This comes from ArcGIS Help 10.1: One method to calculate the standard parallels is by determining the range in latitude in degrees north to south and dividing this range by six. The "one-sixth rule" places the first standard parallel at one-sixth the range above the southern boundary and the second standard parallel minus one-sixth the range below the northern limit. There are other possible approaches. Try : standard_par1=23d, $ standard_par2=-3d, $

Hi, thank you for your answer. Surely, the fix to the issue can't be to change the map projection. I am aware of the 1/6's rule for the standard parallels. I didn't think the order mattered, but I checked and it seems that IDL doesn't care. The standard parallels should be placed slightly within the boundary of the area of interest to balance distortions towards the center of the projection and towards the poles. Thus, the map projection is valid beyond the standard parallels but with increasing distortions towards the poles. What seems to happen in IDL (and not other software, e.g. ArcGIS) is that if the second standard parallel is 0 or -0, then the map display seems limited to the northern hemisphere. If the SP is set to a tiny negative value then the map displays as expected. The following code works, so I'm probably going to use this trick for now. But there must be a better solution... mp = map('albers equal area', semimajor_axis=6378137.d, $ semiminor_axis=6356752.3d, standard_par1=25d, standard_par2=-10d^(-6), $ center_longitude=110d, center_latitude=-15d, $ false_easting=0d, false_northing=0d, limit=[-10,90,30,140]) m1 = mapcontinents( /countries)