update readme to reflect new make process

in the future, this change will allowe users to swap out zoning data. might need to move the loading of the shapefiles in the jurisdiction folder from the load_data make target to the merge_source_zoning target.

fixup readme.md

README.md

@@ -52,7 +52,27 @@ Then run `make` in the repository directory.
 
 ####Loading/Processing
 
-If you already have the data, then run `make` in the repository directory.
+If you already have the data and the postgis environment set up, then run:
+
+`make load_data`  
+
+This will load most of the above data into Postgres for processing. 
+
+Next run:  
+
+`make merge_source_zoning`
+
+This creates a postgres table with all of the geometries of the source jurisdictional zoning in /data_source/jurisdictional. See [#zoning-data-by-jurisdiction] for more information. 
+
+Next run:
+
+`make zoning_parcel_intersection`
+
+This make target assigns a zoning_id (as found in the data_source/zoning_codes_base2012.csv) to each parcel. Several rules are applied to overcome issues with parcels that within multiple jurisdictions, and/or within multiple zoning geometries. 
+
+###Zoning data by Jurisdiction
+The command `make load_data` extracts the source zoning File Geodatabases to shapefiles in a folder in /data_source/jurisdictional. You can edit inspect and change which data are used by jurisdiction here. Keep in mind that whatever changes you make, each jurisidictional zoning file must have a zoning column which maps to the generic zoning codes and match fields as specified by jurisidction in zoning_codes_base2012.csv and match_fields_tables_zoning_2012_source.csv. 
+Also, all source zoning jurisdiction files are in [EPSG 26910](http://epsg.io/26910). 
 
 ### Outcome