GRASS-Wiki - User contributions [en]

GRASS in Debian

2009-11-26T17:20:28Z

⚠️FrancescoLovergine:

Grass in Debian is maintained by the [http://pkg-grass.alioth.debian.org/cgi-bin/wiki.pl DebianGis] Team. Some modifications to the code base are due to the [http://www.debian.org/doc/debian-policy/ Debian Policy] compliancy required by the distribution. You can find that the Debian stable version is generally older that the current stable version of Grass: that is due to the releasing and maintainance roadmap of Debian.

Unofficial newer packages for Debian stable can be available by third parties. Generally you can mix those packages with [http://www.backports.org/ backports.org] packages in order to work on a more up-to-date workstation, but the result can be less stable and coherent than the official release, because they are generally built using unstable snapshots and sometimes packages are not compatible each other. This is due to the binary nature of the packages and policy evolution.

GIS Concepts

2009-05-29T18:28:29Z

⚠️FrancescoLovergine: /* Map projections */

== Geodesy and Cartography ==
=== Background material ===

* [http://oceanservice.noaa.gov/education/kits/geodesy/welcome.html An introduction to Geodesy] from NOAA
* [http://en.wikipedia.org/wiki/Geodesy Wikipedia's Geodesy entry]
* [http://en.wikipedia.org/wiki/GIS Wikipedia's GIS entry]
* [http://www.nga.mil/portal/site/maritime/ Bowditch's American Practical Navigator] - (especially chapter 2)
* [http://earth-info.nima.mil/GandG/publications/ NGA Geodesy and Geophysics publications]
* [http://www.ordnancesurvey.co.uk/oswebsite/gps/information/coordinatesystemsinfo/guidecontents/index.html UK Ordnance Survey primer on coordinate system concepts] ([http://www.ordnancesurvey.co.uk/gps/docs/A_Guide_to_Coordinate_Systems_in_Great_Britain.pdf PDF])

=== Map projections ===

* [http://www.asprs.org/resources/grids/ ASPRS Grids and Datums]: detailed descriptions of national projections
* [http://www.mapref.org/ MapRef] - The Collection of Map Projections and Reference Systems for Europe
* [http://www.remotesensing.org/geotiff/proj_list/ Projections Transform Lists] (PROJ4)
* [http://www.dmap.co.uk/utmworld.htm UTM Zones]

EPSG:
* [http://www.epsg.org EPSG projection codes]
* [http://www.epsg-registry.org/ EPSG database search]
* [http://spatialreference.org/ Spatialreference community portal]

Projection galleries:
* [http://www.progonos.com/furuti/MapProj/CartIndex/cartIndex.html Map projection concepts] by Carlos Furuti
* [http://www.csiss.org/map-projections/index.html Map projection gallery] by Paul Anderson ([http://www.galleryofmapprojections.com/ old link])


=== Map datums ===

An extra calculation is needed when re-projecting maps and data between
two different co-ordinate systems (in addition to the re-projection) if
the two co-ordinate systems are based on different models of the
curvature of the earth. E.g. OSGB36 uses the Airy ellipsoid and WGS84 uses the WGS84 ellipsoid, which have slightly different sizes and shapes. The error is not large - generally a few hundred metres at most on the ground.
The datum transformation parameters describe this adjustment
mathematically.

As the transformation between any two datums is approximate and varies by location, different sets of parameters are often offered to give improved accuracy in different regions of a country. In general there is no one "correct" set of transformation parameters - indeed the accuracy changes over time due to tectonic movements in the Earth.

* [http://sourceforge.net/mailarchive/forum.php?thread_name=1190060064.27461.57.camel%40blackpad&forum_name=jump-pilot-devel A brief history of map datums] for the layman
* [http://www.colorado.edu/geography/gcraft/notes/datum/datum.html An introduction to geodetic datums] by Peter Dana
* [http://home.online.no/~sigurdhu/WGS84_Eng.html How WGS 84 defines the Earth]
* A discussion of [http://www.linz.govt.nz/geodetic/conversion-coordinates/geodetic-datum-conversion/nzgd1949-nzgd2000/index.aspx 3-term, 7-term, and NTv2 grid datum transformations] by Land Information New Zealand
: (besides the web page have a look at the PDF fact sheet and guide linked therein)


==How GRASS deals with geodetics==

As far as GRASS is concerned, an ellipsoid and a spheroid are the same thing, and ellipsoid is the prefered name.

As far as GRASS is concerned, a datum is made up of an ellipsoid and an origin.
Setting a datum is optional, but highly recommended.

GRASS uses a modified version of the [http://proj.maptools.org PROJ.4] library.

=== Modules controling a location's map projection ===
* [http://grass.osgeo.org/grass64/manuals/html64_user/g.proj.html g.proj] help page
* [http://grass.osgeo.org/grass64/manuals/html64_user/g.setproj.html g.setproj] help page

=== Modules for reprojecting GIS maps and data ===

* [http://grass.osgeo.org/grass64/manuals/html64_user/r.proj.html r.proj] for reprojecting raster maps
* [http://grass.osgeo.org/grass64/manuals/html64_user/v.proj.html v.proj] for reprojecting vector maps
* [http://grass.osgeo.org/grass64/manuals/html64_user/m.proj.html m.proj] for reprojecting a list of coordinate pairs

=== Modules for georectifying images ===

* [http://grass.osgeo.org/grass64/manuals/html64_user/r.region.html r.region] for resetting a raster map's bounds information
* gis.m GIS manager GeoReferencing tool (File menu)
* [http://grass.osgeo.org/grass64/manuals/html64_user/i.points.html i.points] and [http://grass.osgeo.org/grass64/manuals/html64_user/i.vpoints.html i.vpoints] for setting GCPs
* [http://grass.osgeo.org/grass64/manuals/html64_user/i.rectify.html i.rectify] for georectifying imagery
* [http://www.gdal.org GDALwarp] (use with gdal_translate, see the i.warp script in the wiki [[GRASS_AddOns#Imagery_add-ons|AddOns]] page)

;[[Georeferencing]]

==GIS Data types==

===Raster Data===

Data which occurs in a regularly spaced grid. e.g. a satellite image or digital terrain map. 
Region settings determine the spatial extent and resolution of the grid.

;[http://grass.osgeo.org/grass64/manuals/html64_user/rasterintro.html Raster Intro]
[[Replacement raster format]]

[[GRASS Raster Mask]]

[[GRASS raster semantics]]

===3D Raster Data (Voxel)===

A stack of 2D raster maps.

;[http://grass.osgeo.org/grass64/manuals/html64_user/raster3dintro.html Raster 3D Intro]

===Vector Data===

Data which occurs as a series of coordinates. e.g. a GPS position or coastline map. May be a point, line, area, etc in either 2D or 3D space. Generally independent of region settings.

;[http://grass.osgeo.org/grass64/manuals/html64_user/vectorintro.html Vector Intro]
[[Vectordata]]

=== Imagery Data ===
Pixelated photographic or satellite images, often imported from a
[http://en.wikipedia.org/wiki/GeoTIFF GeoTIFF] or PNG image file.

As far as the GIS is concerned this is just another raster map, but there are several modules specially tailored for rectification and processing common imagery types. e.g. ortho-photos or multi-channel [[LANDSAT]] data.

* [http://grass.osgeo.org/grass64/manuals/html64_user/imageryintro.html GRASS Imagery module introduction]

* The GRASS [[Image processing]] wiki page

===Site Data===
Old versions of GRASS (5 and earlier) treated point data separate to line and polygon data. GRASS 6 classes all vector data features the same. Convert old sites file data into GRASS 6 vector format with the GRASS 6 [http://grass.osgeo.org/grass64/manuals/html64_user/v.in.sites.html v.in.sites] or
[http://grass.osgeo.org/grass64/manuals/html64_user/v.in.sites.all.html v.in.sites.all] modules.

==Conversions between data types==

The following table is intended to catalog transformations from one type of data to another: 
''[table is currently incomplete!]''

{| border="1"
| From / To
![http://grass.osgeo.org/grass64/manuals/html64_user/rasterintro.html Raster]
![http://grass.osgeo.org/grass64/manuals/html64_user/raster3dintro.html 3D Raster]
![http://grass.osgeo.org/grass64/manuals/html64_user/vectorintro.html Vector]
|-
! Raster
| r.mapcalc
| r.to.rast3
| r.to.vect, v.sample, r.volume
|-
! 3D Raster
| r3.to.rast, r3.cross.rast
| r3.mapcalc
|
|-
! Vector
| v.to.rast, v.surf.rst, v.surf.idw
| v.vol.rst, v.vol.idw, v.to.rast3
| v.clean
|-
! Data
| r.in.*
| r3.in.*
| v.in.*
|}

==How a GRASS project is organized==

GRASS data is stored in a three level structure, the database, location and mapset. These can be found in a series of nested directories on the user's computer. All three must exist and are set at GRASS startup time.

===The Database===

The directory in which all GIS data is to be stored.

e.g. <tt>~/grassdata/</tt>

===The Location===

A ''location'' is a GRASS project consisting of an area, projection definition (or unprojected), a grouping of mapsets, all with the same projection settings. A location is a subdirectory of the GRASS ''database''.

e.g. world_lat_lon, utm_zone_59, or west_coast

A ''location'' contains one or many ''mapsets''.

===The Mapset===

A ''mapset'' contains map(s), it is a subdirectory of a ''location''.
Conceptually, if several mapsets are used in a location, they may be assigned to different users (each has one or several own mapsets to work in and cannot modify thos of other users), and/or it they are used to organize a project (''location'') by subareas or subprojects.
There are no specific organizational limitations.

There is always a PERMANENT mapset which is readable from all other mapsets within the same location. Read access to maps in other mapsets is managed with the 'g.mapsets' command or by adding the "@" symbol and mapset name (e.g. <tt>map@othermapset</tt>).

==Raster GIS Analysis==

===Simple Raster Math===

Sometimes when analyzing the relationship between two or more raster data sets, a relatively simple mathematical approach is best. One example using the {{cmd|r.mapcalc}} tool would be to look at changes between two raster data sets. By subtracting the values in these two data sets you can assume that resulting cells with a positive value have a positive change and those with a negative value have negative change. If the cell values have a zero value then there would be no change.

GRASS comes bundled with the {{cmd|r.mapcalc}} command line tool as well as a GUI interface for the tool accessible using the {{cmd|r.mapcalculator}} command. This GUI allows the user to easily assign raster maps to the variables used in the formulas and easily create mathematical strings that will result in a new raster data set containing the results.

[[Category:Development]]
[[Category:Community]]

GIS Concepts

2009-05-29T18:27:16Z

⚠️FrancescoLovergine: /* Map projections */

== Geodesy and Cartography ==
=== Background material ===

* [http://oceanservice.noaa.gov/education/kits/geodesy/welcome.html An introduction to Geodesy] from NOAA
* [http://en.wikipedia.org/wiki/Geodesy Wikipedia's Geodesy entry]
* [http://en.wikipedia.org/wiki/GIS Wikipedia's GIS entry]
* [http://www.nga.mil/portal/site/maritime/ Bowditch's American Practical Navigator] - (especially chapter 2)
* [http://earth-info.nima.mil/GandG/publications/ NGA Geodesy and Geophysics publications]
* [http://www.ordnancesurvey.co.uk/oswebsite/gps/information/coordinatesystemsinfo/guidecontents/index.html UK Ordnance Survey primer on coordinate system concepts] ([http://www.ordnancesurvey.co.uk/gps/docs/A_Guide_to_Coordinate_Systems_in_Great_Britain.pdf PDF])

=== Map projections ===

* [http://www.asprs.org/resources/grids/ ASPRS Grids and Datums]: detailed descriptions of national projections
* [http://www.mapref.org/ MapRef] - The Collection of Map Projections and Reference Systems for Europe
* [http://www.remotesensing.org/geotiff/proj_list/ Projections Transform Lists] (PROJ4)
* [http://www.dmap.co.uk/utmworld.htm UTM Zones]

EPSG:
** [http://www.epsg.org EPSG projection codes]
** [http://www.epsg-registry.org/ EPSG database search]
** [http://spatialreference.org/ Spatialreference community portal]

Projection galleries:
* [http://www.progonos.com/furuti/MapProj/CartIndex/cartIndex.html Map projection concepts] by Carlos Furuti
* [http://www.csiss.org/map-projections/index.html Map projection gallery] by Paul Anderson ([http://www.galleryofmapprojections.com/ old link])


=== Map datums ===

An extra calculation is needed when re-projecting maps and data between
two different co-ordinate systems (in addition to the re-projection) if
the two co-ordinate systems are based on different models of the
curvature of the earth. E.g. OSGB36 uses the Airy ellipsoid and WGS84 uses the WGS84 ellipsoid, which have slightly different sizes and shapes. The error is not large - generally a few hundred metres at most on the ground.
The datum transformation parameters describe this adjustment
mathematically.

As the transformation between any two datums is approximate and varies by location, different sets of parameters are often offered to give improved accuracy in different regions of a country. In general there is no one "correct" set of transformation parameters - indeed the accuracy changes over time due to tectonic movements in the Earth.

* [http://sourceforge.net/mailarchive/forum.php?thread_name=1190060064.27461.57.camel%40blackpad&forum_name=jump-pilot-devel A brief history of map datums] for the layman
* [http://www.colorado.edu/geography/gcraft/notes/datum/datum.html An introduction to geodetic datums] by Peter Dana
* [http://home.online.no/~sigurdhu/WGS84_Eng.html How WGS 84 defines the Earth]
* A discussion of [http://www.linz.govt.nz/geodetic/conversion-coordinates/geodetic-datum-conversion/nzgd1949-nzgd2000/index.aspx 3-term, 7-term, and NTv2 grid datum transformations] by Land Information New Zealand
: (besides the web page have a look at the PDF fact sheet and guide linked therein)


==How GRASS deals with geodetics==

As far as GRASS is concerned, an ellipsoid and a spheroid are the same thing, and ellipsoid is the prefered name.

As far as GRASS is concerned, a datum is made up of an ellipsoid and an origin.
Setting a datum is optional, but highly recommended.

GRASS uses a modified version of the [http://proj.maptools.org PROJ.4] library.

=== Modules controling a location's map projection ===
* [http://grass.osgeo.org/grass64/manuals/html64_user/g.proj.html g.proj] help page
* [http://grass.osgeo.org/grass64/manuals/html64_user/g.setproj.html g.setproj] help page

=== Modules for reprojecting GIS maps and data ===

* [http://grass.osgeo.org/grass64/manuals/html64_user/r.proj.html r.proj] for reprojecting raster maps
* [http://grass.osgeo.org/grass64/manuals/html64_user/v.proj.html v.proj] for reprojecting vector maps
* [http://grass.osgeo.org/grass64/manuals/html64_user/m.proj.html m.proj] for reprojecting a list of coordinate pairs

=== Modules for georectifying images ===

* [http://grass.osgeo.org/grass64/manuals/html64_user/r.region.html r.region] for resetting a raster map's bounds information
* gis.m GIS manager GeoReferencing tool (File menu)
* [http://grass.osgeo.org/grass64/manuals/html64_user/i.points.html i.points] and [http://grass.osgeo.org/grass64/manuals/html64_user/i.vpoints.html i.vpoints] for setting GCPs
* [http://grass.osgeo.org/grass64/manuals/html64_user/i.rectify.html i.rectify] for georectifying imagery
* [http://www.gdal.org GDALwarp] (use with gdal_translate, see the i.warp script in the wiki [[GRASS_AddOns#Imagery_add-ons|AddOns]] page)

;[[Georeferencing]]

==GIS Data types==

===Raster Data===

Data which occurs in a regularly spaced grid. e.g. a satellite image or digital terrain map. 
Region settings determine the spatial extent and resolution of the grid.

;[http://grass.osgeo.org/grass64/manuals/html64_user/rasterintro.html Raster Intro]
[[Replacement raster format]]

[[GRASS Raster Mask]]

[[GRASS raster semantics]]

===3D Raster Data (Voxel)===

A stack of 2D raster maps.

;[http://grass.osgeo.org/grass64/manuals/html64_user/raster3dintro.html Raster 3D Intro]

===Vector Data===

Data which occurs as a series of coordinates. e.g. a GPS position or coastline map. May be a point, line, area, etc in either 2D or 3D space. Generally independent of region settings.

;[http://grass.osgeo.org/grass64/manuals/html64_user/vectorintro.html Vector Intro]
[[Vectordata]]

=== Imagery Data ===
Pixelated photographic or satellite images, often imported from a
[http://en.wikipedia.org/wiki/GeoTIFF GeoTIFF] or PNG image file.

As far as the GIS is concerned this is just another raster map, but there are several modules specially tailored for rectification and processing common imagery types. e.g. ortho-photos or multi-channel [[LANDSAT]] data.

* [http://grass.osgeo.org/grass64/manuals/html64_user/imageryintro.html GRASS Imagery module introduction]

* The GRASS [[Image processing]] wiki page

===Site Data===
Old versions of GRASS (5 and earlier) treated point data separate to line and polygon data. GRASS 6 classes all vector data features the same. Convert old sites file data into GRASS 6 vector format with the GRASS 6 [http://grass.osgeo.org/grass64/manuals/html64_user/v.in.sites.html v.in.sites] or
[http://grass.osgeo.org/grass64/manuals/html64_user/v.in.sites.all.html v.in.sites.all] modules.

==Conversions between data types==

The following table is intended to catalog transformations from one type of data to another: 
''[table is currently incomplete!]''

{| border="1"
| From / To
![http://grass.osgeo.org/grass64/manuals/html64_user/rasterintro.html Raster]
![http://grass.osgeo.org/grass64/manuals/html64_user/raster3dintro.html 3D Raster]
![http://grass.osgeo.org/grass64/manuals/html64_user/vectorintro.html Vector]
|-
! Raster
| r.mapcalc
| r.to.rast3
| r.to.vect, v.sample, r.volume
|-
! 3D Raster
| r3.to.rast, r3.cross.rast
| r3.mapcalc
|
|-
! Vector
| v.to.rast, v.surf.rst, v.surf.idw
| v.vol.rst, v.vol.idw, v.to.rast3
| v.clean
|-
! Data
| r.in.*
| r3.in.*
| v.in.*
|}

==How a GRASS project is organized==

GRASS data is stored in a three level structure, the database, location and mapset. These can be found in a series of nested directories on the user's computer. All three must exist and are set at GRASS startup time.

===The Database===

The directory in which all GIS data is to be stored.

e.g. <tt>~/grassdata/</tt>

===The Location===

A ''location'' is a GRASS project consisting of an area, projection definition (or unprojected), a grouping of mapsets, all with the same projection settings. A location is a subdirectory of the GRASS ''database''.

e.g. world_lat_lon, utm_zone_59, or west_coast

A ''location'' contains one or many ''mapsets''.

===The Mapset===

A ''mapset'' contains map(s), it is a subdirectory of a ''location''.
Conceptually, if several mapsets are used in a location, they may be assigned to different users (each has one or several own mapsets to work in and cannot modify thos of other users), and/or it they are used to organize a project (''location'') by subareas or subprojects.
There are no specific organizational limitations.

There is always a PERMANENT mapset which is readable from all other mapsets within the same location. Read access to maps in other mapsets is managed with the 'g.mapsets' command or by adding the "@" symbol and mapset name (e.g. <tt>map@othermapset</tt>).

==Raster GIS Analysis==

===Simple Raster Math===

Sometimes when analyzing the relationship between two or more raster data sets, a relatively simple mathematical approach is best. One example using the {{cmd|r.mapcalc}} tool would be to look at changes between two raster data sets. By subtracting the values in these two data sets you can assume that resulting cells with a positive value have a positive change and those with a negative value have negative change. If the cell values have a zero value then there would be no change.

GRASS comes bundled with the {{cmd|r.mapcalc}} command line tool as well as a GUI interface for the tool accessible using the {{cmd|r.mapcalculator}} command. This GUI allows the user to easily assign raster maps to the variables used in the formulas and easily create mathematical strings that will result in a new raster data set containing the results.

[[Category:Development]]
[[Category:Community]]

Large File Support

2007-04-14T15:03:23Z

⚠️FrancescoLovergine:

(largely based on comments by Glynn Clements on the GRASS-dev mailing list)

== The need ==

Standard C <stdio.h> file functions return file sizes as long integer. On 32-bit systems this overflows at 2 gigabytes. For support of files bigger than this, you need LFS. Currently only implimented in GRASS in libgis. (i.e. there is support for reading+writing raster maps, but not many import/export modules or vector functions have it)

== The issues ==

The problem is that ftell() returns the result as a (signed) long. If
the result won't fit into a long, it returns -1 (and sets errno to
EOVERFLOW).

This can only happen if you also set _FILE_OFFSET_BITS to 64 so that
fopen() is redirected to fopen64(), otherwise fopen() will simply
refuse to open files larger than 2GiB (apparently, this isn't true on
some versions of MacOSX, which open the file anyhow then fail on
fseek/ftell once you've passed the 2GiB mark).

If you want to obtain the current offset for a file whose size exceeds
the range of a signed long, you instead have to use the (non-ANSI)
ftello() function, which returns the offset as an off_t.

'''''TODO:''''' But before we do that, we would need to add configure checks so that we don't try to use ftello() on systems which don't provide it.

There isn't a truly portable solution. Some platforms might not even
have an integral type larger than 32 bits.

The most practicaly solution is to use ftello() if it's available.

This will require some configure checks. These are simple enough to
implement; it's the design which is problematic (as usual).

Unlike most HAVE_FOO checks, fseeko() isn't a simple have/don't-have
check. Rather, it's usually a case that the function is available only
when certain macros are defined (e.g. _LARGEFILE_SOURCE).

That gives rise to the question of what we check for, how we check for
it, how we pass that information to the code, and how we use it.

The trick is deciding what to test, and what to indicate. Do we want
to know:

1. Whether ftello() exists with the default CFLAGS/CPPFLAGS?

2. Whether ftello() exists with the default CFLAGS/CPPFLAGS plus a
fixed selection of additional switches (e.g. -D_LARGEFILE_SOURCE)?

3. Whether ftello() exists with the default CFLAGS/CPPFLAGS plus a
variable selection of additional switches (e.g. -D_LARGEFILE_SOURCE)
with those switches being communicated via an additional variable?

The test would need to be:
#if defined(HAVE_FTELLO) && defined(HAVE_FSEEKO)
as you are using both of those.

Also, if the existence of FSEEKO/FTELLO is conditional upon certain
macros (e.g. _LARGEFILE_SOURCE), you have to ensure that those macros
are defined before the first inclusion of <stdio.h>, including any
"hidden" inclusion from other headers, which essentially means that
you have to ensure that the macros are defined before you include any
other headers (except for <grass/config.h>).

Rather than try to come up with some infrastructure which allows us to
use LFS in a piecemeal fashion, it would be preferable to clean up the
GRASS code so that we can enable LFS globally. Then, we can just add:

-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64

to CPPFLAGS, and not have to worry about adding the necessary macros
to individual files. Any HAVE_* checks then become simple
have/don't-have checks.

My inclination would be to add:

extern off_t G_ftell(FILE *fp);
extern int G_fseek(FILE *stream, off_t offset, int whence);

These would be implemented using fseeko/ftello where available, and
fseek/ftell otherwise. That eliminates the need to perform checks in
individual source files. However, we would need to take care not to
use them in code which can't handle large offsets (i.e. code which
will truncate off_t values to int/long).

If you use -D_FILE_OFFSET_BITS=64, fopen() should be redirected to
fopen64(). There are reports that the MacOSX fopen() is equivalent to
fopen64() even without additional switches.

== Coding LFS in GRASS ==

Currently the <tt>--enable-largefile</tt> switch only enables LFS in libgis, not anywhere else.

[Although config.h includes definitions to enable LFS automatically,
those definitions are currently inactive. This is probably a good
thing; a lot of GRASS' code isn't LFS-aware, and explicit failure is
preferable to silently corrupting data.]

To enable LFS elsewhere, you need to manually add
-D_FILE_OFFSET_BITS=64 to the compilation flags. The simplest approach
is to add to the module's Makefile:

ifneq ($(USE_LARGEFILES),)
EXTRA_CFLAGS = -D_FILE_OFFSET_BITS=64
endif

and add include <tt>config.h</tt> before '''all''' other header files in the code.
#include <grass/config.h>
#include <stdio.h>
#include <string.h>
#include <grass/gis.h>
...

=== int versus off_t ===
You may as well just use "<tt>off_t filesize</tt>" unconditionally. An
"off_t" will always be large enough to hold a "long".

If using "<tt>off_t</tt>", be sure to add:
#include <sys/types.h>

== Issues related to import/export of maps ==

Some exporting/inporting formats have their own intrinsic limitations, see for instance
http://www.gdal.org/formats_list.html

== LFS-safe libs and module list ==
* libgis

* r.in.arc
* r.in.ascii
* r.out.arc
* r.out.ascii
* r.proj.seg
* r.terraflow

== LFS works in progress ==

* r.in.xyz
* r.terraflow (intregrate current LFS support into GRASS's --enable-largefile ./configure switch) (r.terraflow creates huge temporary files which can easily go over 2GB)

== LFS wish list ==
'''High priority modules to get LFS'''
* r.in.*
* r.out.*
* GRASS GDAL plugin (??)
* v.surf.rst
* v.surf.idw(2)
* vector libs (limited by number of features)
* v.in.ascii -bt (without topology)
* DB libs

== References ==

* [http://www.suse.de/~aj/linux_lfs.html LFS support in Linux]
* [http://opengroup.org/platform/lfs.html Adding Large File Support to the Single UNIX® Specification]
* [http://www.sun.com/software/whitepapers/wp-largefiles/largefiles.pdf Large Files in Solaris: A White Paper]

[[Category: Development]]

GRASS in Debian

2007-04-07T08:08:54Z

⚠️FrancescoLovergine:

Grass in Debian is maintained by the [http://pkg-grass.alioth.debian.org/cgi-bin/wiki.pl DebianGis] Team. Some modifications to the code base are due to the [http://www.debian.org/doc/debian-policy/ Debian Policy] compliancy required by the distribution. You can find that the Debian stable version is generally older that the current stable version of Grass: that is due to the releasing and maintainance roadmap of Debian.

Unofficial newer packages for Debian stable can be available by third parties and/or in the [http://pkg-grass.alioth.debian.org/cgi-bin/wiki.pl/DebianGisRepository DebianGis repository]. Generally you can mix those packages with [http://www.backports.org/ backports.org] packages in order to work on a more up-to-date workstation, but the result can be less stable and coherent than the official release, because they are generally built using unstable snapshots.

GRASS in Debian

2007-04-07T08:07:06Z

⚠️FrancescoLovergine: Introducing Grass in DebianGis

Grass in Debian is maintained by the [http://pkg-grass.alioth.debian.org/cgi-bin/wiki.pl DebianGis] Team. Some modifications to the code base are due to the Debian Policy compliancy required by the distribution. You can find that the Debian stable version is generally older that the current stable version of Grass: that is due to the releasing and maintainance roadmap of Debian.

Unofficial newer packages for Debian stable can be available by third parties and/or in the [http://pkg-grass.alioth.debian.org/cgi-bin/wiki.pl/DebianGisRepository DebianGis repository]. Generally you can mix those packages with backports.org packages in order to work on a more up-to-date workstation, but the result can be less stable and coherent than the official release, because they are generally built using unstable snapshots.

AddOns

2007-03-23T17:00:58Z

⚠️FrancescoLovergine: Fixed jachym urls

This page contains references to user contributions and add-ons (the original GRASS GIS software can be downloaded [http://grass.itc.it/download/index.php here]).

__TOC__

==Copyright and licensing information==

''Please be sure to include copyright and licensing information in the header comments of your code so that others may know how they can use, extend, modify, and redistribute your work.''

e.g. at the top of a shell script:
<pre>
#!/bin/sh
############################################################################
#
# MODULE: v.in.e00
#
# AUTHOR(S): Markus Neteler, Otto Dassau
#
# PURPOSE: Import E00 data into a GRASS vector map
# Imports single and split E00 files (.e00, .e01, .e02 ...)
#
# COPYRIGHT: (c) 2004, 2005 GDF Hannover bR, http://www.gdf-hannover.de
#
# This program is free software under the GNU General Public
# License (>=v2). Read the file COPYING that comes with GRASS
# for details.
#
#############################################################################
#
# REQUIREMENTS:
# - avcimport: http://avce00.maptools.org

[script follows]
</pre>

==Shell script coding standards==

Please have a look at our [http://grass.itc.it/grass63/source/SUBMITTING_SCRIPTS Shell script coding standards] before submitting here.

==Miscellaneous Add-ons==

* [http://bambi.otago.ac.nz/hamish/grass/utm_which_zone.sh utm_which_zone.sh] is a shell script to determine UTM zone from Lat/Lon input. Requires [http://www.octave.org Octave] to be installed. A shell-only version is [http://dcalvelo.free.fr/grass/utm_which_zone_sh.sh available] which only requires awk. '''Authors''': Hamish Bowman (Octave part), Markus Neteler (shell script wrapper), Daniel Calvelo (sh+awk version)

* Perl scripts for converting data forth and back between Excel files and PostgreSQL: [http://dcalvelo.free.fr/grass/pg2xls.pl pg2xls.pl] reads data from PostgreSQL and produces an excel workbook; [http://dcalvelo.free.fr/grass/xls2sql.pl xls2sql.pl] reads excel files and outputs SQL statements to be fed into an RDBMS. Both scripts need modules from [http://www.cpan.org CPAN], especially [http://search.cpan.org/dist/Spreadsheet-ParseExcel/ Spreadsheet::ParseExcel] for xls2sql.pl and [http://search.cpan.org/~tmtm/Spreadsheet-WriteExcel-FromDB Spreadsheet::WriteExcel::FromDB] and its dependencies for pg2sql.pl. Check the source headers for more info. '''Authors:''' Daniel Calvelo (xls2sql.pl), Markus Neteler (pg2xls.pl)

* [http://dream.lrrl.arch.tu-muenchen.de/~wqual/perl/dbf2sql.tgz dbf2sql] is a Perl script for translating dbf-tables into a sql-command. dbf-tables are read using dbfdump-command from dbd-xbase-perl module ([http://search.cpan.org/~janpaz/DBD-XBase-0.241/ dbd::xbase] and [http://search.cpan.org/~jv/Getopt-Long-2.35/lib/Getopt/Long.pm getopt::long] have to be installed from CPAN first). There are problems, if the last column of the table contains characters. Suggestions for improvements welcome! '''Author:'''Wolfgang Qual

* [http://www.igc.usp.br/pessoais/guano/downloads/azimuth2.c azimuth2.c] is a small C program to calculate the azimuth and length of vector lines exported by GRASS-GIS as ASCII files (like this: v.out.ascii input=vector output=ascii format=standard). It is useful for create rose diagrams of lineament maps. Improvements on the original code after suggestions by Örs Téglásy, Hungary. '''Author:''' Carlos Henrique Grohmann

==GRASS 5.x==

===Vector add-ons for GRASS 5===

* See here: http://grass.itc.it/download/addons.php

===Raster add-ons for GRASS 5===

* See here: http://grass.itc.it/download/addons.php

* [http://www.valledemexico.ambitiouslemon.com/gwmodelling.html r.gmtg] The groundwater modelling tool for grass. A module to use MODFLOW within GRASS. '''Author''': Jaime Carrera

==GRASS 6.x==

===Vector add-ons===

* [http://geni.ath.cx/grass/v.out.gmt v.out.gmt] is a shell script that exports a polygon vector file into GMT xy file. psbasemap code was copied from Hamish's r.out.gmt. '''Author:''' Huidae Cho, Hamish Bowman, Dylan Beaudette

* [http://www.pois.org/florian/downloads/grass/v.strahler.tgz v.strahler] is a module that calculates the Strahler Order for all lines of a given dendritic network. '''Author:''' Florian Kindl. Available via SVN: svn co https://grasssvn.itc.it/svn/grassaddons/trunk/grassaddons/v.strahler

* [http://svg.cc/grass/index.html v.out.svg] is a module that exports SVG notation along with optional attribute data directly from GRASS 6.x vector layers. Now part of grass63-cvs. '''Author:''' Klaus Förster

* [http://les-ejk.cz/programs/ v.trees3d] is a module for making 3D trees from input vector point file. '''Author:''' Jachym Cepicky

* [http://www.public.asu.edu/~cmbarton/files/grass_scripts/v.lda v.lda] is a shell script for calculating Ian Johnson's (U. Sidney) Local Density Analysis values to measure clustering of point data at different neighborhood radii. There is an option to create a simple line graph of the results. There have been reports of problems creating the line graph on Cygwin installations of GRASS. '''Author:''' Michael Barton

* [http://www.public.asu.edu/~cmbarton/files/grass_scripts/v.append v.append] is a shell script combining two vector files AND their associated attribute tables. The vector files should be of the same type and, for best results, should have identically formatted attribute tables. '''Author:''' Michael Barton

* [http://www.shockfamily.net/cedric/grass/v.group v.group] generates a new vector map with the same geometry as an existing map. The new map has categories and a table based on grouping by the values in certain columns of the existing map's table. The values in these columns are preserved in the table for the new map. It's like a v.reclass that preserves data. '''Author:''' Cedric Shock

* [http://bambi.otago.ac.nz/hamish/grass/v.out.ascii.db v.out.ascii.db] is a shell script for exporting vector point data coordinates and selected attribute columns to either a file or to the console. '''Author:''' Hamish Bowman

* [http://les-ejk.cz/programs v.rasterbounds] is a shell script for creating polygon-vector file of rasterfile boundaries. The best version of GRASS is 6.1+. If you are using GRASS < 6.1, you have to be in the same mapset as your raster maps are from. '''Author:''' Jachym Cepicky

* [http://www.clubwebcanada.ca/twiens/v.sample.buffer.tgz v.sample.buffer] is a shell script that samples rasters in buffers of a specified size around features in a specified vector file. Sampling results are added as attributes to the vector file. This script was designed for sampling vegetation indices and DEM derived attributes for bird point counts. Sampling results can be one or more basic statistics such as mean, range, max, etc. '''Author:''' Trevor Wiens

* [http://www.gfosservices.it/materiale_didattico/moduli/grass_kriging.tar.gz v.variogram] is a script that create an omnidirectional experimental semi-variogram. This scripts require R-statistics software installed on your machine. Now the script is updated to run on spgrass6 >= 0.3 and sp >= 0.9 [http://grass.itc.it/pipermail/statsgrass/2006-October/000455.html reply]. '''Author:''' Ivan Marchesini, Pierluigi De Rosa.

* [http://www.gfosservices.it/materiale_didattico/moduli/grass_kriging.tar.gz v.surf.krige] is a script that do a surface interpolation from vector point data by Kriging method. The interpolated value of a cell is determined by using an omnidirectional variogram model fitted starting from model parameter given by user shown from the experimental semi variogram produced by v.variogram. The script can perform also the Leave-One-out cross validation to test the variogram model "fitted by eye" and an automatic fitted variogram model. The cross validation helps the user to choose the best variogram model to interpolate own data. '''Author:''' Pierluigi De Rosa.

* [http://ngeo.de/grassstuff/v.lmeasure v.lmeasure] and [http://ngeo.de/grassstuff/v.revlmeasure v.revlmeasure] are two perl scripts that place equidistant vector points along a given arbitrary vector line starting from the beginning or end of the vector line, respectively. Resulting vector points are labeled with the distance from origin. '''Author:''' Mats Schuh

* [http://david.p.finlayson.googlepages.com/v.swathwidth v.swathwidth] creates a vector map representing the sea bottom coverage of a multibeam (swath) sonar survey. '''Author:''' David Finlayson

* [http://kufaya.googlepages.com/v.flip.zip v.flip] flips the direction of selected vector lines. '''Author:''' Maciej Sieczka

* [http://phygeo7.geo.uni-augsburg.de/gis2/scripts/v.digatt v.digatt] (shell script) Interactively assign numeric table attributes to series of vector objects. It is meant to be effective by avoiding to type in the attribute value for all single objects again and again. The user is prompted for typing in an attribute value which is assigned to all objects selected by mouseclick afterwards. Next the display is redrawn after updating the table column. Zooming allows to change the region before the old value can be reused or a new one can be typed in (or copied by mouse from another object) in order to assign it to the next series of objects etc. It is tested not very extensively yet. Therefore better work with a copy of your map and consider using v.digit or d.what.vect -e alternatively. [http://phygeo7.geo.uni-augsburg.de/gis2/scripts/v.digatt.png screenshot]. '''Author:''' Andreas Philipp

* [http://k153-85.fsv.cvut.cz/cgi-bin/viewcvs.cgi/grass6/vector/v.in.gama/ v.in.gama] converts [http://www.gnu.org/software/gama/ GNU GaMa] XML output file to a GRASS vector map layer. '''Author:''' Martin Landa

* [http://kufaya.googlepages.com/v.breach.zip v.breach] creates vector maps of lines and points of continously lowering elevation down the input watercourses, based on the input raster DEM. '''Author:''' Maciej Sieczka

* [http://kufaya.googlepages.com/v.line.center.zip v.line.center] creates a points vector map with each point located in the middle of the length of one input vector line. '''Author:''' Maciej Sieczka

===Raster add-ons===

* [http://www.igc.usp.br/pessoais/guano/downloads/r.roughness r.roughness] is a shell script to calculate the surface roughness of a DEM, using r.surf.area and v.surf.rst. (for GRASS versions 6.1 and above)
* [http://www.igc.usp.br/pessoais/guano/downloads/r.roughness60 r.roughness60] - for GRASS versions 6.0.X '''Author:''' Carlos Henrique Grohmann

* [http://www.les-ejk.cz/files/programs/grass/r.gauss.tgz r.gauss] is Gaussian and Laplacian of Gaussian filter for GRASS. It is written in C language. '''Author:''' Jachym Cepicky

* [http://les-ejk.cz/files/programs/grass/r.mlv.tgz r.mlv] is Mean of least variance filter for GRASS. It is an edge-preserving (or even edge-enhacing) filter, which should serve for removing additive noise from images. It is written in C language. '''Author:''' Jachym Cepicky

* [http://les-ejk.cz/files/programs/grass/r.bilateral.tgz r.bilateral] Bilateral filter is an edge-preserving filter, which combines domain and range filtering. It is written in C language. '''Author:''' Jachym Cepicky

* [http://les-ejk.cz/files/programs/zc.pl Zero crossing] is a simple Perl script, finds the ,,zero crossings`` from the Laplacian of Gaussian filter (see above). It is really very simple, the edges don't need to be really on that pixel, where they are detected, no interpolation is performed. '''Author:''' Jachym Cepicky

'''Usage:'''
zc.pl -i input -o output |r.mapcalc

* [http://les-ejk.cz/files/programs/local_max.pl Local maxima] is a Perl script for <code>r.mapcalc</code>. It detects local maxima of the image. '''Author:''' Jachym Cepicky

'''Usage:'''
local_maxima.pl -i input -o output -s matrix_size|r.mapcalc

* [http://bambi.otago.ac.nz/hamish/grass/r.out.gmt r.out.gmt] is a GRASS script for exporting a GRASS raster map into a [[http://www.soest.hawaii.edu/gmt/ GMT]] grid file. It also creates a GMT color table from the data and can generate some GMT commands for plotting a postscript file. (code is experimental, but functional) see also http://169.237.35.250/~dylan/grass_user_group/#GMT_and_GRASS-overview '''Authors:''' Hamish Bowman, Dylan Beaudette

* [http://geni.ath.cx/grass/r.out.gmt yet another r.out.gmt] is a modified version of Hamish's r.out.gmt. Added options for title, xlabel, ylabel, comment, and map width. Removed any settings that can be changed by gmtset for more flexibility. '''Author:''' Hamish Bowman, Huidae Cho, Dylan Beaudette

* [http://bambi.otago.ac.nz/hamish/grass/r.pack r.pack] and [http://bambi.otago.ac.nz/hamish/grass/r.unpack r.unpack] are two GRASS scripts for transfering raster maps to another computer as a single file. '''Author:''' Hamish Bowman

* [http://bambi.otago.ac.nz/hamish/grass/dominant_dir.m dominant_dir.m] and [http://bambi.otago.ac.nz/hamish/grass/calc_terraflow_dir.m calc_terraflow_dir.m] are two Matlab scripts for determining the dominant flow direction from a r.terraflow MFD map and converting into a GRASS aspect map for use with d.rast.arrow, etc. '''Author:''' Hamish Bowman

* [http://www-pool.math.tu-berlin.de/~soeren/grass/modules/ r.in.onearth] for download and import satellite images direct from the NASA onearth WMS server into GRASS. '''Author:''' Soeren Gebbert

* [http://les-ejk.cz/files/programs/grass/r.in.wms.tgz r.in.wms] for download and import maps direct from WMS servers into GRASS. This script is written in Python Programming language. '''Author:''' Jachym Cepicky

* [http://www.shockfamily.net/cedric/grass/r.tileset r.tileset] generates a list of tiles and sizes in a source projection that cover the region in the current database with appropriate resolution. The size of individual tiles can be constrained. Only tiles intersecting the current region are returned. These tilings are appropriate for requesting data from another projection to meet the specifications of the current region. For example, it could be used to generate tile requests to a latitude / longitude WMS server like this <code>r.tileset -w sourceproj="+init=epsg:4326"</code>. '''Author:''' Cedric Shock

* [ftp://gsca.nrcan.gc.ca/outgoing/Patton/Grass/Scripts/r.csr.tar.bz2 r.csr] integrates several Grass programs to produce colored, shaded-relief rasters in one step. Accepts single or multiple elevation/bathymetry maps as input; optionally will fill data holidays with 3x3 median filter, multiple times, if required; can apply color maps from a) input raster, b) another raster in MAPSET, or c) from a rules file; otherwise, rainbow colorbar is applied. Output colored, shaded-relief rasters can optionally be exported to tiff format and archived using tar with gzip/bzip2 compression if appropriate flags are given. Shading parameters can be modified, though useful defaults are given. '''Author:''' Eric Patton

* [ftp://gsca.nrcan.gc.ca/outgoing/Patton/Grass/Scripts/r.fragment.tar.bz2 r.fragment] fragments a raster into a user-defined set of smaller tiles according to an input number of rows and columns. Optionally, a null value threshold can be set to filter out candidate tiles that would have a large percentage of null cells. '''Author:''' Eric Patton

* [http://david.p.finlayson.googlepages.com/r.eucdist r.eucdist] creates a raster map estimating the euclidean distance from known cells. '''Author:''' David Finlayson

* [http://david.p.finlayson.googlepages.com/r.smoothpatch r.smoothpatch] creates a composite of two rasters using a distance-weighted average across the transition to smooth the edges. '''Author:''' David Finlayson

* [http://www.faunalia.it/download/r_li/ r.li] is a more flexible and faster replacement of the old r.le. '''''Moved into 6.3-CVS'''''. '''Authors:''' Claudio Porta, Davide Spano, Serena Pallecchi, [http://www.faunalia.it Faunalia]

* [http://kufaya.googlepages.com/r.surf.nnbathy.zip r.surf.nnbathy] interpolates a surface from a raster input using the [http://www.marine.csiro.au/~sakov/ nn] natural neighbor interpolation library. Provides triangulation, Sibson natural neighbor interpolation and non-Sibsonian interpolation. '''Author:''' Maciej Sieczka

* The GRASS Image Processing Environment (GIPE) has USLE, Energy-balance and radiance-reflectance correction models. '''Author:''' Yann Chemin (unless specified otherwise). It is available by anonymous reading through this command (thanks Markus!): 
svn co https://grasssvn.itc.it/svn/grassaddons/trunk/grassaddons grassaddons/gipe
 
- r.usler creates USLE R factor (Rainfall erosivity) from annual precipitations.
It has 4 methods, Morgan, Roose, Foster and El-Swaify to choose from.
'''Authors:''' Natalia Medvedeva and Yann Chemin 
- r.uslek creates USLE K factor (soil erodibility) from sand, clay, silt fractions
and organic matter fraction. Based on USDA 1951 (p209) quoted in FAO World Soil CD,
and from some generic [soil class+OM] to K conversion table. 
- r.albedo creates Albedo. Albedo is the shortwave surface reflectance in the range
of 0.3-3 micro-meters. This module takes Modis, Aster, Landsat or AVHRR individual
surface reflectance bands to calculate Albedo. This module is a precursor to r.sun
or any Energy-Balance related processing. 
- r.eb.* are a set of 10+ GRASS modules that together perform the main functions of
the SEBAL model (Bastiaanssen, 1995). Those functions include (but are not limited to)
Soil heat flux, sensible heat flux, net radiation, evaporative fraction at satellite
overpass, diurnal actual evapotranspiration, momentum roughness length, etc. These
modules are also part of any Energy-Balance related processing. 
- r.evapo.potrad creates diurnal Potential evapotranspiration assuming all net radiation
becomes ET, according to SEBAL model (Bastiaanssen, 1995). This module also has a flag for
diurnal net radiation as required by SEBAL in r.eb.eta. 
- r.vi creates a given Vegetation index from a list of 13 of them, most of them only
requiring Red and NIR. Updated to accept all types of input data.
'''Authors:''' Baburao Kamble and Yann Chemin 
- r.vi.mpi is the mpi verion for cluster GRASS GIS education (no speed up here!).
'''Author:''' Shamim Akhter 
- r.dn2ref.l7, r.dn2ref.ast create top of atmosphere reflectance for Landsat 7ETM+ and
ASTER. These modules also have a flag for radiance output. Updated r.dn2ref.l7 to read .met
calibration file. 
- r.dn2full.l7 is an attempt to get all bands of Landsat7 calibrated and corrected to
either reflectance or temperature, reads only the .met file. 
- r.dn2potrad.l7] is an attempt to get ET potential from DN of Landsat 7 (Careful! No
Atmospheric correction!). 
- r.biomass creates biomass growth map from fPAR, lightuse efficiency, water availability
(or evap.fraction), Lat, doy and tsw.

* r.boxcount and r.boxcount.sh calculate the fractal dimension for a given map. These are versions for grass6 of [http://www.ucl.ac.uk/~tcrnmar/ Mark Lake's modules] for grass43. '''Authors:''' Mark Lake, grass6 port: Florian Kindl. Available via SVN: svn co https://grasssvn.itc.it/svn/grassaddons/trunk/grassaddons

===General add-ons===

* [http://www.nature-consult.de/dassau/g.laptop/g.laptop.sh g.laptop.sh] is an interactive shell script to extract raster and vector data from current Location into a new one. Data can be copied or extracted in current or original resolution and region extend. This script was written to extract smaller parts of a GRASS location to be able to present them on a laptop without the necessity to transfer huge data. Maps do not have to be in the same mapset. '''Author:''' Otto Dassau

* '''''Readline completion''''' for GRASS commands under the bash shell: [http://www.sorokine.info/grass-complete/ grass-complete] won't clutter the environment but needs to be installed; [http://dcalvelo.free.fr/grass/grass_rlcompleter.sh grass_rlcompleter.sh] needs almost no installation but will pollute the environment. Grass-Complete currently requires Bash version 2.05 for proper install. '''Author:''' Alexandre Sorokine (grass-complete), Daniel Calvelo (grass_rlcompleter.sh)
 

=== Imagery add-ons ===

* i.atcorr: Atmospheric Correction using Christo Zietsman's implementation of 6s code in C/C++. Available in SVN: 
svn co https://grasssvn.itc.it/svn/grassaddons/trunk/grassaddons grassaddons/gipe
 '''Author:''' Christo Zietsman

* [http://bambi.otago.ac.nz/hamish/grass/gdal/i.warp61 i.warp61] is a shell script that will use gdalwarp to rectify a raw input image using thin plate splines. The map should be imported into GRASS with r.in.gdal and GCPs set with i.points. Input is the raw image (GeoTIFF, JPEG, etc). Output is a GeoTIFF in the imagery group's target location's map projection. Requires a recent (early 2006) version of GRASS 6.1, or newer. '''Author:''' Hamish Bowman
 

=== Display add-ons ===

==== [[IconSymbols]] ====
* [[IconSymbols|Symbols]] which can be used with ''d.vect, d.graph'', and ''ps.map''.

==== Modules ====

* [http://bambi.otago.ac.nz/hamish/grass/d.frame.quarter d.frame.quarter] is a shell script that will split the display into four quadrants using ''d.frame''. Individual frames are named ''uno, dos, tres, cuatro'', and ''full_screen''. '''Author:''' Hamish Bowman

* [ftp://gsca.nrcan.gc.ca/outgoing/Patton/Grass/Scripts/d.hyperlink.tar.bz2 d.hyperlink] is an interactive shell script that allows the viewing of hyperlinked images from a vector's attribute table in an external image viewer. Queries can be made via SQL statements or interactive mouse-clicking. The attribute table must be pre-populated with a column containing the image to link the vector to; the user also specifies the image folder in the current MAPSET where the images are located. The script currently supports gimp, Eye of Gnome, gthumb, gpdf, and Inkscape image viewers. '''Author: '''Eric Patton

* [http://www.ornl.gov/sci/gist/software/grass/ pd-GRASS]: Parallel Display for GRASS GIS '''Author:''' Alex Sorokine

* [http://bambi.otago.ac.nz/hamish/grass/d.region.box d.region.box] is a shell script that quickly displays a box around the current region. '''Author:''' Hamish Bowman

* [http://bambi.otago.ac.nz/hamish/grass/d.stations d.stations] is a shell script that quickly displays vector points (or sites for GRASS 5.4 and below). '''Author:''' Hamish Bowman

* [http://bambi.otago.ac.nz/hamish/grass/d.varea d.varea] is a shell script that quickly displays vector areas. '''Author:''' Hamish Bowman

===Postscript add-ons===

* [http://les-ejk.cz/programs/grass/ps.atlas ps.atlas] is a shell script that makes more maps on current region according to input *.psmap file. General map can be stored as vector file. The resulting *.eps maps can be automatically converted to *.pdf files. '''Author:''' Jachym Cepicky

* [[ps.map scripts|ps.map samples/templates]]

==== [[AreaFillPatterns]] ====
* Hatches for ps.map's vareas

===GRASS and UMN Mapserver===

* [http://www.mail-archive.com/mapserver-users@lists.umn.edu/msg00086.html See interesting posting]

[[Category:Community]]
[[Category:Development]]
[[Category:Documentation]]
[[Category:Installation]]

How to participate in IRC communication

2006-08-01T10:10:47Z

⚠️FrancescoLovergine: /* Background */

==Background==

Internet Relay Chat (IRC) is an online system of communication. It is a form of instant communication over the Internet. It is mainly designed for group (many-to-many) communication in discussion forums called channels, but also allows one-to-one communication. The basic means of communication in an established IRC session is a channel. Users can join to channels (using the command /join #channelname) and then send messages to it, which are then relayed to all other users in the same channel. Users access IRC networks by connecting a client to a server. There are many client and server implementations. Most IRC servers do not require users to log in, but a user will have to set a nickname before being connected.

The GRASS community uses the dedicated channel ([irc://irc.freenode.net/grass #grass] on irc.freenode.net), feel free to join. There are many other geo related channels such as [irc://irc.freenode.net/gdal #gdal], [irc://irc.freenode.net/qgis #qgis], [irc://irc.freenode.net/mapserver #mapserver], [irc://irc.freenode.net/osgeo #osgeo], [irc://irc.freenode.net/proj #proj], [irc://irc.freenode.net/foss4g2006 #foss4g2006] etc.

People interested in being involved in the [http://pkg-grass.alioth.debian.org/ Debian Gis project] can join a dedicated channel ([irc://irc.oftc.net/debian-gis #debian-gis] on irc.oftc.net). A
[irc://irc.oftc.net/geo #geo] channel is also available on the same network.

==How to do it the first time==

#Get a IRC client software (see [http://en.wikipedia.org/wiki/List_of_IRC_clients software list]). We like the [https://addons.mozilla.org/extensions/moreinfo.php?id=16 Chatzilla extension for Firefox], [http://gaim.sourceforge.net/ gaim], [http://xchat.org/ xchat] and on MacOSX the [http://colloquy.info/ Colloquy] software.
#Connect to IRC, for "our" channels to a freenode.net server ([http://freenode.net/irc_servers.shtml list of servers]).
#Define some settings: Here some useful commands which you will enter into the field to also enter the communication (be aware to not start such commands with a space!). Anything started with /command will not be visible to the others:

<pre>
# select nick name
/nick yournickname

## better don't show your email address:
/ns set hide email on

### register (only one time needed) - PW is in clear text!!
/msg NickServ register [password] [email]

### identify yourself to the IRC server (always needed) (xxxx == pw)
/msg NickServ IDENTIFY xxxx
</pre>

====Join a channel====

<pre>
/join #grass
</pre>

Now you will see (depends on your client) the list of people lurking in the channel. You may convey your greetings and go ahead for conversation...
See below how to automate the identification process.

http://grass.itc.it/images/irc_chatzilla.png



The communication is logged (see [http://logs.qgis.org/grass/ #grass archives]).

==Some useful hints==

With chatzilla and other clients you can set your nickname in the preferences. You can also open several channels at time. It's convenient to automate the identification.

===Chatzilla auto-identification===

You can put the next command as "autoscript" into chatzilla's settings
for each channel, see Edit -> Preferences -> Global Settings -> Startup tab
-> Auto-url [someone please verify this, probably it's sufficient to type
below one time into chatzilla]:
<pre>
# auto-identify yourself to the IRC server (xxxx == pw)
/network-pref autoperform msg nickserv identify xxxx
</pre>

To quickly open the GRASS channel in Chatzilla, simply click here:
irc://freenode/grass

Try to find the [http://freenode.net/irc_servers.shtml next freenode server] to have speedy connection (e.g., Italy: irc://calvino.freenode.net/grass).

===TAB extension===

A nice feature is to use TAB key for type completion of nick names
in the channel - just try it!

===IRC Ghosts===

If your communication crashed, it can happen that your nick is still online, a so-called "ghost". When you login again, an underscore will be added to your nick name. To takeover your own nick name, you have to kill the "ghost" by entering next command with your password (takes some seconds):

<pre>
# kill ghost after crash (xxxx == pw)
/msg NickServ ghost yournickname xxxx
</pre>

The nick server will then remove the "ghost" and give you your nick name back.

==Further reading==

* [http://en.wikipedia.org/wiki/Internet_Relay_Chat Wikipedia article]
* [http://freenode.net/faq.shtml#contents-userregistration FAQ freenode on user registration and more]

[[Category:Community]]