What it is

A map of where you may be able to build ADUs in Ann Arbor

How to do it

Data sources

• City boundaries, zoning districts: City data portal
• Parcels: Washtenaw County

Vector tiles

Using a protobuf Open Street Map extract from protomaps

I used tilemaker to make the basemap tiles

City boundaries

Load into Postgres:

ogr2ogr -f PostgreSQL pg:'user=matth password= host=localhost port=5432 dbname=loveland_geo' -nln ann_arbor -s_srs 'epsg:2253' -t_srs 'epsg:4326' -nlt GEOMETRY -lco precision=NO /Users/matth/Downloads/AA_City_Boundary/AA_City_Boundary.shp

Get the concave hull:

select ST_AsGeoJSON(ST_ConcaveHull(ST_Collect(wkb_geometry), 0.99), 6) from ann_arbor;

Adding zoning to parcels

Load the shapefile to Postgres:

ogr2ogr -f PostgreSQL pg:'user=matth password= host=localhost port=5432 dbname=loveland_geo' -nln mi_washtenaw_zoning -s_srs 'epsg:2253' -t_srs 'epsg:4326' -nlt GEOMETRY -lco precision=NO /Users/matth/Downloads/AA_Zoning_Districts/AA_Zoning_Districts.shp

create index mi_washtenaw_zoning_idx on mi_washtenaw_zoning using gist(wkb_geometry);

update mi_washtenaw p
set zoning = zoningclas
from mi_washtenaw_zoning b
where st_intersects(st_centroid(p.wkb_geometry), b.wkb_geometry);

Render the parcels to tiles using tippecanoe

First, export the data:

ogr2ogr -f GeoJSON mi_washtenaw_parcels.geojson pg:'user=matth password= host=localhost port=5432 dbname=loveland_geo' mi_washtenaw -sql "select * from mi_washtenaw where city='ann-arbor'"

Render the parcels with tippecanoe:

tippecanoe --output-to-directory=parcel_tiles mi_washtenaw_parcels.geojson --read-parallel --include=address --include=zoning --include=ll_gissqft --no-tile-compression -f --coalesce-densest-as-needed --detect-shared-borders --no-tiny-polygon-reduction --simplify-only-low-zooms

To copy it over (I render it in a different directory)

rm -r ../adus/parcel_tiles/; mv parcel_tiles/ ../adus/

Notes and ackowledgements

mapbox/tippecanoe#311 (comment)

Layer name will be mi_washtenaw_parcels

Thanks to klokantech/mapbox-gl-js-offline-example for examples

Thanks to this codepen for mask inspiration