Update readme.

README.md

@@ -3,14 +3,20 @@ Waterstanden
 
 Serves up the most recent water heights in the Netherlands based on the official RWS data. But instead of zips with csvs, a simple json protocol will be used.
 
-## How it works
+Because having public data available is awesome, but zipped csvs are not.
 
-1. Grab the zip file from the RWS server.
-2. Extract the zipfile.
-3. Match the adm file with the dat file.
-4. Filter out everything that's not H10.
-5. Load into a database?Write JSON file?
+## Waterdata
 
-## Why?
+Rijkswaterstaat (RWS) is the Dutch government agency responsible for roads and waterways. They have open data available for the water levels. This is supplied as a zipfile that can be downloaded with a bunch of csv files that contain the waterheights data. Alongside this is an xml with metadata.
 
-Because having public data available is awesome, but zipped csvs are not.
+In order to serve the data up more easily, this application turns the relevant data into JSON and serves it up, removing the need for unzipping and csv and xml parsing.
+
+## Locations
+
+The locations have the following fields:
+
+* lokatie: The abbreviated location name
+* waarde: The last recorded water level
+* omschrijving: A description of the location
+* coordinaten: An x and y coordinate in WSG84
+* laatstBijgewerkt: A silly string representation of the last time the data was updated