docs: Clarify the usage of xarray engines.

README.md

@@ -1,7 +1,9 @@
-Thalassa
-========
+# Thalassa
 
-[![Documentation Status](https://readthedocs.org/projects/thalassa/badge/?version=latest)](https://thalassa.readthedocs.io/en/latest/?badge=latest) ![GitHub release (latest by date)](https://img.shields.io/github/v/release/ec-jrc/Thalassa) ![CI](https://github.com/ec-jrc/Thalassa/actions/workflows/run_tests.yml/badge.svg)[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ec-jrc/Thalassa/master?urlpath=lab)
+[![Documentation Status](https://readthedocs.org/projects/thalassa/badge/?version=latest)](https://thalassa.readthedocs.io/en/latest/?badge=latest)
+![GitHub release (latest by date)](https://img.shields.io/github/v/release/ec-jrc/Thalassa)
+![CI](https://github.com/ec-jrc/Thalassa/actions/workflows/run_tests.yml/badge.svg)
+[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ec-jrc/Thalassa/master?urlpath=lab)
 
 Thalassa is a library for visualizing unstructured mesh data with a focus on large scale sea level data
 
@@ -31,11 +33,6 @@ Adding support for new solvers is relatively straight-forward.
 ```
 pip install thalassa
 ```
-for Selafin files (openTELEMAC outputs):
-```
-pip install thalassa
-pip install xarray-selafin
-```
 
 ### Conda
 

docs/installation.md

@@ -4,19 +4,14 @@
 
 1. Install the binary dependencies:
 
-    - `python >= 3.9`
-    - `geos`
+   - `python >= 3.9`
+   - `geos`
 
 2. Install from PyPI with:
 
 ```
 pip install thalassa
 ```
-for Selafin files (openTELEMAC outputs):
-```
-pip install thalassa
-pip install xarray-selafin
-```
 
 ### Conda
 
@@ -26,6 +21,15 @@ You can also install using conda/mamba:
 mamba install -y -c conda-forge thalassa
 ```
 
+## Additional file formats
+
+`thalassa` is leveraging `xarray` for reading data.
+If you need to open a file in a format that is not supported by default
+you should install the respective `xarray` engine. For example:
+
+- For GRIB files you should `pip install cfgrib`
+- For Selafin files you should install `pip install xarray-selafin`
+
 ## Obtaining Data
 
 You will need some data to visualize. You can download sample datasets from the following links: