[GRASSLIST:4677] robinson projection

[Ian MacMillan]

Hi all again, I have a weird problem.  I am trying to make a world map 
using the robinson projection.  I have projected in a raster map of the 
world into this location, and instead of obtaining the nice oval-ish 
shape we are used to, the new raster is a rectangle with areas at the 
edges duplicated.  The edges are distorted as they should be, but there 
is no way to determine where the edges of the original map lay.  I 
figured this is ok if I could project in a vector box of the world 
(from a latlong location), and just use that as a mask.  Trouble is 
that when I project in a vector area with bounding coordinates of n=72 
s=-72 e=180 w=-180 in latlong space, it comes into the Robinson 
location as a box, not an oval-ish shape.  This doesn't make any sense 
to me.  Is this a problem with proj.4?  Or is it impossible to 
delineate lines of longitude in the Robinson projection (measurement 
units are meters)?

Thanks for any input y'all might have,
Ian