Category: Information

How to split a bike lane in two and copy features with QGIS

July 13, 2012 / / 0 Comments

A screenshot of the splash image seen on users with iPad retina displays in landscape mode. 

To make the Chicago Offline Bike Map, I need bikeways data. I got this from the City of Chicago’s data portal, in GIS shapefile format. It has a good attribute table listing the name of the street the bikeway is on and the bikeway’s class (see below). After several bike lanes had been installed, I asked the City’s data portal operators for an updated shapefile. I got it a month later and found that it wasn’t up-to-date. I probably could have received a shapefile with the current bikeway installations marked, but I didn’t have time to wait: every day delayed was one more day I couldn’t promote my app; I make 70 cents per sale.

Since the bikeway lines were already there, I could simply reclassify the sections that had been changed to an upgraded form of bikeway (for example, Wabash Avenue went from a door zone-style bike lane to a buffered bike lane in 2011). I tried to do this but ran into trouble when the line segment was longer than the bikeway segment that needed to be reclassified (for example, Elston Avenue has varying classifications from Milwaukee Avenue to North Avenue that didn’t match the line segments for that street). I had to divide the bikeway into shorter segments and reclassify them individually.

Enter the Split Features tool. QGIS is short on documentation and I had trouble using this feature. I eventually found the trick after a search that took more time than I expected. Here’s how to cut a line:

  1. Select the line using one of the selection tools. I prefer the default one, Select Features, where you have to click on the feature one-by-one. (It’s not required that you select the line, but doing so will ensure you only cut the selected line. If you don’t select the line, you can cut many lines in one go.)
  2. Toggle editing on the layer that contains the line you want to cut.
  3. Click Edit>Split Features to activate that tool, or find its icon in one the toolbars (which may or may not be shown).
  4. Click once near where you want to split the line.
  5. Move the cursor across the line you want to split, in the desired split location.
  6. When the red line indicating your split is where you desire, press the right-click mouse button.

Your line segment has now been split. A new entry has been added to the attribute table. There are now two entries with duplicate attributes representing that together make up the original line segment, before you split it.

This screenshot shows a red line across a road. The red line indicates where the road will be split. Press the right-click mouse button to tell QGIS to “split now”.

After splitting, open the attribute table to see that you now have two features with identical attributes. 

Copying features in QGIS

A second issue I had when creating new bikeways data was when a bikeway didn’t exist and I couldn’t reclassify it. This was the case on Franklin Boulevard: no bikeway had ever been installed there. I solved this problem by copying the relevant street segments from the Transportation (roads) shapefile and pasted them into the bikeways shapefile. New entries were created in the attribute table but with blank attributes. It was simple to fill in the street name, class, and extents.

Chicago bikeways GIS description

Bikeway classes (TYPE in the dataset) in the City of Chicago data portal are:

  1. Existing bike lane
  2. Existing marked shared lane
  3. Proposed on-street bikeway
  4. Recommended bike route
  5. Existing trail
  6. Proposed off-street trail
  7. Access path (to existing trail)
  8. Existing cycle track (also known as protected bike lane)
  9. Existing buffered bike lane

It remains to be seen if the City will identify the “enhanced marked shared lane” on Wells Street between Wacker Drive and Van Buren street differently than “existing marked shared lane” in the data.

My Chicago Card Plus tells me how often I use the CTA

July 9, 2012 / / 0 Comments

In this interview with Chicago Transit Authority president Forrest Claypool, I admitted to him and everyone else in the room (three bloggers and three CTA staff) that I rarely ride the CTA. The purpose of my admission was to explain how I gathered up so many questions. A lot of them come from friends and Grid Chicago readers. I always use my Chicago Card Plus to pay for fares because it’s extremely convenient: I never have to worry about having the correct fare and it can be replaced for a nominal $5 fee, protecting your money (the Chicago Card doesn’t have the same benefit because it can’t be registered). Anyway, it also tracks you and you can look up your history. I looked at it to understand just how rarely I use the CTA.

The Chicago Card Plus website shows your data in two ways: the last 5 transactions, and the last 90 days. It turns out that the last 5 transactions were beyond the 90 day period.

  • June 29, train (Blue Line)
  • May 22, bus (56/Milwaukee)
  • March 31, bus (I don’t remember which, but probably the Belmont bus with my mom)
  • March 31, bus

The fifth transaction was loading the card with more money. I think there was one other bus use on March 31, because the most recent two showed as transfer transactions. So I’ve added one more to the list.

  • March 31, bus

Five uses in 98 days, or 1 ride per 19.6 days.

Brief history of suburbs and sprawl, according to Taras Grescoe’s “Straphanger”

June 29, 2012 / / 0 Comments

The Metra station in Riverside, Illinois, a version 1.0 streetcar suburb designed by Frederick Law Olmsted and Calvert Vaux. 

I’m reading another book a publisher sent to me. It seems pretty biased, and it’s biased in the direction I already feel, so it’s really easy reading. But it seems that people like me are its only audience and that it assumes I’m already pro-cities, anti-suburbs and maybe even anti-car. Definitely not a book that’s going to espouse the benefits of transit to those who don’t use it, don’t want to use it, or are on the fence for either situation.

If I could get my father or brother to read this book, that would be an accomplishment just short of a miracle.

The book is Straphanger: Saving our cities and ourselves from the automobile, by Taras Grescoe. I really like the section I just finished reading, a “condensed history of sprawl”. I had recently “argued” with my father about the development of the subdivision he lives in, east of Phoenix. He posited that suburbs were the result of consumer desires. Grescoe writes to the contrary. Here we go:

The origin of the Anglo-American suburb has been traced to Clapham, five miles south of London, where, in the 1790s, Evangelical Christians eager to remove their families from the evils of the city began living in what had formerly been their weekend villas, and commuting to the City by private carriage. In the United States, [author Kenneth] Jackson dates the beginning of the process to 1815, when regular steam ferry service to Manhattan made Brooklyn Heights the nation’s first true commuter suburb. (page 89)

American suburb version 1.0

  • When: 1853 onward
  • What it was: picturesque, full of green space, near central cities, attached by rail line
  • Who lived there: As mortgages didn’t exist, only those who could afford to buy a home outright
  • Examples: Llewellyn Park, NJ; Riverside, IL.
  • Note: Ebenezer Howard’s “Garden City” design is related.

American suburb version 2.0

  • When: Post World War II
  • What it was: cheap, small housing on vast land tracts; pre-assembled homes
  • Who lived there: Families with soldiers that expanded quickly so new homes were needed fast.
  • Examples: Levittown, Long Island; Lakewood, Los Angeles.
  • Note: “The prevailing myth”, writes Kenneth Jackson, “is that the postwar suburbs blossomed because of the preference of consumers who made free choices in an open environment. Actually, most postwar families were not free to choose among several residential alternatives. Because of public policies favoring the suburbs, only one possibility was economically feasible”.

American suburb version 3.0

  • When: Late 1980s, 1990s to now
  • What it was: Found near office parks, also known as “edge cities”, “common interest communities” (gated and homeowners associations)
  • Who lived there: Single races (self-segregating), people who lean conservative
  • Examples: Silicon Valley, Nevada, Florida
  • Note: Under the George W. Bush administration, Fannie Mae and Freddie Mac offered easy credit and homeownership rate rose to 69% by 2004. “(By 2012, it is expected to drop to 62%, the lowest level since 1960.)”

American suburb version 4.0

  • When: 2008, easy credit crisis, underwater mortgages
  • What it is: Least glamorous, the clichéd image of the inner city has moved to the suburbs. Arizona has highest rate of property crime. Nevada and Florida, the most suburbanized states, have highest rates of violent crime (Florida also has highest rate of pedestrian and bicycle fatalities).
  • Who lives there: A diverse group of people.
  • Examples: See “What it is”
  • Note: “Humans are social animals. I [Kenneth Jackson] think the biggest fake ever perpetrated is that children like, and need, big yards. What children like are other children. I think we move children to the suburbs to control the children, not to respond to something the children want. In the city, the kids might see somebody urinate in public, but they’re much more at risk in the suburbs, where they tend to die in cars.”

What are those public policies as described in American suburb version 2.0?

The federal government had carrots and sticks. Carrots were subsidies for homeownership (could be deducted from income taxes) and no down payment required for returning soldiers. Sticks included redlining (racial segregation), propagated by the Federal Housing Administration and banks. Zoning was another stick, which dictated what could go where.

Another carrot was the federally-funded highway system, the “greatest public subside to private real estate in the history of the world”.

Finding data about traffic and roads in Illinois

June 16, 2012 / / 0 Comments

There are two good websites that provide information about roads, traffic, and their many attributes. One is provided by the Illinois Department of Transportation (IDOT) called Getting Around Illinois (GAI). The second is the Traffic Count Database System (TCDS).

Both provide Average Daily Traffic (ADT) counts with TCDS making the information easier to find and presents more of it.

The GAI map has an important layer: jurisdiction. With that information you can determine who has “ownership” of a road. Jurisdiction has been an important factor in the nearly year-long delay of the Jackson Boulevard protected bike lane segment from Ogden Avenue to Halsted Street. IDOT has jurisdiction over this segment (which continues east to Lake Shore Drive; the road is also known as Route 66) and is requiring that the Chicago Department of Transportation do more analysis and revise their designs.

If you are looking for ADT counts, I highly recommend TCDS as it uses the more familiar Google Maps and doesn’t require the Microsoft Silverlight plugin (which is slow and often denigrated with poor usability applications).

GAI has truck routes and crash information as well.

The Green Lane project is announced in Chicago

June 7, 2012 / / 0 Comments

I covered this event for a Streetsblog article (which has been delayed). Essentially the Bikes Belong Foundation and its donors are trying to get “better bike lanes” (Euro-style) installed faster across North America. It’s more of a strategic planning thing; the money isn’t going to be used for paying for construction of the bike lanes.

It’s about knowledge sharing and technical assistance and documenting the process. Eventually this knowledge will be shared with all cities in the whole country. But essentially, Austin, Texas, can use this network to be able to get some help from Chicago or San Francisco, without incurring on those cities’ ability to quickly get their own lanes in.

See all photos from the soirée and then the next day’s press conference (Wednesday, May 30, and Thursday, May 31).

I am somewhat impressed that the director of the Federal Highway Administration*, Victor Mendez, pictured above, came from Washington, D.C., to tell us about the federal government’s support for bike lanes. I wish he could have said the same thing about House Republicans’ support. They’re against transit, too. I asked Victor to tell transportation secretary Ray LaHood to read Grid Chicago.

Watch this video by Nick Brazinsky. I believe he was hired by Bikes Belong to shoot it. That he roller skates to take video makes the film a little cooler.

The Green Lane cities are:

  • Chicago, Illinois
  • Austin, Texas
  • Washington, D.C.
  • Portland, Oregon
  • San Francisco, California
  • Memphis, Tennessee (this one’s inclusion is exciting)

* The FHWA administers bike lane funding, as well as funding for roads and highways. They are in charge of the CMAQ, Congestion Mitigation and Air Quality, funding program.