[GRASSLIST:3206] Re: GRASS-Python, or, Alber's algorithm?

[Eric G. Miller]

On Sun, Feb 24, 2002 at 10:49:54PM -0800, RJ wrote:
> Hello GRASS users,
> My only GIS need is very specific, but, so far, confounding.
> I've been trying for a while to find software or an algorithm to convert an
> Alber's conical equal-area NLCD file to lat/long raster so that it can be
> registered with the San Diego area DEM.
> The DEM is programmatically very easy to work with and I have written a few
> small GUI utilities that use it; the goal is for my program (in wxPython) to
> be able to look up both elevation and land use with the simple
> lat/long-row/column correspondence of the DEM.
> Is there a GRASS-Python binding for reprojection/translation, or at least a
> class/method that I could learn the algorithm from?
> So, essentially, how does one calculate the lat/long position of a given
> NCLD pixel or byte offset?

I don't know what NCLD refers to.  But, if you just want to project
coordinates, you can use something like the proj4 library.  If you
actually want to reproject the raster, then you can use r.proj or
i.rectify.  There's no GRASS/Python binding (that I'm aware of).
Most of GRASS is really "stand-alone" programs (there are expectations
about the environment).

> None of the free/shareware software that I have installed (10+) will do the
> raster file conversion, and I would prefer to use the algoritm anyway.
> Web-based info on the algorithms is very sparse.

GRASS is pretty strong on raster data.  But you'll have to import it
first...

> Any help or pointers to sources would be greatly appreciated!

You find this list, so I assume you saw where tutorials on such are
on the website(s).

> "Dammit Jim, I'm a Python programmer, not a GIS Guru!"
> [Bones, episode #74]

And I'm a GIS guru, not a programmer...

-- 
Eric G. Miller <egm2 at jps.net>