[GRASSLIST:3884] Re: Projection and m.in.e00

[Ben Logan]

On Sat, Jun 15, 2002 at 11:20:01PM +0200, Markus Neteler wrote:
> [...]
> > Apparently AVECE00 and AVCE00 are the same package.  I also found the
> [...]
> 
> Use this utility to turn the e00 file into a binary ARC coverage and
> then 'ogr2ogr' (from GDAL) on that to generate a SHAPE file.

Okay, thanks.  If I decide to use the data with Mapserver, I'll need
to convert to SHAPE, since it doesn't understand e00. However...
 
> But I am not convinced that this is a good idea, since E00 is better
> than SHAPE. It may be recommended to try harder the E00 import which
> is known to be functional.

I see your point.  Especially since I haven't yet upgraded to pre4,
and v.in.shape is busted in pre3.  Soooo, below I've included the
procedure I go through in order to import an e00 file.  The e00 file
is part of the Southern Appalachian Assesment (SAA) Database, and is
located at
http://sunsite.utk.edu/samab/data/saa1/saa_100k/boundary.zip.  It is
approximately 219Kb.  Perhaps one of you can see what I'm doing wrong,
or try it yourself to see if you have the same problem.  I know that's
a bit of trouble, but I'd really appreciate it. :)

First, I crank up Grass and use an existing location (nationalatlas)
which is in lat/lon projection.  I also use an existing mapset
(states).  Here's the PROJ_INFO file file from the PERMANENT mapset
looks like:

name: Latitude-Longitude
datum: nad83
dx: 0.000000
dy: 0.000000
dz: 0.000000
proj: ll
ellps: grs80

Now I'll import the e00 file (boundary.e00) into a new mapset to avoid
the problems mentioned in the m.in.e00 manpage (the 'saa' mapset
doesn't exist yet):

GRASS:~/grass5.0/saa > m.in.e00 input=boundary.e00 mapset=saa verbose=1 logfile=out.log

Here's the contents of 'out.log' after the above command:

"boundary.e00" successfully opened
ARC  2
Arc coverage : 62 arcs (26137 points)
CNT  2
LAB  2
Label table : 1 entries
PAL  2
PAL : 2 polygons (125 arcs referenced)
TOL  2
SIN  2
LOG  2
PRJ  2
IFO  2
BOUNDARY.BND XX 4 16 1
INFO table .BND
Creating region
BOUNDARY.PAT XX 7 26 2
Writing cats file "boundary.hectares_c"
Writing cats file "boundary.acres_c"
Writing cats file "boundary.saa"
BOUNDARY.TIC XX 3 12 380
getinfo returns Cover_type = 2
EOS
Creating dig_att(L) file "boundary"
Updating dig_att(A) file "boundary"
Import of boundary complete

Now I'll quit Grass and restart in the new 'saa' mapset (I guess it
isn't strictly necessary to exit Grass, but ...).

 From the new mapset, I 'cd $LOCATION'.  Here's what the WIND file
looks like:

proj:       99
zone:       0
north:      730721.94
south:      16980.227
east:       353657
west:       -420133.16
cols:       21666124
rows:       19984768
e-w resol:  0.03571429
n-s resol:  0.03571429

Well, clearly this is all wrong if in fact the source e00 was in
lat/lon projection.  So I used g.region to set the current region to
the default value for the nationalatlas location.  That doesn't fix
the map, though.  v.info still shows the bad numbers in the map:

[...]
    Projection: Latitude-Longitude (zone 0)
              N:     730722    S:      16980
	            E:     353657    W:    -420133
[...]

I thought perhaps v.support would fix the problem (I'm probably
showing my ignorance here...does v.support ever modify that type of
info?)  I 'cd $LOCATION/dig_cats', and 'mv boundary.saa boundary'.  Then I
run 'v.support boundary' without any errors.

However, that didn't change anything--v.info still shows that the map
boundaries are whacked out.  d.rast doesn't show anything when I try
to display this map...which I would fully expect with those
boundaries.

I then tried running 'g.region vect=boundary', but it gives this
message (which is also quite understandable):

ERROR: Invalid region: North must be north of South

And that's where I'm stuck. :(  Does anyone see what I'm doing wrong?

Thanks,
Ben

-- 
Ben Logan: ben at wblogan dot net
OpenPGP Key KeyID: A1ADD1F0

"I teleported home one night
With Ron and Sid and Meg.
Ron stole Meggie's heart away
And I got Sidney's leg."

- A poem about matter transference beams.