representation is made that this email is free of viruses or other defects. If you have received this communication in error, you may not copy or distribute any part of it or otherwise disclose its contents to anyone. Please advise the sender of your incorrect receipt of this correspondence.



More information about the Users mailing list