A technician in my lab has a map of a forest site, with the
locations of 5000 or so trees on it. She wants to digitize
this, with a point for each tree. She already has a file of
each tree's number and its various characteristics, in tabular
text form. What we want from GRASS is the x,y coordinates for
each tree. The plan is to digitize all the points, in sequence,
from tree 1 to 5000. But it would be best if, while digitizing,
the trees were autolabelled 1 to 5000, so that, as she goes, she
can easily see if she misses a tree, or double enters one.
Problem: It seems the autolabel option in v.digit2 doesn't have
an incrementing autolabel mode; it simply labels all the points
with attribute value "1" or "0" or whatever value is currently
set. V.alabel will incrementally label areas, but not point data.
Question: What is the most convenient way for us to a) keep track
that she isn't missing points or getting them out of order, and b)
get the points labelled correctly?
So far it seems to me our only option is to be bloody careful that
the total number of points digitized, as she goes along, is equal
to the number of the last tree digitized, and then, at the end, use
the UNIX cut and paste commands to make a dig_atts file with the
correct numbers tacked on the end. My second option is to edit
v.alabel to make a v.plabel program or some such. The third option
would be (yuck) to edit the v.digit2 source.
Any better ideas?
Tim.
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Tim Martin * The conception of illocutionary force
Spatial Information Systems * as a unitary disambiguating context for
University of Alberta * the semantic content produces special
martin@ulysses.sis.ualberta.ca * tangles in the case of certain kinds
(403) 492-6586 * of negation. -Cronen et al., 1990
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