thanks, Thanks for your answer. now I have a clear idea of the problem
Regards.
----- Original Message -----
From: "Randy George" <rkgeorge@anonymised.com>
To: <geoserver-users@lists.sourceforge.net>
Cc: "'Omar Zevallos'" <omzeta@anonymised.com>
Sent: Friday, February 24, 2006 11:45 AM
Subject: [Geoserver-users] Viewer with Geoserver
Hi,
Adobe SVG ASV3.03 has problems rendering large datasets. The nice
thing, though, about OWS is that it provides a straightforward seamless
interface to very large data sets (such as your 30000+ polygons). You will
need to limit the number of polygons in small scale views. Here a couple
things you could try:
1. At small scales show points (circles) rather than polygons. I assume the
polygons are house symbols. Even using points your 30000+ points could
overload the client rendering. This would mean adding another
table/datastore calculating a centroid for each existing polygon.
2. Do not allow polygons or points to render until zoomed in to a reasonable
level. Unfortunately GeoServer doesn't let you set scale hints yet:
<ScaleHint min="31.426248379135124" max="33670.98040621619" />
So you will have to provide scale visibility on your own server
side. I am hoping that future versions of geoserver will implement the scale
hints. The problem is what to show at small scales.
3. Combine a WMS image/jpeg with WMS image/svg+xml. In other words use the
more or less static WMS jpeg, png etc until zoomed to a certain level and
then switch to image/svg+xml with the necessary event listeners to make it
useful on the client. Note: with very large datastores the time to render
server side is also prohibitive at small scales. (another reason scalehints
would be helpful)
Since you are using Adobe ASV here is a sample svg interface you might be
interested in seeing:
http://www.web-demographics.com/OWSGeothermal
There are about 6000 Geothermal SMUWells at the Western US zoom level shown
as point symbols. There are about 50000 Quatenary Faults,
gml:MultiLineString elements, which will not render at the US level of zoom
without blowing up the ASV rendering on a 512Mb client.
This experimental site uses client side svg for both WMS and WFS. For WMS
the image is embedded as an svg image element with an xlink:href pointing to
the WMS like this:
<image id="img" x="-125.0" y="-53.0" width="60.0" height="30.0"
xlink:href="http://onearth.jpl.nasa.gov/wms.cgi?styles=&service=WMS&ServiceN
ame=WMS&request=GetMap&layers=BMNG&format=image/jpeg&srs=EPSG:4326&bbox=-125
,23,-65,53&width=1000&height=500">
</image>
This allows local Geoserver WFS site layers to overlay selected WMS.
The handy thing about svg (or any declarative xml graphic spec) are
all of the things you can do with event listeners on the client, which is
why the svg export from geoserver WMS is fairly useless(static), as you
pointed out.
I found using the WFS export and then decorating with custom event
capability to be a more flexible approach. You could do the same with the
svg. In both cases you need server side control in addition to geoserver to
add client capability. I still wonder about injecting event listener
attribution through sld somehow, since listeners could be considered just a
form of rendering like fill or stroke.
rkgeorge
-----Original Message-----
From: geoserver-users-admin@lists.sourceforge.net
[mailto:geoserver-users-admin@lists.sourceforge.net] On Behalf Of Omar
Zevallos
Sent: Thursday, February 23, 2006 10:41 PM
Cc: geoserver-users@lists.sourceforge.net
Subject: [Geoserver-users] Viewer with Geoserver
Hi there, months ago, I have been looking for a viewer (for Browser) to show
cadastral data through geoserver. I have tried MapBuilder and Adobe SVG
Viewer.
With MapBuilder I did not continue working because I did not find the way to
work with events (onclick, mouseover, etc), and I´m working with SVG now,
but I have troubles with overload data, since, I have a layer that includes
lotes (polygons that draw a house in the map) of all my region (about 30000
rows). I do not know like handling so many data in the browser...
I suppose that one of you has had the same problems, I wish a suggestion
about this...
Thanks in advance
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