Removing Sites

GRASS GRASS user
1

From grass-lists-owner@max.cecer.army.mil Fri Jan 21 08:16:37 1994
From: a16dhoover@attmail.com (David Hoover )
Date: 21 Jan 94 16:00:51 GMT
Sender: grass-lists-owner@max.cecer.army.mil
Reply-To: grassu-list@max.cecer.army.mil
To: grassu-list@max.cecer.army.mil, gis@attmail.com
Cc: a16pbiggam@attmail.com (Peter F Biggam)
Phone: +1 208 334 1525
Subject: Removing Sites
Content-Type> : > text>
Content-Length: 774

Greetings from Idaho!

I have a coverage with about 7,000 polygons and about 21,000 sites. I would
like to be able in GRASS 4.0 to delete all of the sites while still keeping
all the polygons and their associated labels. I don't recall any GRASS 4.0
commands like v.rm.sites or something similar that would do it all for me.

Any suggestions?

(I thought about converting it to an ASCII file and then deleting all lines
with "P 2" in it, but don't know enough about ed or vi to delete that line
and then the next two lines that contain the coordinates for the degenerate
line.)

P.S. Yes, fellow SCS readers, this is NRI data I'm dealing with!

Thanks in advance

David Hoover
Cartography and GIS Section
USDA-SCS, Idaho State Office
a16dhoover@attmail.com
208-334-1525

You are on the right track. In the dig_ascii files, a "P" means a "live"
point, ("A" means area, "L" for line). If you change a "P" to "p" it is the
same as erasing it. Lines removed during v.digit show up in the dig_ascii
file with an "l".

Assuming you know NO vi here are the instructions:

  vi filename

  type :g/^P/s//p/g
(this should appear at the bottom of your screen. It substitutes for all
P that are at the beginning of a line with a p.)
    ZZ (to quit)
    :q! (to quit with out changing if you blew it)

Then reimport it to GRASS dig format.

Sue Huse
CEDR - REGIS
University of California, Berkeley