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Posted on Wed, Feb 17, 2010 : 10:33 a.m.

City of Ann Arbor open data catalog published

By Edward Vielmetti

The city of Ann Arbor has released a new data catalog with dozens of new sets of published municipal data. Ann Arbor joins Portland, San Francisco, Vancouver and New York City in making this information widely available in raw formats.

Here's a guide to what's there.


Ann Arbor Police Department calls for service. There are 5,813 records in this database today, reflecting data starting Jan. 4 and ending Feb. 5. For each record, there is the police log number, the date of the complaint, the date of the incident, the type of incident and an approximate location.

The most frequent codes in this log are "traffic miscellaneous" (1,810 entries), "traffic crashes - property damage" (295 entries), "parking complaint" (284 entries), "burglary alarm" (187 entries), and "suspicious persons" (185 entries). A total of 848 of these records are logged as "open generic," a code I don't know how to interpret.

The location for each of these incidents is coded either as an intersection or as a block of a street. The block based reporting is designed not to provide unwarranted invasions of personal privacy. The most frequent locations in this data set are 3000 block of Washtenaw Avenue (79), the 100 block of Fifth Avenue (police headquarters, 65), Plymouth Road and Barton Drive (61), the 1000 block of "University Ave" (55), and the 300 block of Maynard Street (police substation, 41). Note that the report does not distinguish between North University, South University or East University, and that street locations with numbers greater than 1000 are aggregated into superblocks (1000-1999), whereas places closer to town are more precisely located (300-399).


The city and the county released a set of maps, most of which are available in both KML and shape file formats. They include the boundaries of all cities and townships in the county and the Ann Arbor Downtown District Authority, parcels of city-owned land, all parks and nature preserves countywide, city greenbelt properties, rivers, streams, lakes, the floodplain and floodway, zoning, historic districts, open spaces and land use, ward and precinct boundaries and polling places, schools and school districts, hospitals, county board of commission districts and roads.

It's a great collection for a start. The schools information is at the district level, so it doesn't show what the elementary and middle school and high school assignments are for a given location, for example. I wish that I had a similar zip code map, and I also wish there was a map of library districts in the same formats.

Financial information

The finance and administrative services department is publishing a monthly investment report, budget information, accounts receivable, a check register, purchase orders and purchase card transactions.

The purchase card transactions report has 7,059 records, with 2,781 from 2008 and 4,277 from 2009. There are no records in it from 2010. The most frequent transactions were from Lowes (665), Stadium Hardware (359), Gordon Food Service Marketplace (159), Carpenter Bros. (145), Home Depot (141) and Napa Auto Parts (130). I haven't totaled up all of the numbers yet.

Other data sets

The city clerk is publishing permits, mostly dog licenses and block party and noise applications.

The communications office has a calendar.

Planning and development has more permits, including construction underway and applications for review.

What to do with all this data

There are other municipalities with similar collections of open data, including Washington DC, San Francisco's DataSF, Vancouver and New York City.

The ReadWriteWeb blog discusses Portland, Oregon's plans to publish open data, asking: 

 "What US city will move in favor of open source and open, structured data next? Seattle? New York? Someplace in the Mid West? Place your bets now as these are unlikely to be isolated developments."

I'm looking forward to seeing what we - and you - come up with to interpret all of this.

Edward Vielmetti is the lead blogger for Contact him at 734-330-2465 or



Sat, Feb 20, 2010 : 4:40 p.m.

Excellent work. Some of the financial data raises a concern: "The most frequent transactions were from Lowes (665), " May I suggest we try to buy from local companies whenever possible? At the very least, perhaps local companies could have a right of first refusal? Multinationals have little loyalty to anyone... Thank you. Open data empowers the citizens.

Kathy Griswold

Wed, Feb 17, 2010 : 3:28 p.m.

This is great news. I hope AAPS will start posting similar "raw" financial data.

Andrew Turner

Wed, Feb 17, 2010 : 11:33 a.m.

Superb work! Open data in a variety of formats is very well done and needed. Something that would be useful is an Atom feed linking to the datasets so people can watch for updates. You may want to check the metadata and licensing for some of the datasets. For example, the School Boundaries dataset has the following license that doesn't seem to fit in a public data catalog: "This data set is intended for internal use by Washtenaw County government. Use for any other purpose must be approved by Washtenaw County GIS, and a Data Dissemination Agreement must be signed between Washtenaw County and any involved parties. Please contact Washtenaw County GIS for information about Data Dissemination Agreements"