Tag: GIS

Bike crash map in the press

February 21, 2011 / / 0 Comments

Thank you to the Bay Citizen, Gapers Block, and the Chicago Bicycle Advocate (lawyer Brendan Kevenides). They’ve all written about the bike crash map I produced using Google Fusion Tables. And WGN 720 AM interviewed me and aired it in April 2011.

View the map now. The map needs to be updated with injury severity, a field I mistakenly removed before uploading the data.

The Bay Citizen started this by creating their own map of bike crashes for San Francisco, albeit with more information. I had helped some UIC students obtain the data from the Illinois Department of Transportation for their GIS project and have a copy of it myself. I quickly edited it using uDig and threw it up online in an instant map created by Fusion Tables.

A guy rides his bicycle on the “hipster highway” (aka Milwaukee Avenue), the street with the most crashes, but also has the most people biking (in mode share and pure quantity).

Why did I make the map?

I made this project for two reasons: One is to continue practicing my GIS skills and to learn new software and new web applications. The second reason was to put the data out there. There’s a growing trend for governments to open up their databases, and your readers have probably seen DataSF.org’s App Showcase. But in Chicago, we’re not seeing this trend. Instead of data, we get a list of FOIA requests, or instead of searchable City Council meeting minutes, we get PDFs that link to other PDFs that you must first select from drop down boxes. But both of these are improvements from before.

I would love to help anyone else passionate about bicycling in Chicago to find ways to use this data or project to address problems. I think bicycling in Chicago is good for many people, but we can make it better and for more people.

Read the full interview.

Trying out uDig, a free, multi-platform GIS application

February 10, 2011 / / 0 Comments

ArcGIS is the standard in geographic information system applications. I don’t like that it’s expensive, unwieldy to install and update, and its user interface is stymying and slow*. I also use Mac OS X most of the time and ArcGIS is not available for Mac. It doesn’t have to be the standard.

I’ve tried my hand at Cartographica and QGIS. I really like QGIS because there’re many plugins, it’s open source, there’s a diverse community supporting it, and best of all, it’s free. I’ve written about Cartographica once – I’m not a fan right now.

My project

  • The data: Bicycle crashes in the City of Chicago as reported to IDOT for 2007-2009
  • Goal: Publish an interactive map of this data using Google Fusion Tables and its instant mapping feature.
  • Visualizing it: Added streets (prepared beforehand to exclude highways), water features, and city boundary (get that here)
  • Process: Combine bike crash data; reproject to WGS84 for Google; remove extraneous information; add latitude/longitude coordinates; export as CSV; upload to Google Fusion Tables; map it!
  • View the final product

Trying out uDig

In reaching my goal I had a task that I couldn’t figure out how to complete with QGIS: I needed to combine three shapefiles with identical table schemes into one shapefile – this one shapefile would eventually be published as one map. The join feature in fTools wasn’t working so I looked for a new solution, uDig, or “User-friendly Desktop Internet GIS.”

The solution was very easy. Highlight all the records in the attribute table of one shapefile, click Edit>Copy, then select the destination table and click Edit>Paste. The new records were added within a couple seconds. I could then bring this data back into QGIS to finish the process (outlined above under Project). I did use fTools later in the process to add lat/long coordinates to my single shapefile.

After adding more data to better visualize the crashes in Chicago, I noticed that uDig renders maps to look smoother and slightly prettier than QGIS or ArcGIS. See the screenshot below.

A screenshot of the three bicycle crash datasets (2007, 2008, 2009) with the visualization data added.

The end product: three years of police reported bicycle crashes in the City of Chicago on an interactive map powered by Google Fusion Tables, another product in Google’s arsenal of GIS for the poor man. View the final product.

*I haven’t used ArcGIS version 10 yet, which I see and read has an improved user interface; it’s unclear to me and other users if the program’s been updated to take advantage of multi-core processors. ESRI has a roundabout way of describing their support.

I want to make a crash reporting tool

November 30, 2010 / / 0 Comments

UPDATE 12-01-10: Thank you to Richard Masoner for posting this on Cyclelicious. I have started collecting everyone’s great ideas and responses in this development document.

Hot off the heels of making my “Can I bring my bike on Metra right now?” web application, I am ready to start on the next great tool*.

I want to create a bicycle crash reporting tool for Chicago (but release the source code for any city’s residents to adopt) along the lines of B-SMaRT for Portlanders and the Boston Cyclist’s Union crash map based on 911 calls.

I’d rather not reinvent the wheel (but I’m very capable of building a new web application based in PHP and MySQL) so I’ve been trying to get in contact with Joe Broach, the creator of B-SMaRT, to get my hands on that source code.

Not exactly the type of crash I’ll be looking for. Photo by Jason Reed.

I want the Chicago Crash Collector (please think of a better name) to have both citizen-reported data, and data from police reports. I just sent in my FOIA request for police data to the Chicago Police Department, but I’m not holding my breath for that.

3D experimentation to improve pedestrian environment

October 28, 2010 / / 0 Comments

3D experimentation to improve pedestrian environment from Steven Vance on Vimeo.

The movies aren’t the only place where you’ll see in 3D! Go check out Clark and Deming (about 2540 N Clark Street) in the Lincoln Park neighborhood to see a special pedestrian safety marking on the pavement. They were installed on October 18, 2010.

Designed to increase nighttime visibility

Who’s involved?

  • Chicago Department of Transportation (CDOT)
  • National Highway Traffic Safety Administration (NHTSA)
  • Western Michigan University (WMU)

All three entities are involved in the installation of these optical illusion zig-zag markings.

Between and including years 2005 and 2009, there were at least 2 reports of injuries to people walking and at least 9 reports of collisions involving people riding bikes*. With that data in mind, I’m not sure why this location was selected for a pavement marking whose aim is to improve pedestrian safety. The data do indicate that this intersection has a lot of bicycle-related collisions, much more than I’m seeing for other intersections.

Clark and Deming

Curiously, there are no automobile traffic counts for miles in either direction on Clark Street so one cannot compare the number of collisions at the Clark and Deming intersection with other intersections in town. Out of over 1,200 count locations, Clark Street in Lincoln Park was skipped.

Not really stopping for pedestrians

*Data from the Illinois Department of Transportation Safety Data Mart (which was taken down in 2015 or 2016)

Obtaining Chicago Transit Authority geodata

October 12, 2010 / / 0 Comments

A reader asked where they could get Chicago Transit Authority (CTA) data I didn’t already have on the “Find GIS data” page. I only had shapefiles for train lines and stations. Now I’ve got bus routes and stops.

You can download General Transit Feed Specification (GTFS) data from the CTA’s Developer Center. It’s updated regularly when service changes.

Screenshot from ESRI ArcMap showing the unedited shapes.txt file loaded via Tools>Add XY Data. Shapes.txt is an 18 MB comma-delimited text file with thousands of points that can be grouped together with their shape_id.

The GTFS has major benefits over providing shapefiles to the public.

  1. It can be easily converted to the common shapefile format, or KML format.
  2. Google, the inventor of GTFS, has defined and documented it well; it is unencoded and plaintext. These attributes make it easy for programmers and hackers to manipulate it in many ways. (see also item 4)
  3. Google provides a service to the public on its website, an easy to use and robust transit planning service.
  4. The data is stored as plaintext CSV files.
  5. While an agency like CTA may have a geodata server on its intranet, it is less likely it has the addons that provide mapping and geodata services for the internet. A server like Web Mapping Service, or ArcIMS. These systems can be expensive to purchase and license. And we all know how the CTA seems to always be in a money crunch. While the CTA updates its GTFS data for publishing to Google Maps, the public can download it simultaneously to always have up-to-date information, providing the same geodata that ArcIMS or WMS would offer but for no additional cost.

I couldn’t have pulled off this conversion in 24 hours without the help of Steven Romalewski’s blog, Spatiality. He pointed me to the right ArcMap plugin in this post about converting the Metropolitan Transportation Authority’s GTFS data into shapefiles. I hope Steven doesn’t move to Chicago less my authority on GIS and transit be placed in check!

Make your own map of the CTA train routes and perform some kind of analysis – then share it with the rest of us!

Read more about my exercise in geodata conversion in the full post.
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