NYCityMap version 3.0

We are in the midst of planning and developing the release of NYCityMap 3.0. The current version, launched in 2010, has had a good run but is showing its age and is in need of a refresh.

As we often try to gather feedback from our audience, this blog post is intended to lay out the basic objectives and to solicit feedback. Follow up posts will be more targeted towards extracting specific input through the use of polls and other online tools.

The basic objectives of the update project are:

  • Responsive design supporting mobile devices;
  • Simplify user interface/presentation of data;
  • Include appropriate existing functionality;
  • Ability to easily update and publish data (for us);
  • Provide a gateway to other mapping applications within NYC;
  • Move away from custom code and leverage a more complete open source solution.

Below are some preliminary screens using OpenLayers 3.0 with tiles generated from ArcGIS Server.

Feel free to comment on this post and send along your feedback on how you would like to see NYCityMap evolve.

NYC Crime Map Tutorial

Click on this link and take a look at the brief video tutorial there. It walks users though the basic functionality of the NYC Crime Map and should be a big help for first time visitors to the site, and even for seasoned users who may have missed something.

NYC Crime Map Tutorial

Screenshot from NYC Crime Map Tutorial

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

Where is the identify tool?

The current release of NYCityMap includes interface updates and addresses issues resulting from the recent update of Chrome (version 29). The interface changes were a result of feedback received and are intended to improve the user experience.

The identify tool was removed; however the functionality still exists. The default tool (Pan) now handles this function similar to Google and Bing Maps. On single left click of the mouse, the tool identifies map features provided the user is zoomed enough to see the feature being identified. On left mouse hold the tool pans the map.

The code changes required due to the Chrome update were related to Dojo widets employed by NYCityMap. These widget were not rendering in Chrome properly. To those who were impacted by this issue, we apologize for the inconvenience. We had made the code changes and were already through testing and ready for release when the Chrome issue struck, We therefore released both changes together.

Well the story does not end there. We have since received feedback from some of our clients critical of the interface changes. We agreed with the feedback and have decided to make additional enhancements as follows:

  • Remove the Pan tool entirely. This will be the default tool (pan/identify/zoom);
  • Add zoom one level on left double-click of the mouse;
  • Add an Advanced Tools button and place within the drag zoom, measure, save map and email a friend tools;
  • Change the Show Aerial Photo tool to a button title Map Type. On click menu items will show the different Aerial Photography years.
  • Change the drag zoom and measure tools to single action (i.e., after single use the tool defaults back to pan/identify/zoom.

These changes are underway and we expect to release these barring any unforeseen issues by the end of the month.

Coinciding with the release of the new New York City hurricane zones (see press release http://on.nyc.gov/12HfnB4) is the release of a new Hurricane Zone Finder application.  The application was developed by NYC Department of Information Technology and Telecommunication (DoITT) in collaboration with the NYC Office of Emergency Management (OEM) and includes improvements over the previous version.

Application improvements include mobile browser support, address search enhancements, multi-modal transit directions and enhanced messaging. Additionally, the transparency of the hurricane zones can be adjusted to clearly display street names and landmarks for better orientation. To do so, click ‘Layer transparency…’ at the bottom of the legend.

NYC Hurricane Zone Finder

NYC Hurricane Zone Finder

The new Hurricane Zone Finder application was developed using Google’s Maps Engine and Maps API. The hurricane zones and evacuation centers are stored in the cloud-based Maps Engine data store and published directly to the Google Maps API. Maps Engine is also queried to determine if the geocoded address is located within one of the six hurricane zones. Maps API and Maps Engine provided the ability to quickly develop an information-rich application while providing the necessary cloud resources to handle the traffic experienced during Hurricanes Irene and Sandy.

The evacuation centers are shown on the map and listed on the Evacuation Centers tab, in ascending order based on distance from the searched address. Directions are provided for each evacuation center or by default for the nearest evacuation center.

Evacuation Center Directions

Evacuation Center Directions

When an evacuation order is announced, the application will specify for which evacuation zones the evacuation order is in effect for. At all other times, the residents of New York City can use the application for pre-planning and preparation.


Today’s snowfall may not have closed the City schools but it brought the third activation of PlowNYC. Developed at the request of Mayor Michael Bloomberg, and in collaboration with the Department of Sanitation, PlowNYC is a web-based mapping application that shows DSNY snow operations progress.

PlowNYC activation on 3/8/2013

Figure 1

Streets are color-coded into time slices that represent the last time a street was serviced by a DSNY vehicle (plow or spreader). Figure 2 shows the time slices and the colors that represent them. Thus, in this case, streets with a color of green have been serviced in the last hour.

PlowNYC Legend

Figure 2

Global Positioning System (GPS) data are received from each equipped DSNY vehicle and transmitted to the operations center. The data is then coded to the street segment it falls on, with the time stamp of the GPS location. The streets are then processed to determine which time slice they fall within and then rendered as map tiles.

Due to the large amount of time required for data processing and map generation, the map is refreshed every fifteen minutes. The last and next update times are shown in the header. In Figure 1, the last update was at 9:45 am with the next update at 10:00 am.

New for this activation is a mobile-web version. Upon loading, individual devices are determined and the appropriate version of the application is served to the end user’s client (web or mobile). The mobile web version is accessed via the same url http://maps.nyc.gov/snow. Figure 3 shows how the application appears on an iPad.

Figure 3

Figure 3

PlowNYC is also accessible from the Office of Emergency Management’s Severe Weather site. the search form shown in Figure 4 is available during a PlowNYC activation.

Figure 4

Figure 4

PlowNYC shares many of the same components as NYCityMap. Geoserver and GeoWebCache are used to access and render the data as tiles. The mobile web version uses OpenLayers.


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