NAME¶
g.gisenv - Outputs and modifies the user's current GRASS variable
settings.
KEYWORDS¶
general, settings
SYNOPSIS¶
g.gisenv
g.gisenv help
g.gisenv [-
sn] [
get=
VARIABLE]
[
set=
VARIABLE=value] [
store=
string]
[--
verbose] [--
quiet]
Flags:¶
- -s
-
Use shell syntax (for "eval")
- -n
-
Don't use shell syntax
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- get=VARIABLE
-
GRASS variable to get
- set=VARIABLE=value
-
GRASS variable to set
- store=string
-
Where GRASS variable is stored
Options: gisrc,mapset
Default: gisrc
DESCRIPTION¶
When a user runs GRASS, certain variables are set specifying the GRASS data
base, location, mapset, peripheral device drivers, etc., being used in the
current GRASS session. These variable name settings are recognized as long as
the user is running a GRASS session.
OPTIONS¶
No prompts are given to the user when running
g.gisenv. If run without
arguments,
g.gisenv lists all of the user's current GRASS variable
settings. Results are sent to standard output, and may look like this:
GISDBASE=/opt/grassdata/
LOCATION_NAME=spearfish
MAPSET=PERMANENT
In this example, the full path name of the user's current location (i.e.,
$LOCATION_NAME) is /opt/grassdata/spearfish, and the full path name of the
user's current mapset (i.e., $MAPSET) is /opt/grassdata/spearfish/PERMANENT.
If the user specifies a
variable_name on the command line (e.g., g.gisenv
MAPSET), only the value for that particular GRASS variable is output to
standard output. Possible variable names depend on the user's system, see
variables list for details.
While other variables may be associated with each GRASS session (e.g.,
GRASS_GUI, GIS_LOCK, and other variables), those stated below are essential.
- GISDBASE
-
The $GISDBASE is a directory in which all users' GRASS data are stored.
Within the $GISDBASE, data are segregated into subdirectories (called
"locations") based on the map coordinate system used and the
geographic extent of the data. Each "location" directory itself
contains subdirectories called "mapsets"; each
"mapset" stores "data base elements" - the
directories (e.g., the cell, cellhd, vector, etc., directories) in which
GRASS data files are actually stored.
- LOCATION_NAME
-
The user must choose to work with the data under a single GRASS location
within any given GRASS session; this location is then called the
current GRASS location, and is specified by the variable
$LOCATION_NAME. The $LOCATION_NAME is the GRASS data base location whose
data will be affected by any GRASS commands issued during the user's
current GRASS session, and is a subdirectory of the current $GISDBASE.
Each "location" directory can contain multiple
"mapset" directories (including the special mapset PERMANENT).
Maps stored under the same GRASS $LOCATION_NAME (and/or within the same
MAPSET) must use the same coordinate system and typically fall within the
boundaries of the same geographic region (aka, "location").
- MAPSET
-
Each "mapset" contains a set of maps relevant to the
$LOCATION_NAME directory in which it appears. Each $LOCATION_NAME can
contain multiple mapsets. (Mapsets which fall under the same
$LOCATION_NAME all contain data geographically relevant to the
$LOCATION_NAME, and all store data in the same map coordinate system.
Frequently, maps are placed into different mapsets to distinguish file
ownership - e.g., each user might have his own mapset, storing any maps
that he has created and/or are relevant to his work.) During each GRASS
session, the user must choose one mapset to be the current mapset;
the current mapset setting is given by $MAPSET, and is a subdirectory of
$LOCATION_NAME. During a single GRASS session, the user can use available
data in any of the mapsets stored under the current $LOCATION_NAME
directory that are in the user's mapset search path and accessible by the
user. However, within a single GRASS session, the user only has
write access to data stored under the current mapset
(specified by the variable $MAPSET).
Each "mapset" stores GRASS data base elements (i.e., the directories
in which GRASS data files are stored). Any maps created or modified by the
user in the current GRASS session will be stored here. The $MAPSET directory
PERMANENT is generally reserved for the set of maps that form the base set for
all users working under each $LOCATION_NAME.
Once within a GRASS session, GRASS users have access only to the data under a
single GRASS data base directory (the
current GRASS data base,
specified by the variable $GISDBASE), and to a single GRASS location directory
(the
current location, specified by the variable $LOCATION_NAME).
Within a single session, the user may only
modify the data in the
current mapset (specified by the variable $MAPSET), but may
use
data available under other mapsets under the same $LOCATION_NAME.
All of these names must be legal names on the user's current system.
NOTES¶
The output from
g.gisenv when invoked without arguments is directly
usable by Bash. The following command will cast each variable into the UNIX
environment:
eval `g.gisenv`
This works only for
Bash. The format of the output is not compatible with
other UNIX shells.
GRASS Debugging¶
To print debugging messages, the variable DEBUG must be set to level equal or
greater than 0:
g.gisenv set="DEBUG=3"
Levels: (recommended levels) 0 - silence 1 - message is printed once or few
times per module 3 - each row (raster) or line (vector) 5 - each cell (raster)
or point (vector) To disable debugging messages, DEBUG must be set back to 0:
g.gisenv set="DEBUG=0"
SEE ALSO¶
g.access, g.filename, g.findfile, g.mapsets
See also variables list
AUTHOR¶
Michael Shapiro, U.S.Army Construction Engineering Research Laboratory
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
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