NYC Crime Map

On December 8, 2013 New York City launched the NYC Crime Map. In collaboration with the NYC Police Department, the NYC Crime Map was developed in-house by DoITT GIS staff using Google’s Maps API, Places API and Maps Engine.

The application went through multiple rounds of intensive code reviews with Google engineers and rigorous regression testing by DoITT Quality Assurance staff. Map Engine Query Per Second (QPS) and Query Per Day (QPD) limits were increased to accommodate the expected high volume of traffic. These measures were taken to ensure a smooth release and positive experience for the users.

The application follows a responsive web design approach and is therefore optimized for most modern smartphones, tablets and desktop computers. The screenshots below demonstrate the layouts in a desktop browser and iPhone.

Crime Map

Crime Map in desktop.

Crime map in iPhone.

Crime map in iPhone.

To protect privacy, crime data are located at the nearest intersection of a crime or the midpoint of a City block (approximately a street defined by two intersecting cross streets) for crimes occurring at a discrete addresses. For a detailed description of the data methodology, see the About page.

Crime can be visualized as graduated points, shaded precincts (i.e., choropleth) or a heat map. The graduated point view renders the data as points varying in size by the frequency of crimes at that specific location. In this way, locations with greater occurrence of crime will have a larger point. The precinct map aggregates the crime to the precinct level and normalizes the data showing aggregate crime rates (crimes per 1,000 people). The precinct view provides a city wide view of the data and allows for comparison of crimes across the different precincts that make up NYC. The heat map uses the Google Map API heatmap function to show the relative concentration or intensity of crime.

Local Law 39, passed by the City Council in May,2013, was the basis for the interactive crime map. This legislation provides the public with a more detailed view of crime within NYC than previously possible. As per the legislation, crime data is available for the current year and previous year and is aggregated by month, year to date and full year. The data will be updated monthly as it is received.

Press release.

Interface changes

The previously mentioned NYCityMap interface changes are now live. These changes reflect usability improvements and address feedback received. The result is the preservation of existing functionality while streamlining the user interface. The changes are:

Addition of an Advanced tool. Within this are the previous tools that existed over the base map.

Advanced Tool

Replacing the slider with Map Type tool. Many users were confused by the slider and the ability to toggle between a cartographic map (Map) and the numerous years of aerial photography. All of these base maps still exist but are are now within the Map Type tool. The base map selected is shown by a check next to the entry.

Map Type