NAME
v.mkquads - Creates a GRASS vector map layer
and/or sites list
and/or geographic region definition file
for a USGS 7.5-minute quadrangle.
(GRASS Vector Program)
SYNOPSIS
v.mkquads
v.mkquads help
v.mkquads [-esrvx] map=name
DESCRIPTION
There are three types of output available from the GRASS
program v.mkquads:
- a vector map of all the full USGS quadrangles that will fit within the
boundaries of the current geographic region.
- a GRASS sites list containing the corner coordinates of
each of these quads.
- GRASS geographic region definition files
associated with each of the quads created.
A quad is defined as the area covered by a USGS
7.5-minute (1:24,000) map. This program is useful for
managing a GRASS data base LOCATION which contains a number
of quads which are to be patched together.
Flags:
- -e
- Encompass current geographic region with quads
(rather than only creating those quads that lie inside of
the geographic region).
Use of this option will affect all output options.
- -s
- Create a GRASS sites list file.
The sites list will contain all the corner coordinates of all the
full quads that can be built in the current geographic region.
The sites list file can then be displayed using the
d.sites
program.
- -r
- Create region file(s): quad.1 quad.2 ...
The program will generate a separate geographic region
definition file for each quad; each of the geographic
region files created will have the prefix quad.
with some number attached to it. For example, if only one
quad were created, the geographic region file
quad.1 would also be created in the
windows directory under the user's current
mapset. To make the program-generated geographic region
definition file quad.1 your current
geographic region setting, run the GRASS
g.region program.
- -v
- Create vector file (default).
Only full quads will be created. The binary vector map
layer output is placed under the user's dig
directory and can be used like any other vector map layer.
Run v.support to
build the topology information for the vector map before
using v.mkquads map layer outputs in the
v.digit program. Since
the quads are computer-generated, the corner coordinates
will be exact. This simplifies digitizing if one or more
quad sheets will have to be brought together for a data
base, because all of the quad corner points to be joined
will be guaranteed to match.
- -x
- Create a GRASS registration (reg) file.
Parameter:
- map=name
- The name of a file to contain program output.
If the user runs v.mkquads without including
program parameter value and desired flags on the command
line, the program will prompt the user for the above
information using the standard GRASS interface described in
the manual entry for
parser.
NOTES
All output options can be used on the command line at the
same time. A listing of all the quad points in
latitude/longitude and UTM coordinates will be displayed
each time the program is executed. The spheroid being used
for the lat/lon to UTM conversions is clark66.
BUGS
Currently, this program only works for GRASS locations in a
Universal Transverse Mercator (UTM) coordinate system (in
meters). There are no guarantees that v.mkquads
will function properly if a quadrangle crosses UTM zones.
This program has not been tested outside the northwest UTM
quadrant.
SEE ALSO
d.sites,
g.region,
v.digit,
v.mkgrid,
v.support
and
parser
AUTHORS
Michael Higgins,
U.S. Army Construction Engineering
Research Laboratory
Marilyn Ruiz, U.S. Army Construction Engineering
Research Laboratory