Home
Reading
Searching
Subscribe
Sponsors
Statistics
Posting
Contact
Spam
Lists
Links
About
Hosting
Filtering
Features Download
Marketing
Archives
FAQ
Blog
 
Gmane
From: David Winslow <dwinslow <at> opengeo.org>
Subject: Re: How to determine MinScaleDenominator and MaxScaleDenominator to use in SLD
Newsgroups: gmane.comp.gis.geoserver.user
Date: Wednesday 14th October 2009 18:56:30 UTC (over 7 years ago)
One easy way is to open up the map preview for the layer of interest and 
zoom in to whatever level.  Then typing "javascript:void 
alert(map.getScale())" into your browser's address bar (replace the 
address entirely) will tell you the scale denominator for the current 
view.  If you use it as a maxScaleDenominator then your style will apply 
when you are further zoomed in; if you use it as a minScaleDenominator 
then your style will apply when you are further zoomed out.

If you need this information frequently you can make a bookmark with 
that JavaScript as the URL.

Hope this helps.

--
David Winslow
OpenGeo - http://opengeo.org/

On 10/14/2009 02:41 PM, Vitor Isaia wrote:
> Hi Andreas!
>
> Based in your explanations, what would be the values to use in the SLD 
> rules?
>
> I mean... for example, what to put here?
>
> 0
> ??
>
> then
> ??
> ???
> .....
>
> How to determine these values?
>
> May be you already showed how, but I can't get it.
>
> Thanks!!
>
>
> On Mon, Oct 5, 2009 at 10:04 AM, Andreas Hocevar  > wrote:
>
>     Hi,
>
>     Styler assumes the same screen resolution as the OpenLayers map
>     preview
>     in GeoServer, which is 25.4 / 0.28 = 90.7143 dpi. The reason for
>     that is
>     the "standardized rendering pixel size" of 0.28mm x 0.28mm, as
defined
>     in the SLD spec. OpenLayers assumes a default resolution of 72 dpi.
If
>     you want your OpenLayers application to show the scales exactly as
>     defined in SLD, you need to set the following after including
>     OpenLayers.js in your application:
>
>     OpenLayers.DOTS_PER_INCH = 25.4 / 0.28;
>
>
>     Otherwise, the scale factor would be 72 / 90.7143 = 0.7937.
>
>     Regards,
>     Andreas.
>
>     Justin Deoliveira wrote:
>     > Ahh cool, sorry i did not pick up on that you were using the
styler.
>     > Yes, hovering over the scalebar works well. However I believe
>     there is
>     > also a ticket open to renable the scale directly on the map itself.
>     >
>     > As for your question about the scale factor, i am not sure. I have
>     > cc'd one of the styler developers who should be able to better
>     comment.
>     >
>     > -Justin
>     >
>     > sc wrote:
>     >> Hi Justin
>     >>
>     >> Yes you've understood correctly. I noticed that Styler showed the
>     >> scale when
>     >> zooming in and out and this solved my problem.  I just wondered if
>     >> there was
>     >> a more scientific way of working it out.
>     >>
>     >> I also noticed that when I displayed the scale in OpenLayers
>     that the
>     >> scale
>     >> was slightly different to the one shown in Styler, is there
>     some kind of
>     >> 'factor' I need to take into account?  I seem to remember seeing a
>     >> figure of
>     >> 0.90 somewhere?
>     >>
>     >> Regards
>     >> Simon
>     >>
>     >> -----Original Message-----
>     >> From: Justin Deoliveira [mailto:[email protected]
>     ] Sent: 02
>     >> October 2009 13:31
>     >> To: sc
>     >> Cc: [email protected]
>     
>     >> Subject: Re: [Geoserver-users] How to determine
>     MinScaleDenominator and
>     >> MaxScaleDenominator to use in SLD
>     >>
>     >> Hi Simon,
>     >>
>     >> I am not sure if I completely understand your problem... but you
>     >> should be able to configure openlayers to show you what scale
>     you are
>     >> at. Then when you zoom around you can take values from the
>     scale and
>     >> plug them into your SLD.
>     >>
>     >> -Justin
>     >>
>     >> sc wrote:
>     >>> Hi All
>     >>>
>     >>>
>     >>>
>     >>> I've just started using GeoServer, GeoWebCache and Openlayers
>     but I
>     >>> do not understand how to determine the MinScaleDenominator and
>     >>> MaxScaleDenominator to use in my layers SLD file.
>     >>>
>     >>>
>     >>>
>     >>> My OpenLayers map uses Google Maps as the base layer and i have a
>     >>> shapefile stored in GeoServer that houses the points I want to
>     overlay.
>     >>>
>     >>>
>     >>>
>     >>> If I use the default 'point' style supplied with GeoServer the
>     >>> points display algeol of the time as I expect, but I would like
to
>     >>> change their style at different zoom levels but I can't find a
way
>     >>> of linking the zoom in OpenLayers to the scale in GeoServer.
>     >>>
>     >>>
>     >>>
>     >>> I think that I am on the right lines but could do with a steer in
>     >>> the right direction.  I've seen an example SLD at
>     >>> http://edit.csic.es/SLD/GMapExample.sld.xml
but these scales
>     do not
>     >>> seem to work for me.
>     >>>
>     >>>
>     >>>
>     >>> Any help would be greatly appreciated.
>     >>>
>     >>>
>     >>>
>     >>> Regards
>     >>>
>     >>> Simon
>     >>>
>     >>>
>     >>>
>    
------------------------------------------------------------------------
>     >>>
>     >>>
>     >>>
>     >>
>    
----------------------------------------------------------------------------
>     >>
>     >> --
>     >>> Come build with us! The BlackBerry® Developer Conference
>     in SF, CA
>     >>> is the only developer event you need to attend this year.
>     Jumpstart
>     >>> your
>     >>> developing skills, take BlackBerry mobile applications to
>     market and
>     >>> stay ahead of the curve. Join us from November 9-12, 2009.
>     Register
>     >> now!
>     >>> http://p.sf.net/sfu/devconf
>     >>>
>     >>>
>     >>>
>    
------------------------------------------------------------------------
>     >>>
>     >>>
>     >>> _______________________________________________
>     >>> Geoserver-users mailing list
>     >>> [email protected]
>     
>     >>> https://lists.sourceforge.net/lists/listinfo/geoserver-users
>     >>
>     >
>
>
>     --
>     Andreas Hocevar
>     OpenGeo - http://opengeo.org/
>     Expert service straight from the developers.
>
>
>    
------------------------------------------------------------------------------
>     Come build with us! The BlackBerry® Developer Conference in SF,
CA
>     is the only developer event you need to attend this year.
>     Jumpstart your
>     developing skills, take BlackBerry mobile applications to market
>     and stay
>     ahead of the curve. Join us from November 9-12, 2009. Register
>     now!
>     http://p.sf.net/sfu/devconf
>     _______________________________________________
>     Geoserver-users mailing list
>     [email protected]
>     
>     https://lists.sourceforge.net/lists/listinfo/geoserver-users
>
>
>
>
------------------------------------------------------------------------------
> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay
> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
> http://p.sf.net/sfu/devconference
>
>
> _______________________________________________
> Geoserver-users mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/geoserver-users
>
 
CD: 3ms