[Proj] Oblique Cyl Eq Area - confused

William K woklist at charter.net
Fri Jul 1 15:16:18 EDT 2005

I want to set up a map with the Oblique Cylindrical Equal Area  
projection (ocea).  I couldn't find much info on parameters needed  
and the effects of them.    From what I found in the USGS projections  
book I need two points for the oblique line (lat_1, _2, lon_1, _2).   
Simple enough.  Yet I get projected coordinates in the trillions!   
It's not an easting/northing problem - I get +/- trillions around the  
center of the projection.

this is what I used (Australia/SE Asia region):

proj +proj=ocea +ellps=sphere +lat_1=-45 +lat_2=22.5 +lon_1=180  

Changing the distance between the oblique points seems to affect the  
projection a bit - instead of at the limits of the area of interest,  
if I make them say 1/10 of that apart, the coordinates go down by up  
to a trillion.

Anyone have any definite info on setting up this projection?  If it's  
normal, what do those large numbers really mean (if not meters)?  Did  
I miss a parameter?

William Kyngesburye <kyngchaos at kyngchaos.com>

"History is an illusion caused by the passage of time, and time is an  
illusion caused by the passage of history."

- Hitchhiker's Guide to the Galaxy

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