When launching GRASS GIS for the first time, you will open a default Location "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 , Location and Mapset .
For more info about data hierarchy, see GRASS GIS Database page.
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 location to current database" management icon .
To work with your own data, you typically want to first create a new Location with a coordinate reference system (CRS) suitable for your study area or one that matches your data's CRS. The Location 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.
If you know the CRS of your data or study area, you can fill EPSG code or description and Location 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).examples of running GRASS GIS from a command line. GRASS GIS 8 Reference Manual
List of EPSG codes (Database of worldwide coordinate systems)
© 2003-2022 GRASS Development Team, GRASS GIS 8.2.0 Reference Manual