Sam Wear — one of New York’s pre-eminent GIS leaders — published a fun interview with me about our mapping work at the CUNY Graduate Center. I’m honored!
UPDATE Sept 7, 2012
The City Council Comparinator site is now embeddable for your website, blog, etc.
Here’s how to use it:
- go to the site,
- zoom to a district and click to highlight it (or enter a street address),
- choose one of the tabs above the map (Side-by-Side vs Overlay, for example), and
- pick which proposal you’re comparing with (Districting Commission or Unity Plan).
- Then click “Link” in the upper right and you’ll see the embed code as well as the basic linking code.
Sample embed code:
- < iframe width=”600″ height=”450″ frameborder=”0″ scrolling=”no” marginheight=”0″ marginwidth=”0″ src=”http://www.urbanresearchmaps.org/citycouncildistricts/map.html?lat=40.75935&lon=-73.81138&zoom=14&identify=-73.805799628444%2C%2040.755706832582&popup=false&maptype=OVERLAY&districttype=UNITY1&attributelayer=Plurality2010&output=embed“></iframe >
We also added a feature: if you turn off the popup window before clicking “Link”, it’ll add a “popup=false” property to the URL, so the person viewing the link (or the starting image for your embedded map) won’t have the popup in the way but the district will still be highlighted.
Here’s an example:
- Link: http://www.urbanresearchmaps.org/citycouncildistricts/map.html?lat=40.75935&lon=-73.81138&zoom=14&identify=-73.805799628444%2C%2040.755706832582&popup=false&maptype=OVERLAY&districttype=UNITY1&attributelayer=Plurality2010
ORIGINAL POST Sept 5, 2012:
NYC Council Districting and You
How existing City Council districts compare with proposed lines
Our Center for Urban Research (CUR) at the CUNY Graduate Center has launched an interactive map today to visualize proposed New York City Council districts compared with existing ones along with the demographic characteristics and patterns within the districts.
The Center hopes the map will help involve people in the NYC districting process simply by showing them how proposed or newly drawn lines looked in relation to their homes or workplaces. Our map is not for drawing districts; others such as the NYC Districting Commission are providing that service. But CUR’s comparison maps are designed to be be engaging enough to visualize the impact of redistricting for everyone from local citizens to redistricting professionals, hopefully inspiring people to participate more actively in the process.
CUR’s map was designed and is being maintained independently from the NYC Districting Commission’s website. However, we hope that people who use CUR’s maps will then access the Districting Commission’s website for drawing maps online.
Using the map
The main features of the map are as follows:
- Enter your address to find out what district currently represents you, and which proposed district you’d live in.
- If you’re using the “Side-by-Side” view, the current districts are displayed on the left, and the proposed districts on the right.
- If you’re using the “Overlay” view, you can move the transparency slider to the right to display proposed districts, or to the left to fade back to current districts.
- Click anywhere on the map to highlight the current and proposed districts.
- When you enter an address or click on the map, an info window pops up listing the current and proposed districts. You can click the link for the current district to go to that Councilmember’s website.
- Click the “Link” in the upper right of the page to get a direct link to the area of the map you’re viewing. (This one zooms in on City Council District 8 in Manhattan.) You can share this on Twitter or Facebook, email it to friends and colleagues, or blog about it and include the link.
The mapping application was developed by the Center for Urban Research. David Burgoon, CUR’s application architect, constructed and designed the site, with data analysis support and overall conception from CUR’s Mapping Service director Steven Romalewski.
The application relies on geographic data hosting by cartoDB, open source mapping frameworks and services including OpenLayers and Bing maps, and ESRI’s ArcGIS software for cartography and data analysis.
Current City Council district boundaries and proposed maps from the NYC Districting Commission are based on block assignment lists provided at the Districting Commission’s website.
Other proposed maps such as the Unity Map are provided by the advocacy organizations who developed those proposals.
In partnership with the Long Island Index, our team at the CUNY Graduate Center has mapped the complex and complicated special taxation districts and service provider areas throughout Nassau County. We’ve updated this information at the Index’s mapping site, along with a new street address search feature.
I couldn’t say it any better than the Index’s news release on the project, so I’ve reproduced that verbatim below.
Nassau County’s Special Districts and Service Providers Mapped for the First Time
The Long Island Index, in collaboration with the Center for Urban Research at the CUNY Graduate Center, launched a new tool on its website that for the first time provides public access to maps representing the profusion of special districts that exist within Nassau County’s villages and towns. Visitors to the site are now able to search by street address or village to view any or all of the 240 fire, sanitation, water, library, parks, parking, police, school and sewer districts – as well as areas where local, county, or state government provides these services – and see clearly who provides what services and where. This new tool is the result of a comprehensive project to delineate all service provider boundaries using computer-mapping software, which integrates data on special districts from multiple sources. The maps are intended to give taxpayers and service providers a common and consistent basis for discussing special district issues.
The Long Island Index’s new mapping tool allows visitors to view any or all of the 240 fire, sanitation, water, library, parks, parking, police, school and sewer service providers in Nassau County.
Want to know how many different entities provide water services in Nassau County and their exact boundaries? Well, now you can see them. Want to know who provides water services in your community? Want to know how they are organized, which are special districts, which are town services? You can find that too. With the click of the mouse you can find the contact information and election data for all the service providers for your property. “This is the kind of tool we were looking for when we first started studying how services are provided on Long Island,” said Ann Golob, Director of the Long Island Index. “It didn’t exist so we took on the effort and have worked for over two years to collect, analyze and digitize this information. I think it will be a tremendous resource for the region.”
Also available on the site is a report by the Center for Governmental Research (CGR) in Rochester that explains the historical context surrounding the founding of special districts on Long Island along with the issues associated with so many providers. The CGR report, and the data found on the maps (provider names, URL, contact information, election data) can be downloaded from the either the Index Web site or the interactive maps site.
Steven Romalewski, director of the CUNY Mapping Service at the Center for Urban Research, said: “The maps bring a new level of information which will be a valuable resource for anyone trying to understand how special districts affect them. To create the service provider maps, we used raw data from the Nassau County assessor’s office, worked with the Index to validate the information independently, and reviewed additional data such as printed maps, historical metes and bounds, and some boundary maps in computer format from Nassau County. The online navigation is quick and easy with dynamic tools such as transparencies and map layers that combine seamlessly with the existing demographic, land use, and transportation data on the site.”
The site also features a detailed glossary of terms to help people understand the complex nature of different special districts across the county. For example, within the 54 library districts in Nassau County, there are four types: an Association Library, a School District Public Library, a Special District Public Library, and a Public Village Library. The glossary explains how each of these were established, how they are funded, bonding authority, if employees are subject to civil service law, and to what extent the community can be involved.
According to Long Island Association President Kevin Law, “These maps give Long Islanders a fantastic new tool for understanding the complexities that exist within our numerous special districts. It is really the first time that we can see who has what and where. It provides an opportunity to think out of the box about consolidation, which has the potential to improve efficiencies and stabilize taxes. People are only going to be supportive of this kind of initiative if they understand what is going on and these maps clearly show how multiple layers of government are a challenge for Long Island.”
“Civic organizations trying to research special districts in their own communities now have a powerful resource that never existed before,” said Nancy Douzinas, President of the Rauch Foundation and Publisher of the Long Island Index. “These maps will undoubtedly be of significant assistance to community groups, government agencies, private businesses and anyone else interested in Long Island’s communities.” In addition to the support from the Rauch Foundation, the Hagedorn Foundation helped support the initial mapping work leading to this project.
The Long Island Index plans to incorporate Suffolk County’s special districts in the coming months. The Long Island Index special district mapping feature is accessible at www.longislandindexmaps.org.
UPDATE Nov. 5, 2012
In preparation for the Nov. 2012 election, many news organizations and others are linking to our interactive State Legislature and Congressional redistricting maps. We’ve posted examples at the Center for Urban Research website.
We’ve updated our map of redistricted State Senate and Assembly districts, highlighting the differences in race/ethnicity characteristics between total population and voter-eligible population – in other words, comparing the characteristics of all those who live in the new districts versus the smaller group who will be eligible to vote for each district’s representatives. In some cases the differences are striking.
Our examination of the district-by-district data is available here.
New York State, like all other states, is in the midst of redrawing its legislative district lines. To help you follow along, our team at the Center for Urban Research has launched an interactive redistricting map for New York. We collaborated with The New York World to develop the maps (though we encourage anyone and everyone to use them!).
The World’s reporters and editors are using our maps to go between the lines and explain how redistricting really works in the Empire State. (Here’s their first piece: The art of redistricting war.) And we hope you’ll be able to use the maps too, to help answer questions such as:
- Will you still be represented by the same State Senate or Assembly district you live in now?
- Will you live in the newly proposed (and controversial) 63rd Senate district?
- Is your neighborhood, town, or county going to be “carved up” by a new legislative seat?
- Will your community’s historical voting power be diluted by the new districts?
We have some examples of gerrymandering at our Center’s website. In the meantime, here’s how you can use the maps.
- Enter your address to find out what district currently represents you, and which proposed district you’d live in.
- The current districts are on the left, and the proposed districts on the right.
- You can also click on either map to highlight the current and proposed districts. As you move one map, the other moves in sync.
- When you enter an address or click on the map, an info window pops up listing the current and proposed districts. You can click the link for the current district to go to that Senator or Assemblymember’s website.
- Switch between State Senate and Assembly districts. Congressional districts will be posted once the data is available from LATFOR.
- You can zoom in to street level, or zoom out to a statewide view. Switch between a street basemap or an aerial view from Microsoft’s Bing maps to see geographic details.
If you’re using the “Overlay” view, you can move the transparency slider to the right to display proposed districts, and to the left to fade back to current districts. The video below shows how:
If you want to share the map you’ve made, click the “Link” in the upper right of the map page to get a direct link to the area of the map you’re viewing. It will look like this:
http://www.urbanresearchmaps.org/nyredistricting/map.html? lat=40.72852&lon=-73.99655&zoom=13&maptype=SIDEBYSIDE &districttype=SENATE
- You can share this on Twitter, Facebook, etc and email it to friends and colleagues.
- You can also embed the map at your site. Use this link …
- … or add < &output=embed > to any of the direct links you create, like this:
http://www.urbanresearchmaps.org/nyredistricting/map.html? lat=40.72852&lon=-73.99655&zoom=13&maptype=SIDEBYSIDE &districttype=SENATE&output=embed
- … or wrap the snippet below in an iframe tag (I’d wrap it myself, but wordpress.com strips out iframe tags):
src="http://www.urbanresearchmaps.org/nyredistricting/map.html?output=embed" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" width="600" height="700"
Side-by-side maps with OpenLayers
We borrowed from our “Census Comparinator” mapping site that Dave Burgoon artfully developed, in order to provide three ways to compare the current and proposed legislative districts:
- a side-by-side view — two maps that are synced and move as one;
- an overlay — a single map where you can fade between current and proposed districts; and
- the vertical “before-and-after” slider approach.
With Census data, our “Comparinator” approach helped visualize changing spatial patterns of race/ethnicity trends – in cartographic terms, between two choropleth maps. With legislative districts, the comparison is between two sets of boundary files with no inner fill. So here we’ve set the side-by-side view as the default — we think the side by side maps give the easiest way of visualizing how the districts may change. But we also give you the option of viewing the districts with our vertical slider bar if you’d like, or the overlay.
Behind the scenes
For the proposed districts, we used ArcGIS to create the legislative district shapefiles based on LATFOR’s Census block assignment lists. The current district boundaries are from the Census Bureau’s TIGER files (here’s the FTP page if you’d like to download the “lower” house districts — in New York, that’s the Assembly — or the “upper” house shapefiles — the State Senate).
That said, newer approaches such as Leaflet.js enable more interaction such as mouseovers, so we’ve started experimenting with some impressive new tools. More to follow!
One of those new tools is the powerful backend geospatial database engine from the team at Vizzuality: cartoDB. Hosting the legislative district shapefiles on cartoDB provided lots of advantages over hosting the data ourselves or setting up an Amazon cloud instance on our own. cartoDB provides:
- great performance — not only for the district boundaries, but soon we’ll be adding election district maps to show voting patterns within each Senate and Assembly district. We don’t want to bother with creating pre-rendered tiles for this data. cartoDB will render it speedily on the fly.
- cartographic flexibility: cartoDB uses cartoCSS for map symbology and labeling. Though there are still some quirks with cartoCSS, it was easy to grasp and it’s basically just CSS, so it makes styling easy if you’re familiar with modern web design. And cartoCSS incorporates scale-dependent rendering as well as attribute-based symbology, which makes it powerful and flexible. CartoCSS can be implemented using the cartoDB management interface, or programmatically.
- easy data management: if you know SQL — and even better, if you’re familiar with SQL commands with PostGIS — you can quickly and easily modify tables, filter data, and perform spatial operations. (The screenshots at the cartoDB github page offer some examples.) Very cool.
- scaling: cartoDB uses PostGIS and makes use of Amazon’s platform. So if our maps go viral, we’re ready for the usage spike!
- open source: if you want to manage your own instance of cartoDB, just download the code and go! Big props to Vizzuality for an amazing geospatial toolkit.
Other thanks go to:
- LATFOR, the state’s redistricting task force. Whatever you think about their redistricting process, they’ve done a great job with open data. They’ve not only posted the list of Census blocks that make up each proposed legislative district. But they also posted a wealth of data at the Census block level and also at the election district level (with a crosswalk between EDs and Census “voter tabulation districts”). This data is indispensable for visualizing, analyzing, and (hopefully) making sense of the new districts.
- Dave Burgoon and the CUR team. Dave put together the redistricting mapping site in record time. Although it’s based on work he had already done with the Census Comparinator maps, it still involved substantial modifications and enhancements. But he made it happen as professionally and elegantly as always.
- The New York World. We had been planning to create an interactive mapping application to build on our Census Comparinator site and to help people visualize the impacts of the redistricting process and demographic changes more broadly. But the World team – Alyssa Katz, Michael Keller, and Sasha Chavkin – met with us a few weeks ago to discuss how we could collaborate on analyzing and mapping the upcoming district proposals from LATFOR. The discussion inspired us to roll out a mapping site specific to New York State and focused on comparing the current and proposed districts. We’re thrilled to be able to work closely with them on this project (watch for more maps and data in the near future!).
- The Hagedorn Foundation. The Foundation has provided funding support for our efforts to map and analyze Census data for a variety of civic engagement purposes, especially for Hagedorn’s Long Island-based grantees but also nationwide. Their support has been essential for us to develop innovative mapping applications like the NYS redistricting maps – not to advocate specific district plans one way or another, but to give local residents and others the tools they need to understand the impact of redistricting and hopefully get involved in the process.
Our team at the CUNY Graduate Center has enhanced the OASISnyc.net mapping site with new data and features to visualize neighborhood change across the city. On the eve of the 10th anniversary of 9/11, the updates help provide context for the transformation taking place in lower Manhattan, as well as in other key areas of the city.
I’ve only included some of the highlights below. Our OASIS wiki has more details plus screenshots and other examples.
2010 Aerial Imagery
We’ve added new aerial imagery, thanks to the NYS GIS Clearinghouse. Now you can view overhead images from 2010 (as well as 1996, 2004, 2006, and 2008) throughout New York City and Long Island. (The 1996 imagery is from NYC DoITT, 2004 is from USGS, and the other years are from the NYS GIS Clearinghouse).
For example, you can see what the World Trade Center site looked like from above in 1996, and then in 2006, and more recently in 2010. The overhead images show clearly how the building footprints are reflected in the memorial plaza fountains now under construction.
Visualize Aerial Photo Changes like a Timelapse Movie
We’ve also changed the way you can view the imagery over time. Now you can move the aerial timeline slider across years to transition from one year to the next, creating the effect of a timelapse movie within the OASIS map.
You can move the slider as slow or as fast as you’d like.
A good example of the new timelapse feature is Shea Stadium (now Citi Field) in Queens. The images below illustrate the transition in recent years.
Shea Stadium (2006)
Shea Stadium (2006-08)
Citi Field almost done (2008-10)
Citi Field (2010)
Land Use Changes Citywide
Since 2010, OASIS has provided the ability to display historical land use patterns (for 2003 through 2009). This gives you the ability to easily see how patterns have changed in key areas of the city.
In lower Manhattan, the area around the World Trade Center site has changed substantially in the past 10 years. Of course reconstruction is underway at the WTC site itself, but the surrounding community has become much more residential. The land use maps below from OASIS visualize some of these changes (yellow and orange are residential properties, brown is vacant, and light red is commercial).
North Battery Park City & TriBeCa vacant land (and WTC empty): 2003
Residential towers built, WTC site in redevelopment
The maps below highlight the changes from commercial office buildings to residential towers, such as the block between Broad and Hanover streets & Wall and Exchange streets — especially the JP Morgan Building at 15 Broad St and the National City Bank Building at 55 Wall St.
Financial District commercial property circa 2003
Replaced by residential by 2010
More Community Data
The latest example of linking mapped information from grassroots groups is the layer of skate parks in the city by longtime OASIS partner Open Road of NY. (The OASIS community mapping effort is based on Google’s new Fusion Tables service; more info here.)
Our team at the Center for Urban Research (at the CUNY Graduate Center) has updated our interactive maps showing race/ethnicity patterns from 2000 and 2010 in major cities across the US. We’ve enhanced the maps in several ways:
- Added more cities. We now have 15 major urban regions mapped across the US (Atlanta, Baltimore, Boston, Charlotte, Chicago, Detroit, Houston, Los Angeles, Miami, New York, Orlando, Philadelphia, Phoenix, San Francisco, and Washington D.C.).
- The maps now have three ways of comparing 2000 and 2010 racial patterns:
- a vertical slider bar dividing two overlapping maps (2000 on the left, 2010 on the right);
- a side-by-side comparison (two separate maps moving in unison), and
- a single-map overlay (you can fade between 2010 and 2000).
Here’s our news release with more info.
Btw, we’ve also updated our static maps to show New York City Council districts, to begin to get a sense of how demographic changes will shape upcoming redistricting efforts at the local level. Here’s the link:www.urbanresearchmaps.org/plurality/nyccouncil.htm (For the static maps, you can view 2000-2010 demographic change with the vertical slider bar, but you can’t zoom in/out, etc.)
An initial version of the maps launched in June with the vertical bar technique, integrating it with interactive, online maps for the first time. Our Center crafted the maps so you could not only drag the bar left and right but also zoom in and out, click on the map to obtain detailed block-level population counts, and change the underlying basemap from a street view to an aerial image (via OpenLayers use of Microsoft’s Bing maps tiles), while also changing the transparency of the thematic Census patterns.
The latest iteration of CUNY’s Census maps continues to use the vertical slider but now incorporates this technique with two more comparison options. Each approach serves different purposes:
- The vertical slider bar provides a “before (2000) and after (2010)” visualization of change, either regionally or at the scale of a city neighborhood.
- The side-by-side comparison is ideal for lingering over a given area, especially at the local level, taking the time to absorb the differences in demographic patterns mapped with 2000 Census data on the left and 2010 on the right. We incorporated this approach specifically at the suggestion of the great interactive team at the Chicago Tribune, who have created some similar Census maps.
- The single-map 2010/2000 overlay is especially helpful for revealing the increase in diversity over a given area.
For example, you can zoom to Atlanta, GA on the single-map overlay and see the city’s predominantly Black population in 2000 surrounded by suburban Census blocks shaded dark blue, denoting a White population of 90% or more (see images below). As you transition the map from 2000 to 2010, the dark blue in the suburbs fades to a lighter shade (indicating a more mixed population demographically) coupled with more Census blocks shaded green, purple, and orange – each corresponding to communities that are now predominantly (even if only by a few percentage points) Hispanic, Asian, or Black respectively. This pattern is replicated in many of the urban regions featured at the website.
Atlanta & suburbs in 2000
Race/ethnicity change in Atlanta by 2010
Eventually we’ll be moving all this from pre-rendered tiles to vector tiles. CUR’s application architect Dave Burgoon contributed code he developed to TileStache to enable TileStache to produce AMF-based output for use in Flash-based interactive mapping applications. This will give us flexibility in mapping as many Census variables as needed, and also providing complete geographic coverage (hopefully down to the block level) nationwide. That’s the plan, anyway! Stay tuned.
Funding for much of the Center’s recent work on Census issues has been provided by the Building Resilient Regions Project of the John D. and Catherine T. MacArthur Foundation, the Hagedorn Foundation, as well as support from the CUNY Graduate Center and the City University of New York.
Several people provided feedback and helpful editorial suggestions on earlier versions of the maps and narrative. Though the materials at this site were prepared by the Center for Urban Research, those invdividuals improved our work. We greatly appreciate their contributions.