NAME
v.alabel - Bulk-labels unlabeled area features in
a binary GRASS vector file.
(GRASS Vector Program)
SYNOPSIS
v.alabel
v.alabel help
v.alabel [-i] map=name
[value=value]
DESCRIPTION
v.alabel allows the user to bulk-label currently unlabeled polygons
(area features) in a binary GRASS vector file (i.e., a dig file).
The user must run
v.support
on the vector file before running
v.alabel if any modifications have been made to the file
since the last time
v.support
was run on it, to ensure that
all area features are properly identified in the file topology.
The user must also run
v.support
on the vector file after v.alabel is run for
labeling changes to be made evident.
v.support
builds GRASS support files for (binary) GRASS vector
data files. These support files supply topology (dig_plus)
and category (dig_att) information that are needed by other GRASS
programs (e.g., by
v.digit,
v.to.rast, etc.).
OPTIONS
Program parameters and flags have the following meanings.
Flags:
- -i
- Label areas incrementally. For each unique, unlabeled
polygon in the vector file, increment the category value by
one, starting from the initial user-assigned
value.
Parameters:
- map=name
- Name of binary GRASS vector data file whose unlabeled areas
are to be labelled. This map layer must exist in the
user's current GRASS mapset.
- value=value
- The category value to be assigned to all unlabeled areas in the
vector map layer. If the -i flag is set, v.alabel
will increment the initial value by one for each unique unlabeled
polygon in the vector map.
Default: 1
The user can run this program non-interactively by specifying parameter
values (and optionally, the flag setting) on the command line.
Alternately, the user can simply type the command v.alabel on
the command line. In this event, the program will prompt the user to
enter parameter values and flag settings.
NOTES
A dig_plus file must be created for each imported vector map
before it can be used in post-GRASS 3.0 versions of digit
(now referred to as v.digit).
Topological information for GRASS vector files can also be
built using option 4 of the
v.import program.
The user can bulk-label unlabeled line features in a
binary vector file using
v.digit.
SEE ALSO
v.digit
v.import
v.in.ascii
v.prune
v.support
v.to.rast
AUTHORS
Dave Gerdes, U.S.Army Construction Engineering
Research Laboratory