Re: Projection map ratio problem

Yes! I reran the test with LLXY projection and the ratios
stay the same. And I agree with the WMS client difficulty,
which we've been having also.

Allan Doyle wrote:
>
> Something to keep in mind is that the projections use the center of the screen as the
> center latitude and center longitude. In other words, you're not sliding a fixed
> projection around under a window, you're recomputing the projection for each pan/zoom.
> That could be what you're seeing.
>
> It's precisely this behavior that makes it hard to use openmap as a WMS client or
> server. The xxxview projections were an initial attempt at changing this.
>
> Allan
>
> rs@syncline.com wrote:
>
> > Mercator, by default for MapBean. Are you saying that the
> > ratio of pixel and geographic rectangles should be
> > different in Mercator, or are you saying that the
> > variability in the ratios will change across the earth?
> >
> > Don Dietrick wrote:
> > >
> > > Hi Raj,
> > >
> > > What projection were you using to run these tests? I would expect them
> > > to be different for different projections, and for different latitudes
> > > within the same projection. This is affected by the degree/pixel ratio
> > > characteristic of a projection, which is likely variable in most cases,
> > > depending on latitude. Equal Arc projections (constant degree/pixel
> > > ratios) should be OK, though, like the LLXY projection and the CADRG
> > > projection within the same zone.
> > >
> > > - Don
> > >
> > > rs@syncline.com wrote:
> > > >
> > > > I've been doing some tests, and it seems that the ratio
> > > > of the MapBean's screen width and height (r) is different than
> > > > the ratio of the MapBean's geographic width and height (geor).
> > > > See the results of a few extents below. Can anyone explain
> > > > what may be happening here?
> > > >
> > > > minx -130.5 -84.2403 -85.2855
> > > > maxx 131.0625 -75.2403 -74.1951
> > > > miny -78.062 29.31935 28.64211
> > > > maxy 78.06198 36.77261 37.37486
> > > > w 465 465 573
> > > > h 460 460 539
> > > > gr 1.675351 1.207526 1.26997
> > > > r 1.01087 1.01087 1.06308
> > > >
> > > > thanks,
> > > > Raj
> > > >
> > > > --
> > > > Raj Singh, Syncline
> > > > rs@syncline.com
> > > > +1(617)986-1000
> > > > MapCiti.com...it's your town on the web
> > > >
> > > > --
> > > > [To unsubscribe to this list send an email to "majdart@bbn.com"
> > > > with the following text in the BODY of the message "unsubscribe openmap-users"]
> >
> > --
> > Raj Singh, Syncline
> > rs@syncline.com
> > +1(617)986-1000
> > MapCiti.com...it's your town on the web
> >
> > --
> > [To unsubscribe to this list send an email to "majdart@bbn.com"
> > with the following text in the BODY of the message "unsubscribe openmap-users"]
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Allan Doyle adoyle@intl-interfaces.com
> International Interfaces +1 781 433 2695 (Office)
> http://www.intl-interfaces.com +1 781 254 9484 (Mobile/Voicemail)

-- 
Raj Singh, Syncline
rs@syncline.com
+1(617)986-1000
MapCiti.com...it's your town on the web
--
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