Update readme

README.md

@@ -45,15 +45,28 @@ The swash clipping mask should be checked visually to ensure it is correct.
 Example usage:
 
 ```
-# Process single survey at specific beach
 python las_outputs.py param-files/survey-1-avoca.yaml
+```
 
-# Process single survey at multiple beaches
-python las_outputs.py param-files/survey-1-avoca.yaml param-files/survey-1-pearl.yaml
+### 5. Generate erosion heatmaps
+`generate_heatmaps.py` creates a heatmap raster by calculating the elevation difference between the current and previous surveys.
 
-# Process all surveys at specific beach
-python las_outputs.py param-files/*avoca.yaml
+`generate_heatmaps.py` relies on `arcpy`, so this script must be run using the version of `python` that was installed with ArcGIS.
 
-# Process all beaches for specific survey date
-python las_outputs.py param-files/survey-1*.yaml
+Example usage:
+
+```
+C:/Python27/ArcGIS10.4/python generate_heatmaps.py param-files/survey-1-avoca.yaml
+```
+
+### 6. Export erosion heatmaps
+
+`plot_heatmaps.py` exports a jpg erosion heatmap at all of the beaches covered by the specified heatmap tif.
+
+`plot_heatmaps.py` relies on `arcpy`, so this script must be run using the version of `python` that was installed with ArcGIS.
+
+Example usage:
+
+```
+C:/Python27/ArcGIS10.4/python plot_heatmaps.py param-files/survey-1-avoca.yaml
 ```