Geocoding 101
a crash course in turning localities into lat/lngs
What
is
Geocoding?
| Street_Address | City | State | Zip_Code |
|---|---|---|---|
| 3250 LAKESHORE AVE | OAKLAND | CA | 946102720 |
| 17035 LAUREL RD | MORGAN HILL | CA | 950374415 |
| 635 COLEMAN AVE | SAN JOSE | CA | 951102029 |
| 2100 SANTA ROSA AVE | SANTA ROSA | CA | 954077691 |
| 3649 MT DIABLO BLVD | LAFAYETTE | CA | 945493735 |
| 5000 FOLSOM BLVD | SACRAMENTO | CA | 958194441 |
| 9670 BRUCEVILLE RD | ELK GROVE | CA | 957575950 |
Why Geocode?
What else is possible with this type of data?
Route Optimization
Origin-Destination Matrices
Service Areas & Travel Time Isohyets
Cost
Scale
Rights
How
is
Geocoding
Done?
Census Use Study of 1967
(we like a bit of history, right?)
Network-based
(% along geocoding)
25 Main Street, Dallas, TX 75208
how do you put that on a map?
Search-based geocoding
Geocoding Infrastructure
The New locator.stanford.edu Service
Bulk Geocoding
Gazetteering
Reverse Geocoding
1.67 million geocodes per hour
Geocoding APIs & Services
Specialty Geocoding APIs:
- Yandex - Geocoding and Routing API for Russia, Eastern Europe and Western Asia.
- MapMyIndia.com - Geocoding and Routing API (plus many others!) for India
Esoteric localities...
Chambers Spring Road 2.5 km S of Hwy 412, 8.0 km E of Siloam Springs, T17N, R33W, Sec. 18
Tulane's Geolocate Infrastructure can handle this...
Most important, Geolocate emphasizes the idea of 'uncertainty' in geocoding
The Data
250+GB of Parcel, Street, POI & Administrative Boundary Data
Street-level address data for 149 countries that covers more than 90% of the world's population
Millions of businesses, landmarks, and other points of interest for "Reverse Geocoding"
Topologically Integrated
Thinking about geocoding...
Things GIS hates about your tables:
- Spaces or special characters (other than _ ) in field names
- Field Names that start with a number
- Empty Rows
- Merged Cells
- Excel Formulas
Specifics on tabular data for geocoding
- Most geocoding services prefer street addresses in a single field, with City, State, Postal Codes, etc... in separate fields.
- For placenames, concatenate administrative units, as follows:
Dallas, Tx, USA
Collapse your addresses/placenames into a table of UNIQUE addresses/placenames!
https://locator.stanford.edu/arcgis/rest/services/Geocode/NorthAmerica_Composite/GeocodeServer/findAddressCandidates?f=pjson&singleLine=397%20Panama%20Mall,%20Stanford,%20CA%2094305
Geocoding 101
By Stace Maples
Geocoding 101
A Crash Course (because this is a workshop in progress, and geocoding is hard and we will crash a little).
