[OSRS-PROJ] Problem with projecting 180,90 using Mercator

Benjamin Wragg bwragg at tpg.com.au
Tue Jul 1 19:37:18 EDT 2003

Hi list,

I'm currently using PostGIS (which uses the proj4 library) to convert
and store some spatial data. I receive 4 coordinates in lat/long which
define the extents of a hardcopy map. I use these coordinates to create
a PostGIS feature. The next step I need to do is convert the feature to
the desired coordinate system. This works great for most features but
I've found that if a hardcopy map has been specified with coordinates
like -180,-90,180,90 (a typical map of the world) the transformation
crashes. I've questioned the PostGIS list and Paul Ramsey suggested
running cs2cs manually which is what PostGIS essentially uses for
transformations. When I run the following:

	cs2cs +proj=latlong +ellps=WGS84 +to +proj=merc +lon_0=150.0
	180 90

I get:

	* * 0.00

If I pass in any other coordinate I get values back OK.
So why is -180,-90,180,90 not being projected? Any suggestions?


Benjamin Wragg

PROJ.4 Discussion List
See http://www.remotesensing.org/proj for subscription, unsubscription
and other information.

More information about the Proj mailing list