NAME
v.prune - Prunes points from binary GRASS vector
data files.
(GRASS Vector Program)
SYNOPSIS
v.prune
v.prune help
v.prune [-i] input=name
output=name thresh=value
DESCRIPTION
The GRASS program v.prune allows the user to
remove extra points from a vector file. This allows users
to reduce disk space required by a vector file and still
have data accuracy within a given tolerance.
OPTIONS
Flag:
- -i
- The pruning threshold value is specified in map inches,
rather than in data base units on the ground.
Parameters:
- input=name
- Name of binary GRASS vector file containing data to be pruned.
- output=name
- Name to be assigned to new, pruned vector output file.
- thresh=value
- Threshold value used for pruning.
The program will be run non-interactively if the user
specifies all parameters and (optionally) the -i flag
on the command line, using the form:
-
v.prune [-i] input=name
output=name thresh=value
If the user simply types v.prune without specifying
program arguments on the command line, the program will
prompt the user to enter parameter values.
NOTES
The threshold value is the same as the
v.digit pruning threshold.
This is specified in data base units on the ground (e.g.,
in ground meters for UTM data bases). The threshold can
also be specified in inches on the map, and the program
will convert these to data base ground units using the
scale in the vector file. If you specify the
scale in map inches rather than in ground units, you must
specify that inches are used by setting the -i
flag. The input vector data layer will be read and the
resultant pruned vector data layer will be placed into a
newly created output file whose name is specified by the
user, leaving the original vector map unchanged.
The pruning algorithm throws away redundant points within
the specified threshold. It works on each vector
separately, working from node to node. It does not change
the position or number of nodes.
SEE ALSO
v.digit,
v.in.ascii
AUTHOR
Dave Gerdes, U.S.Army Construction Engineering
Research Laboratory