[mapserver-users] setting projection based on zoom

[Jensen, Hannah ERDC-CRREL-NH]

Hi, all.  I would like to be able to change projections based on how far the
user is zoomed in.  For example, if they start out looking at the US in
Lambert Azimuthal Equal Area but zoom in on Alaska, the map should display
the zoomed in area in UTM zone 6.  I'm hoping to be able to do this with CGI
variables, but maybe that's not possible.  If I pass in the projection
parameters and the map extent (in the new projection units) like so:

http://myserver/cgi-bin/mapserv34g?map=../html/usamap/tiger.map&mode=browse&
map_projection=proj=utm,zone=6&mapext=415087+7115646+546659+7214763

it works fine.  But since I don't know the map extent in the new projection
before conversion, what variables should I pass to properly define the map
extent?  Can I somehow tell it to calculate the new extent based on the old
one?  Is there a better way to do this?  Thanks in advance for any
info/advice...



Cheers,
Hannah