[mapserver-users] is this reorientation possible?

[Alan Swithenbank]

Hi,

I've done some looking at the docs and some googling, but, haven't
yet clearly determined if the kind of map reorientation I want to do
is possible in some reasonable way.

Basically I have a perl mapscript server setup that produces an
html form user interface page having a version of the canonical
"Blue Marble" world map image. The interface is used to query our
database, and I use query results to generate shapefiles to plot
marine predator tracks from satellite tagged animals over the map
image. That all is working fine.

My problem is many of the animals cross the +/-180 degrees longitude
line and on an image with west and east boundaries of -180 and +180
that crossing causes track connecting lines to run across the entire
world map image. (That isn't a suprise. I deal with that issue all
the time in other systems.)

Ideally I'd like to be able to reorient the world map so that depending
on whether we're working in the Atlantic I can select to use 0 degrees
as the map center, or if we're working in the Pacific I can select to use
-/+180 degrees as the map center, and get track positions to plot
properly. Barring that, is there a feature I can turn on that, in
creating the final shapefiles, understands not to make the -/+180
cross connection segment in a track? (I'm using the perl Geo::Shapelib 
module to create shapefiles.)

I know I can do those things in my own perl code with position
translations and track segment restrictions, but, am hoping to not
have to work quite that hard. And, I'm afraid my current knowledge of
mapserver/perl-mapscript is barely out of the code pattern matching
phase...;^)

If someone could point me in the general direction of information on
dealing these issues with respect to mapserver/perl-mapscript, I'd
really appreciate it.

thanks!

Alan Swithenbank
Research Progammer
Tagging of Pacific Predators Project
Hopkins Marine Station of Stanford University
120 Ocean View Blvd.
Pacific Grove, CA
93950