[mapserver-users] Wanted: Projection for the reference map

Steve Lime steve.lime at dnr.state.mn.us
Wed Aug 7 15:32:29 EDT 2002


You've not missed anything, that support is not available. Nor do I see
this being add in the near term due
to the ton's of other work going on. This should be added as a feature
request to Bugzilla so that the idea
is not lost. That said, there are other possibilties:

There is nothing that says that you can't use two different MapServer
applications on the same page. In 
reality you can mimic a reference map using a second mapping
application. If you look closely at our
Recreation Compass (http://www.dnr.state.mn.us/maps/compass.html)
application you'll see we have 
done just that. I wanted a reference map that would display a filled
box sometimes, a marker symbol
when the was too small, and nothing when the box was too large (eg. you
didn't need the reference map).
Prior to 3.6.1 you couldn't do this the the reference map object. The
solution was to use a second
little application. Worked like a charm and required on a small bit of
javascript. I would imagine you could
do the same thing with a reference map in a second projection. You'd
just have to use lat/lon as a go
between coordinate system. Worth a look if this is functionality you
need ASAP.

Steve

Stephen Lime
Data & Applications Manager

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937

>>> Havard Tveite <havard.tveite at ikf.nlh.no> 08/01/02 06:25AM >>>
I can not find a possibility to describe a projection for the
Reference Map Object in the Mapserver documentation. Have I
overlooked something?

In my opinion it would be very useful and practical to be
able to use different projections for the reference map and
the main map.
This would, of course, in many cases lead to non-rectangular
outlines on the reference map, so one would have to determine
an appropriate level of detail for the outlines (from linear
interpolation between the four corner points to a smooth
rendering of the exact boundary curves). The lowest level
of detail would imply four coordinate transformations while
a high level of detail would lead to lots of coordinate
transformations.

The only effect I believe this would have on other elements
is that "EXTENT" in the reference map object would have to
be specified in the reference map coordinate system.


-- 
Håvard Tveite                      Phone:  +47 64948857
Department of Mapping Sciences     Fax:    +47 64948856
Agricultural University of Norway
POBox 5034, N-1432 Ås, NORWAY    http://www.nlh.no/ikf/



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