[Proj] inverse projecting ASCII data

Ken Mankoff mankoff at gmail.com
Tue Oct 16 00:48:18 EDT 2007

Hi List,

I'm completely new to proj and fairly new to projections in general 
at this level of detail, although I've been making maps for years 
with higher level tools (IDL).

I now have an ASCII file centered on the south pole. I'd like to 
inverse project it to a simple cylindrical gridded data set of, for 
example, 1x1 degree latitude longitude boxes (eventual goal: Google 
Earth layer that requires pole at edgcm of image).

I've been reading the man page for invproj but am not able to get 
far at all. I don't know much about the data but I do know this:

* Polar Stereographic, 71S as true lat scale
* Grid is 5km
* I know the number of rows and columns of the input ASCII file
* And that "xllcorner: -2713600" and "yllcorner: -2304000"
   but I don't know what these mean

I've come up with this mostly from an old archive post:

invproj +proj=stere +lon_0=0 +lat_0=-90 +lat_ts=-71 proj.test.in > proj.test.out

But don't fully understand the output,  which looks like this:

> 135dW   89d52'11.473"S -9999 ....
> 135dW   89d52'11.473"S -9999 ...
and then suddenly
> 0dE     90dS 0 0 ...

Any help greatly appreciated.



Sent from Antarctica: http://pace.edgcm.columbia.edu

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