Need Help developing WGS84 ("Web") Mercator Projection for GrADS

[Pablo Romero]

Hello,
Im currently reviewing, testing, & attempting to change the grads2.0 source code in order to add a Mercator projection.
For those who are familiar in GrADS code/development, I could please use some assistance.
I've narrowed the projection routines to the gwxmap.c source file.
 
I need help with:
2) how to create the "scaling" functions to correctly adjust the x,y values for the grads (internal) grid
1)determining in how many different places the scaling function needs to be applied, 
  (*since it seems there are a few different routines throughout all of the source code files where the
   scaling is performed)
3)question: once the projection routine is implemented, it *should* take care of correctly scaling&drawing everything, including maps, grids, shapefiles (using shapefile extension), symbols, etc., is this correct?
 
The functions for transforming from lat/lon to x,y are fairly simple: 
http://en.wikipedia.org/wiki/Mercator_projection 
x=lon; 
longitude remains unchanged
 
y=ln(tan((pi/4)+(lat/2))); 
latitude is variable
 
so, I believe the key is just setting up the transformation functions and correctly referring to them throughout the source code.
 
Most other graphics packages already include a Mercator projection, and it gets used alot for web mapipng/tiling, such as google earth & MS Virtual Earth.
Grads needs this...
 
Those interested, please email me.
Thanks,,
P.Romero
 
 
 
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