Geografic-Information-System/lib/init/helptext.html

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<p>
When <a href="grass.html">launching</a> GRASS GIS for the first time, you will open a
<b>default Location</b> "world_latlog_wgs84" where you can find a map layer
called "country_boundaries" showing a world map in the WGS84 coordinate system.
</p>

<center>
  <img src="grass_start.png" alt="[GRASS GIS after first startup]">
</center>

<br>
<p>
The main component of the Data tab is the <em>Data Catalog</em>
which shows the GRASS GIS hierarchical structure consisting of
Database <img src="grassdb.png" alt="[GRASS Database]">,
Location <img src="location.png" alt="[Location]"> and
Mapset <img src="mapset.png" alt="[Mapset]">.
</p>
<dl>
  <dt><img src="grassdb.png" alt="[GRASS Database]">&nbsp;<b>GRASS Database</b> (directory with projects)</dt>
  <dd>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).</dd>
  <dt><img src="location.png" alt="[Location]">&nbsp;<b>Location</b> (a project)</dt>
  <dd>A Location is defined by its coordinate reference system (CRS).
    In the case of the default Location, it is a geographic coordinate reference system
    WGS84 (EPSG:4326). If you have data in another CRS than WGS84, you should create
    a new Location corresponding to your system.</dd>
  <dt><img src="mapset.png" alt="[Mapset]">&nbsp;<b>Mapset</b> (a subproject)</dt>
  <dd>Each Location can have many Mapsets for managing different aspects of
    a project or project's subregions. When creating a new Location, GRASS GIS
    automatically creates a special Mapset called PERMANENT where the core
    data for the project can be stored.</dd>
</dl>

<p>
For more info about data hierarchy, see
<a href="grass_database.html">GRASS GIS Database</a> page.
</p>


<h2>GRASS started in the default Location, now what?</h2>
<p>
First, if you would like to get to know GRASS better before importing your own data,
please download provided samples such as the &quot;North Carolina&quot; dataset.
You can simply reach them through
&quot;Download sample location to current database&quot; management icon
<img src="location-download.png" alt="[Download Location]">.
</p>

<p>
To work with your own data, you typically want to first create a new Location
with a <a href="https://en.wikipedia.org/wiki/Spatial_reference_system">
coordinate reference system (CRS)</a> suitable for your study area or one that
matches your data's CRS. The Location Wizard <img src="location-add.png" alt="[Add Location]">
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.

<h3>Creating a New Location with the Location Wizard</h3>
<p>
If you know the CRS of your data or study area,
you can fill <a href="https://epsg.io">EPSG code</a>
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).
</p>

<h3>Importing data</h3>
After creating a new Location, you are ready to import your data. You can use
simple raster or vector data import <img src="raster-import.png" alt="[Raster import]">,
<img src="vector-import.png" alt="[Vector import]"> or a variety of more specialized tools.
If the data's CRS does not match your Location'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.


<h2>Text-based startup and Location creation</h2>

GRASS GIS can be run entirely without using the graphical user interface.
See <a href="grass.html">examples</a> of running GRASS GIS from a command line.


<h2>See also</h2>

<em>
 <a href="index.html">GRASS GIS 8 Reference Manual</a>
<br>
 <a href="grass.html">GRASS GIS 8 startup program manual page</a>
 <br>
 <a href="https://grass.osgeo.org/learn/">GRASS GIS tutorials and books</a>
</em>

<p>
 <a href="https://epsg.io/">List of EPSG codes</a> (Database of worldwide coordinate systems)

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