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GRASS GIS Quickstart¶
When launching GRASS GIS for the first time, you will open a
default project "world_latlog_wgs84" where you can find a
map layer called "country_boundaries" showing a world map in the
WGS84 coordinate system.
The main component of the Data tab is the Data Catalog which shows the GRASS GIS hierarchical structure consisting of database , project and mapset .
- GRASS database (directory with projects)
-
Running GRASS GIS for the first time, a folder named "grassdata" is automatically created. Depending on your operating system, you can find it in your $HOME directory (*nix) or My Documents (MS Windows). - project (previously called location)
-
A project is defined by its coordinate reference system (CRS). In the case of the default project, it is a geographic coordinate reference system WGS84 (EPSG:4326). If you have data in another CRS than WGS84, you should create a new project corresponding to your system. - mapset (a subproject)
-
Each project can have many mapsets for managing different aspects of a project or project’s subregions. When creating a new project, GRASS GIS automatically creates a special mapset called PERMANENT where the core data for the project can be stored.
For more info about data hierarchy, see GRASS GIS Database page.
GRASS started in the default project, now what?¶
First, if you would like to get to know GRASS better before importing your own data, please download provided samples such as the "North Carolina" dataset. You can simply reach them through "Download sample project to current database" management icon .
To work with your own data, you typically want to first create a new project with a coordinate reference system (CRS) suitable for your study area or one that matches your data’s CRS. The Project Wizard will help you with that by guiding you through a series of dialogs to browse and select predefined projections (also via EPSG code) or to define individual projections.
Creating a New project with the Project Wizard¶
If you know the CRS of your data or study area, you can fill EPSG code or description and Project Wizard finds appropriate CRS from a predefined list of projections. If you do not know CRS of you data, you can read it from your georeferenced data file (e.g. shapefile or GeoTiff file with the related metadata properly included).
Importing data¶
After creating a new project, you are ready to import your data. You can use simple raster or vector data import , or a variety of more specialized tools. If the data’s CRS does not match your project’s CRS, data will be automatically reprojected. After import your raster or vector data are added as a layer to Map Display. To change layer properties, go to Display tab. To analyze your data, search for a tool in the Modules tab.
Text-based startup and project creation¶
GRASS GIS can be run entirely without using the graphical user interface. See examples of running GRASS GIS from a command line.
See also¶
GRASS GIS Reference Manual
GRASS GIS startup program manual page
GRASS GIS tutorials and books
List of EPSG codes (Database of worldwide coordinate systems)
SOURCE CODE¶
Available at: GRASS GIS Quickstart source code (history)
Accessed: Thursday Aug 01 05:15:36 2024
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© 2003-2024 GRASS Development Team, GRASS GIS 8.4.0 Reference Manual
| GRASS 8.4.0 |