GRASS 5.7 tutorial introduction

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README NOTE: This tutorial is refering to GRASS 5.7. Meanwhile (2005), GRASS 6.0.0 has been published. An updated (but unfortunately still incomplete) version of this tutorial is available here: GRASS Six Tutorial.

The default settings

Default settings for vector geometry:

Per default all GRASS 5.7 vectors are stored in native 5.7 format within the directory $GISDBASE/$LOCATION_NAME/$MAPSET/vector/$MAP/. All map related data such as geometry data, spatial index, DB-connection (dbln file) info etc. are stored in this directory. Geometry can be also read from SHAPE or other files directly (see v.external), read from PostGIS and in future maybe also write support for virtual vector maps will be implemented. See Geometry management below for details.

Default settings for vector attributes

Per default all GRASS 5.7 vector attributes are stored in a DBF table within the directory $GISDBASE/$LOCATION_NAME/$MAPSET/dbf. The default settings for attribute storage can be modified with 'v.database'. If required, a map can be linked to a certain table with 'v.db.connect'. See Attribute management below for details.

Default settings for db.* modules

The db.* set of modules can be used for simple SQL tasks in database tables. Connection must be established with 'db.connect' first. See Attribute management below for details.

Following modules are available at time of this writing

Please refer to the online GRASS 5.7 HTML manual pages.

  • If you start a module just by name, a related GUI window pops up.
  • d.m is the new display manager.
  • QGIS is the promising new GUI for GRASS!

    Tutorial Quick Guide

    The table does not refer to all examples, please also check the individual tables of contents. You can combine the different storage methods for geometry and attributes. Per default "Native format" geometry storage and DBF attribute storage is used.

    Native (default) OGR supported formats (SHAPE, MapInfo, PostGIs etc) DBF (default) mySQL PostgreSQL ODBC
    Geometry 2D/3D vectors, topology, Def. / Ex. 2D/3D vectors, pseudotopology, Def. / Ex.1 / Ex.2 needs PostgreSQL , pseudotopology [1], Def. / Ex. not yet implemented -- -- with PostGIS, see there --
    Attributes reads/writes DBF tables, see there with DBF, see there with PostgreSQL, see there not yet implemented Int, Double, String, DateTime (?), Def. / Ex. Int, Double, String, DateTime (?), Def. Int, Double, String, DateTime (?), Def. / Ex. links to various RDBMS , Def.
    Legend: Def.: Definition, Ex.: Example, --: not applicable
    Remarks: [1] PostGIS support: Geometry primitives (points, lines, boundaries, centroids) are stored in PostGIS and topology is build in GRASS. This is implemented for reading, but not yet for writing. PostGIS data are OGC Simple Features compliant while GRASS uses topology. These models are converted accordingly by OGR.

    © 2003-2004 Markus Neteler
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    Last change: $Date: 2008-04-14 11:35:13 +0000 (Mon, 14 Apr 2008) $