Thursday, August 9, 2012

Seattle 911 Calls 2011-2012

Step 1: Enter a Seattle address to see 911 calls near that address

Over two years ago I created a thematic map of Seattle Crime data, here. Well, a lot has changed since then. The details of 911 police calls and sometimes incident reports are available from the Seattle Police Department directly, so I decided to create a full blown interactive map to explore the data. Since the department does not report on postal codes or anything other than their district data, I had to implement a google address lookup using javascript. The result is that you can your address and see 911 calls with NNN miles of your specified location.

When you drill into a particular 911 call, look for the blue link in the tooltip to the incident report. This will take you to a Seattle Police website where once registered, you can pull up the incident report. If you get "no report available" it means no report was filed for the 911 call - this is a very normal result.

View source on this page to see the code I used to trigger the call to the Tableau viz. On the sending end, I used the google maps API to retrieve the latitude and longitude given a street address. On the receiving end inside of Tableau, we have parameters for latitude and longitude which can receive input from the URL. Finally, we have a mercator equation which allows you to specify a desired distance from your original address (download the workbook to see that calc).

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