[GRASS5] difficulties with r.proj (was: Temporal data in GRASS?)

[Carl Worth]

Carl Worth writes:
 > Markus Neteler writes:
 >  > g.region rast=imported_map
 > 
 > Whoops... that was my problem. Somehow I thought my elevation and map
 > data were for the exact same region, but I guess not. I feel foolish.

I'm making headway, but I'm also causing new problems.

My two datasets *are* both for the same region -- the problem was that
the data were in two different projections, (UTM vs. Albers Equal
Area). I've now got each one imported into its own location and I can
view each one separately just fine.

But, of course, I'd like to see them together, so I need to transform
one into the projection of the other. r.proj looks to fit the bill
exactly, but I'm getting the following:

	GRASS > r.proj input=amap location=albers
	cannot initialize pj
	cause: projection not named
	ERROR: Can't get projection key values of output map

My current location seems to have a well-defined projection:

	PROJECTION:	1 (UTM)
	DATUM:		NAD27
	ELLIPSOID:	clrk66

so what could I be missing?

...

Hmmm... I'm stepping through r.proj in gdb now. It looks like if
PROJ_INFO has one of "name", "tinit", or "sproj" that I might get past
the current problem. So what would I name my projection? Maybe "name:
utm". With that I now get:

	cannot initialize pj
	cause: major axis or radius = 0 or not given
	ERROR: Can't get projection key values of output map

Now it appears to be trying to load some projection parameters based
on the name of my projection. It's trying to look in PROJ_LIB, (which
is not set). I'm feeling like I must not have installed something...

Hmm... programmers manual talks about PROJ4. Do I have to install that
separately?

I'll keep poking.

Any light that could be shed would be most appreciated.

-Carl (Who is anxious to start contributing rather than continually
 exposing his ignorance in public forums)

-- 
Carl Worth                                        
USC Information Sciences Institute                 cworth at east.isi.edu
3811 N. Fairfax Dr. #200, Arlington VA 22203		  703-812-3725