On Wed, Mar 2, 2011 at 4:17 PM, Steve Way
<[email protected]> wrote:
> Hi All,
>
>
>
> I am currently testing  GS-RC1 – we will be updating to RC2 soon in
> preparation for the final release.
>

Ok, then this is new to me. Do you have sample data and styles to reproduce it?
If so attach them to a bug report on jira.codehaus.org and then let's
wait for a developer
to have enough spare time to look at it.
If you cannot share the data we'll have to wait for someone that can,
or for a developer
to stumble into the same issue.

>
> Has anyone else noticed the strange behaviour of the MapScaleDenominator?
>
>
>
> For instance, In my client (ArcView 10) my Scale is set to 1:8000, but when
> looking through the geoserver logs noticed:
>
>
>
> creating rules for scale denominator - 7,559.539
>
>
>
> Which is causing havoc with my SLDs.

I normally don't play with proprietary software but the scale denominator is
a common WMS issue for clients mixing different data sources (or just not
computing the scale the way OGC tells us to).
The WMS/SLD spec imposes an extremely simplified formula to compute the
scale denominator over lat/lon data, one that (hang tight) basically assumes
the earth is a cylinder. From the spec:

"For geographic coordinate systems, which use angular
units, the angular coverage of a map should be converted to linear
units for computation
of scale by using the circumference of the Earth at the equator and by
assuming perfectly
square linear units"

Even if you are playing with projected data there is still the dpi
that might give the scale
a different value, the SLD spec mandates roughly 90 dpi:
"The “standardized rendering pixel size” is defined to be 0.28mm ×
0.28mm (millimeters)."

However your software could be using something different. For example
with the OpenLayers
previews in GS we have to force it at that value to have consistent
(and standard compliant)
scale computation, as by default it would use 75.

Long story short, you can't generally assume the scale will be
computed the same way
by all softwares involved in your deploy.

Hope this helps

Cheers
Andrea

-- 
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead

Via Poggio alle Viti 1187
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