Geocoding Score Documentation: How is the score value determined?

NathanLowry

I know geocoding is largely controled by the Locators .xml files in C:\Program Files\ArcGIS\Desktop10.0\Locators.  However, where is it written (documented in white papers, technical articles, etc.), how the geocoding Score value is calculated?

I'd like to reference the documentation in metadata.

Thanks,

Nathan Lowry, GISP

Governor's Office of Information Technology
GIS Outreach Coordinator, State of Colorado
601 East 18th Avenue, Suite 220, Denver, CO 80203-1494
303.764.7801 720.402.4462 Cell nathan.lowry@state.co.us, http://www.colorado.gov/oit

How am I doing?  Please contact my manager Jon Gottsegen (Jon.Gottsegen@state.co.us) for comments or questions.

JianLiu

Bruce Harold,

Bruce,

Thanks for the insight, this is helpful! I have also been trying to understand the internal algorithm used for ESRI geocoding.

One thing I find strange is that when there are multiple candidates found for an address, the geocoder will pick whatever the first one, instead of the "best" one.

For example, a search for address "2725 30TH STREET SE, Washington DC" will get a match at "2725 30th St NE, Washington, District of Columbia, 20018" with a score of 92.43, when geocoded using ArcMap. The match is wrong, due to the street directional. Of course, a manual rematch will find a 100 match, but this won't be feasible for batch geocoding.

Below shows all candidates returned by findAddressCandidates REST API, but geocodeAddresses will only return the first one that is in fact wrong. The desktop geocoder is the same as geocodeAddresses. I imagine this is done for performance/speed reasons? But this is not right. What can we do to avoid the wrong matches? One options would be to redo the filtering algorithm by picking the biggest score if using findAddressCandidates. But anything for geocodeAddresses? Thanks and it's much appreciated!

Jian

####search for address "2725 30TH STREET SE, Washington DC", return by findAddressCandidates:#####

Address Candidates: (# address candidates : 6)

Shape:

Point:

X:

• -76.9664981241894

Y:

38.92517585657543

Score: 92.43

Address: 2725 30th St NE, Washington, District of Columbia, 20018

---

Shape:

Point:

X:

-76.965586314324

Y:

38.85502946852702

Score: 100.0

Address: 2725 30th St SE, Washington, District of Columbia, 20020

---

Shape:

Point:

X:

-76.96649984530907

Y:

38.92482786588191

Score: 92.43

Address: 2725 30th St NE, Washington, District of Columbia, 20018

---

Shape:

Point:

X:

-77.06011761652377

Y:

38.92385066586513

Score: 92.43

Address: 2725 30th St NW, Washington, District of Columbia, 20008

---

Shape:

Point:

X:

-76.96636920394947

Y:

38.920916363073836

Score: 83.35

Address: 2725 30th Pl NE, Washington, District of Columbia, 20018

---

Shape:

Point:

X:

-76.96552627725934

Y:

• 38.85500159493757

Score: 79.0

Address: 2726 30th St SE, Washington, District of Columbia, 20020