CategoryMaps

How much of the land within walking distance of a CTA station is zoned to allow multi-family housing?

I recently created the Zoning Assessment tool on Chicago Cityscape, which shows a map of aggregated zoning districts in a given community area, ward, or near a CTA or Metra station. Per Paul Angelone’s suggestion, you can now show the walk shed – the area within walking distance to the station, following the streets.

The maps in this post show where one can build apartments (including a simple and common two-flat) within a 15 minute walk to the Logan Square Blue Line station, which has 24-hour service. Try it yourself.

Thirty-one percent of the walk shed allows multi-family housing.

In a second version of the same map, I’ve marked in red the gaps in the zoning map. These are areas that are zoned to allow only single-family housing. That doesn’t make sense: The land near rapid transit stations should be much denser than the land away from the stations.

Sixty-four percent of the walk shed allows only single-family housing. The remaining five percent are planned developments (at least the Mega Mall is going to have a couple hundred dwelling units), manufacturing, and parks.

And if most of the block is already zoned to allow multi-family housing, why are these parcels skipped?

This is the same map as the one above, but with areas that allow only single-family housing marked in red (however, I skipped some areas to save myself time).

How it works
The walk shed boundaries are generated by Mapzen’s isochrone service. The Zoning Assessment map asks Mapzen for the polygon of a specified walk shed (walk or bike, 10 or 15 minutes), receives the polygon and sends that polygon to a custom API on the Cityscape server, which compares that to the server’s copy of Chicago’s latest zoning map. The comparison is then returned to the browser and replaces the default Zoning Assessment map.

How to download data from ArcGIS MapServers using your computer’s command line

A lot of geospatial data (GIS) is stored on ArcGIS MapServers, which is part of the Esri “stack” of products that municipalities use to manage and publish GIS data. And a lot of people want that data. If you have ArcGIS software on your Windows computer, then it can be pretty easy to plug in the map server URL and manipulate and extract the data.

For the rest of us who don’t have an extremely expensive license to that software, you can use a “command line” tool (written in Python) on any computer to download any layer of GIS data hosted on the ArcGIS MapServer and automatically convert it to GeoJSON.

You’ll need to install the Python package pyesridump, from the OpenAddresses GitHub repository, created by Ian Dees and other contributors.

Installing pyesridump is easy if you have pip installed, using the command pip install esridump.

The next thing you’ll need is the URL to a layer in a MapServer, and these are not easy to find.

Finding data to download

I can guarantee the county where you live has one. Before you continue, check to see if your county (or other jurisdiction) has the “open data portal” add-on to their ArcGIS stack.

Here are links to the open data portals enabled by Esri for Lake County, Illinois, and Broomfield County, Colorado). This is much easier to browse and find data to download (in shapefile and other formats) and you can skip this tutorial.

I don’t have a good recommendation to find the MapServer URL, though. A reader suggested looking for MapServers for jurisdictions around the world by looking through Esri’s portal of open data called ArcGIS Hub. Once you locate a dataset you want, you can find the MapServer URL under About>Data Source on the right side of the page.

I normally find them by looking at the HTML source code of a MapServer I already know about.

For this example I’ll use one of the GIS layers in the Cook County, Illinois, election service MapServer – here’s the layer for the Cook County commissioners districts.

Fetch the data

Once you have the URL the command is simple:

esri2geojson http://cookviewer1.cookcountyil.gov/ArcGIS/rest/services/cookElectnSrvc/MapServer/11 cookcounty_commissioners.geojson

  • The first term, esri2geojson tells your computer which program to load.
  • The second term is the URL of the MapServer URL.
  • The third term is the filename and location where you want to store the file. I prefer running the command “inside” the folder where I want the file to be stored. You can also specify a full path of the file. On a Mac this would look like ~/Users/username/Documents/GIS/projectname/cookcounty_commissioners.geojson

After you enter the command into your computer’s terminal, press enter. esri2geojson will report back once, after it finds and understands the MapServer URL you gave it. When it’s done, the command will “close” and your computer’s terminal will wait for the next command.

Do you have questions, or need some help? Leave a comment below.

A map of maps

The map of maps.

Over on my website Chicago Cityscape I’ve assembled a map of maps: There are 20,432 maps in 36 layers. You might say there are 36 maps, and each of those maps has an arbitrary number of boundaries within. I say there are 20,000+ maps because there’s a unique webpage for each of them that can tell you even more information about that map.

This post is to throw out some analysis of these maps, in addition to the simple counts above.

The data comes from the City of Chicago, Cook County, and the U.S. Census Bureau. Some layers have come from bespoke sources, including the entrances of CTA and Metra stations drawn by Yonah Freemark and me for Transit Explorer. The sections of the Chicago River were divided and sliced by the Metropolitan Planning Council. The neighborhood and business organizations layers were drawn by me, by interpreting textual descriptions of the organizations’ boundaries, or by visually copying an organization’s own map.

There are 6,879 unique words longer than 2 characters, in the metadata of this map of maps. The most common word is “annexation”, which makes sense, given that the layer with the most maps shows the 10,668 Cook County annexation actions since 1830 – the first known plat was incorporated in the City of Chicago.

The GeoJSON file, an open source, human readable GIS format, comes out to 30 MB, and it make break your browser when you try to display this layer.

The next group of words are also generic, like “planned” and “development”, related to the Planned Development kind of zoning process in Chicago – called Planned Unit Development in other jurisdictions.

After that, some names of municipalities that traded back and forth between unincorporated Cook County and incorporated municipalities are on the list.

Working down the list, however, it gets really boring and I’m going to stop. I bet if you’re a smarter data science person you can find more interesting patterns in the words, but I’ve also increased the number of generic words (like planned development) by adding these as keywords to each map’s “full text search” index, to ensure that they would respond to a variety of search phrases from users.

Designing a new static map style for Chicago Cityscape

I redesigned the static maps that are shown on Chicago Cityscape’s Place pages to tone down their harsh hues, and change what data (which comes from OpenStreetMap) is shown.

All 2,800 maps are automatically generated using a program called MOATP (“Map of all the places”) which is based on Neil Freeman’s svgis program. Both programs are open source.

The map now shows all roads; it was awkward to see so many empty spaces between buildings. Secondary* and residential roads are shown with slightly less thickness than primary and motorway roads. Also included are multi-use trails in parks.

Parks and grass are shown in different hues of green, although I don’t think it’s distinctive enough to know there’s a difference. Cemeteries remain a darker green.

I’ve changed the building color to soften the harsh brown. Only named buildings and schools appear, which is why you see a lot of gaps. Most buildings outside downtown aren’t named.

Retail areas have been added in a soft, salmon and tan-like color to show where “activity” areas in each Place.

I’ll be uploading the new maps soon.

* These road categories come from the OpenStreetMap “highway” tag.

Chicago’s ward boundaries should go down alleys instead of main streets

Dividing a small part of a business district, centered on one street, into three fiefdoms cannot be an efficient way to govern a neighborhood, aggregate resources, or provide services.

This graphic illustrates how many elected “stakeholders” – each with their own ideas – a city transportation department and its contracted engineers have to deal with to repave a street and rebuild the sidewalks.

The constituents are the same, however. They are all small business owners, and if you want to get together and advocate for change, you’ll have to make three different appointments.

Say the first elected official supports your small group’s proposal. Are they going to talk to the next door elected official and collaborate?

Naw. Not in Chicago. This is the city where a bike lane will be repaired on a street, but only up to the point where the fiefdom boundary ends, because the next official didn’t want to pay for the maintenance on their side.

I can see one situation where having three boundaries is good: Say one of the official is really good, responsive to needs, pushes for street upgrades, spends their discretionary funds in ways that you like, and attracts more businesses to locate there.

The next door official, however, isn’t as responsive or “good”, but they want those businesses to locate on their side of the street. They’ll become better, in essence, competing.

I don’t think this happens in Chicago, because you’ll tend to have officials who are about the same.

The depicted project was proposed a little over four years ago, and is now complete, it appears.

This map shows how transit access from Uptown would diminish if the Red Line wasn’t there

The dark pink shows areas you can get to within 45 minutes by transit, and the light pink shows you how far you can get within 60 minutes of transit. The transit shed without the Red Line is much smaller!

I virtually dismantled the Red Line to show how important it is to get around the North Side via transit.

Mapzen, a fantastic company that makes free and open source mapping tools, and for whom I’m an independent contractor, updated its Mobility Explorer map to show where you can go from any point in a city by transit if a piece of existing transit infrastructure didn’t exist.

So, I handily took out the Red Line – the Chicago workhorse, carrying 145,000 people each weekday north of State/Lake station. The map shows the analysis, called an isochrone, as if you were departing from the Wilson station in Uptown.

Try it yourself.

You can download the map as a GeoJSON, open it in QGIS, and measure the area in square miles that each scenario covers.

At least 2.5 percent of the land area in Chicago is covered in parking lots and garages

Here’s how I know that at least 2.5 percent of the land area in Chicago is covered in parking lots and garages, as of February 5, 2017.

That’s a lot of polluted water runoff.

I grabbed the land area of 227.3 from the Wikipedia page.

I grabbed all the parking lots from OpenStreetMap via Metro Extracts, which is going to be the most complete map of parking lots and garages.

Volunteer mappers, including me, drew these by tracing satellite imagery.

With the parking lots data in GIS, I can count their area in square feet, which comes out to 160,075,942.42. Convert that to square miles and you get 5.74.

5.74/227.3*100 = 2.5 percent

The last snapshot of parking lot data I have is from February 2016, when only 3.39 square miles of parking lots have been drawn.

There are still many more parking lots to be drawn!

Bicyclists in Chicago can travel pretty far in 15 minutes

Mapzen* released Mobility Explorer last week. It is the graphical user interface (GUI) to the Transitland datastore of a lot of the world’s transit schedules and maps.

It also has isochrones, which are more commonly known as “mode sheds”, or the area that you can reach by a specific mode in a specific amount of time.

I wanted to test it quickly to see what these mode sheds say about where I live, a block north of Humboldt Park. From my house, on a bicycle, I can reach the edges of an area that’s 25 square miles in 15 minutes.

Isochrones map of transportation distance from my house

The distance you can travel from my house at the north end of Humboldt Park in 15 minutes by three modes, assuming you leave at 2:21 PM today (in increasing distance/area): Transit (dark purple) Bicycling (burgundy) Driving (pink)

You can request these isochrones through this API call for any location and they’ll be returned as GeoJSON.

I’m still learning how isochrones work, and how they can be adjusted (to account for different rider seeds and route costs or penalties). One difference between bicycling and driving is that the driving area is increased by expressways while the bicycling area has a more uniform shape.

The bike shed is 25.7 square miles, and the driving shed is 52.0 square miles.

*I do contract work for Mapzen and maintain parts of the Transitland Feed Registry.

Big Marsh Bike Park is the coolest new city park

Big Marsh Bike Park opening day from Steven Vance on Vimeo.

Rahm Emanuel has opened a lot of cool new parks – Maggie Daley, Northerly Island, 606, and Grant Park Skate Park – since he became mayor. (Making arguments that the parking lot south of Soldier Field can’t be anything but a parking lot pretty lame.)

This morning Emanuel cut the ribbon on the Big Marsh Bike Park, first announced in July 2014. It’s still known as Park 564, until the Chicago Park District board adopts a new name.

It’s located at 11599 S. Stony Island Ave. in the South Deering community area in an area already known as Big Marsh. I mapped the park into OpenStreetMap based on a map from the architect, Hitchcock Design Group*.

I've traced an architect's map of the park into OpenStreetMap.

I’ve traced an architect’s map of the park into OpenStreetMap.

The single-track trails, terrain park, and pump track, are free and open to the public every day from dawn until dusk. It resembles the Valmont Bike Park in Boulder Colorado, which I visited in 2014.

Big Marsh was listed in the city’s Habitat Directory in 2005, noting, “Big Marsh is the largest individual wetland in the Calumet Open Space Reserve with approximately 90 acres of open water. Hiking and biking trails and canoe launch are ideas for this area in the future. As of this writing, the site is undeveloped.”

A map of the Big Marsh wetland in 2005 in the City of Chicago's Habitat Directory.

A map of the Big Marsh wetland in 2005 in the City of Chicago’s Habitat Directory. The bike park is mainly in the cleared space east of the #2 on the map.

The area is also part of the the State of Illinois’s Millennium Reserve program, a group of projects to restore natural areas, create new economic development opportunities in the area, and build more recreational sites.

There is no bike infrastructure to access the site, and many roads leading to the site are in bad condition, or have high-speed car traffic. There is a large car parking lot at the site.

* If you would like to help me map the bike park into OpenStreetMap, you can load the architect’s map of the site into JOSM using this WMS tile layer.

Panorama of the bike park, and the landfill to its south

A rider on the terrain park small trail

Oh, how Chicago land use is controlled by spot zoning

If you only had a zoning map to try and understand how the different blocks in the City of Chicago relate to their neighborhoods and the city at large, you might have the idea that the city has no neighborhoods, but is actually a collection of tiny, randomly dispersed zones of differing land uses.

And then when you walked those areas you’d find that the zones, which attempt to prescribe a land use, at least nominally, don’t have anything to do with the restaurant, housing, and commercial building mix of uses actually present.

No plan would have been devised to create a map like this.

Over the last five years, and surely over the last 14, the City of Chicago has been divided (really, split) into an increasing number of distinct zoning districts.

The city’s zoning map is updated after each monthly city council meeting, to reflect the numerous changes that the 50 alders have approved individually. (Their collective approval occurs unanimously in an omnibus bill.)

Every few months I ask the Chicago Department of Innovation and Technology (DoIT) for the latest zoning map, in the form of a shapefile (a kind of file that holds geographic information that can be analyzed by many computer programs). While Chicago has one of the country’s best open data offerings, some datasets, like zoning, don’t get updated in the catalog.

There are two ways I can analyze and present the data about the quantity of zoning districts. Both, however, show that the number of distinct zoning districts has increased. This means that the city is divided even more finely than it was just six months ago.

Analysis 1: Period snapshots

I have the zoning shapefile for five periods, snapshots of the city’s zoning map at that time. From August 2012 to now, May 2016, the number of discrete zoning districts (the sum of all B3-5, RS-1, DX-7, etc. zoning classes) has increased 7.8 percent.

Period Zoning districts change

August 2012

11,278

September 2014

11,677

3.42%

June 2015

11,918

2.02%

November 2015

12,015

0.81%

May 2016

12,162

1.21%

I collect the period snapshots to show the history of zoning at a specific address or building in Chicago, which is listed on Chicago Cityscape. For example, the zoning for the site of the new mixed-use development in Bucktown that includes a reconstructed Aldi has changed four times in four years.

aldi zoning history

Analysis 2: Creation date

The zoning shapefiles also have the date at which a zoning district was split or combined to create a new district, either with a different zoning class (RT-4, C1-1, etc.) or a different shape.

With the most recent zoning shapefile I can tell how many new zoning districts were split or combined and a record representing it was added to the list. The records start in 2002, and by the end of the year 7,717 records were created.

The following year, only 14 records were added, and in 2004, only 6. The Chicago City Council adopted a rewritten zoning code in 2004, and I guess that the zoning map was modified prior to adoption. After 2004, the number of new zoning districts picks up:

year zoning districts added by splitting/combining cumulative change

2002

7717

7717

2003

14

7731

0.18%

2004

6

7737

0.08%

2005

267

8004

3.45%

2006

497

8501

6.21%

2007

561

9062

6.60%

2008

592

9654

6.53%

2009

304

9958

3.15%

2010

245

10203

2.46%

2011

271

10474

2.66%

2012

277

10751

2.64%

2013

299

11050

2.78%

2014

397

11447

3.59%

2015

367

11814

3.21%

2016

173

11987

1.46%

none listed

175

12,162

It seems there’s a light relationship between the recession that started in 2008 and the number of zoning changes made. There are more made annually before the recession than after it. It actually seems to track with building permits (sorry, no chart handy).

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