add docs chapter visualization

docs/src/SUMMARY.md

@@ -2,10 +2,10 @@
 
 - [Introduction](./introduction.md)
 - [Running & Output](./running.md)
+- [Visualization](./visualization.md)
 - [Model Structure and Resources](./model_structure.md)
 - [Data sources](./data_sources.md)
 - [Analysis](./analysis.md)
-- [Visualization]()
 
 ---
 [Interim presentations](./presentations.md)

docs/src/visualization.md

@@ -0,0 +1,8 @@
+# Visualization
+## Visualizing the model output
+The vector data and the movement of the Bison agents is stored in a file named `Bison_trips.geojson`, the movement of `Moose_trips.geojson` and the movement of the Elk agents is stored in a file named `Elk_trips.geojson`. 
+
+The movement trajectories can be visualized in [kepler.gl](https://kepler.gl/demo). 
+
+Below is a screenshot of the visualization output.
+- [ ] TODO add screenshot