add docs for examples commands (#288)

Author: calexat-123

README.md

@@ -30,7 +30,7 @@
 
 Xarray-Spatial implements common raster analysis functions using Numba and provides an easy-to-install, easy-to-extend codebase for raster analysis.
 
-#### Installation
+### Installation
 ```bash
 # via pip
 pip install xarray-spatial
@@ -39,6 +39,18 @@ pip install xarray-spatial
 conda install -c conda-forge xarray-spatial
 ```
 
+### Dowloading our starter examples and data
+Once you have xarray-spatial installed in your environment, you can use one of the following in your terminal (with the environment active) to download our examples and/or sample data into your local directory. 
+
+```xrspatial examples``` : Download the examples notebooks and the data used.  
+
+```xrspatial copy-examples``` : Download the examples notebooks but not the data. Note: you won't be able to run many of the examples.  
+
+```xrspatial fetch-data``` : Download just the data and not the notebooks.
+
+In all the above, the command will download and store the files into your current directory inside a folder named 'xrspatial-examples'.
+
+
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 |<a href="/examples/"><img width="1604" src="img/0-0.png"></a>                           | <a href="/examples/user_guide/2_Proximity.ipynb"><img width="1604" src="img/0-1.png"></a>     |<a href="/examples/user_guide/2_Proximity.ipynb"><img width="1604" src="img/0-2.png"></a>     |<a href="/examples/user_guide/2_Proximity.ipynb"><img width="1604" src="img/0-3.png"></a>     |<a href="/examples/pharmacy-deserts.ipynb"><img width="1604" src="img/0-4.png"></a>|