Tag: counting

Free online GIS tools: An introduction to GeoCommons

Read my tutorial on how I created the pedestrian map with GeoCommons. Read on for an introduction to GeoCommons and online GIS tools.

GeoCommons, like Google My Maps and Earth, is part of the “poor man’s GIS package.” It’s another tool that provides (few) of the functions that desktop GIS software offers. But it excels at making simple and somewhat complex maps.

I first used GeoCommons over a year ago. I started using it because it would convert whatever data you uploaded into another format that was probably more useful. I mentioned it in this article about converting files. For example, if you have a KML file, you can upload it and export it as a shapefile for GIS programs, or a CSV file to load into a table editor or spreadsheet application.

After creating the Chicago bike crash maps using Google Fusion Tables, I wanted to try out another map-making web application, one that provided more customization and prettier maps.

I found that web application and created a version of the bike crash maps, with several other data layers, in GeoCommons. I overlaid bike counts and bikeways so you can observe some relationships between each visual dataset. My latest map (screenshot below), created Wednesday, shows pedestrian counts in downtown Chicago overlaid with CTA and downtown Metra stations, as well as the 48 intersections with the most pedestrian collisions (from this UNC study, PDF).

Screenshot of pedestrian count map described above.

How these online GIS tools can be useful to you

I bet there’s a way you can use Google Fusion Tables and GeoCommons for your job or project. They’re extremely simple to use: they can take in data from the spreadsheets you’re already working on and turn them into themed reference maps. With mapping, you can do simple, visual analysis that doesn’t require statistical software or knowledge.

Imagine plotting your client list on a map and grouping them by age to see if perhaps your younger clients tend to live in the same neighborhoods of town, or if they’re more diverse (should you do this, keep the map private, something that you can’t do in GeoCommons – yet).

You may also find it useful if you want to create a route for your salespeople or for visiting church members at their homes. Plot all the addresses on a map, then manually filter them into different groups based on the clusters you see. With Google Fusion Tables, you can easily add a new column with the GROUP information and apply a numbered or lettered group and then re-sort.

Other things you can do in GeoCommons

  • Merge tables with geography – I uploaded two datasets: a table containing census tract IDs and demographic information for Cook County I downloaded from the American FactFinder 2; and a shapefile containing Cook County census tracts boundary information. After merging them, I could download a NEW shapefile that contained both datasets.
  • Make multi-layer maps
  • Symbolize based on frequency/rate
  • Convert data – This is by far the most useful feature. It imports “shapefiles (SHP), comma separated values (CSV), Keyhole Markup Language (KML), and GeoRSS” and exports “Shapefile, CSV, KML, GeoRSS Atom, Spatialite, and JSON” (from the GeoCommons user manual).

Read my tutorial on how I created the pedestrian map with GeoCommons.

You asked for it, you got it – Chicago bike count data

Note: This post doesn’t have any analysis of the data or report, nor do I make any observations. I think it’s more significant to hear the ideas you have about what you see in the map or read in the data.

A lot of people wanted the Chicago bike crash and injury data overlaid with bike counts data.

In 2009, Chicago Department of Transportation (CDOT) placed automatic bike counting equipment at many locations around the city. It uses pneumatic tubes to count the number of bicyclists (excludes cars) at that point in the street – it counts ALL trips, and cannot distinguish between people going to work or going to school. This is dissimilar from Census data which asks respondents to indicate how they go to work.

Well, good news for you! CDOT today released the bike counts report from data collected in 2009 (just in time). There has been overwhelming response about the bike crash map I published – this shows how rabid the public is for information on their environments (just yesterday someone told me that they switched bike routes based on the crash frequency they noticed on their original route).

The size of the blue dot indicates the bicycle mode share for that count location. Mode share calculated by adding bikes and cars and dividing by bikes.

Get the data

A photo of the EcoCounter counting machine in action on Milwaukee Avenue (this was taken during testing phase, where CDOT compared automatic and manual counts to determine the machine’s accuracy).

How to use this map:

  1. Find a blue dot (count location) in an area you’re interested in.
  2. Zoom into that blue dot.
  3. Click on the blue dot to get the number of bikes counted there.
  4. Then observe the number of purple dots (crashes) near that count location.

What do you see that’s interesting?

What else is coming?

Now let’s hope the Active Transportation Alliance and the Chicago Park District release their Lakefront Trail counts from summer 2010. CDOT may have conducted bicycle counts in 2010 as well – I hope we don’t have to wait as long for that data.

I hope to have a tutorial on how to use GeoCommons coming soon. You should bug me about it if I don’t post it within one week.

Photos of Chicago bike commuters by Joshua Koonce.

Why did women in Chicago stop bicycling to work? And other stories about data

Why did women in Chicago stop bicycling to work?
Or is our data unreliable?

Showing relative cycling-to-work rates between 2005 and 2009 in Chicago. Data from table S0801 in American Community Survey, 1-year estimates. Read the comments on this post for why this is not the best data source – 3-year estimate shows same decline in women cycling to work.

Note: The sample size is puny – data was collected from 80,613 housing units in Illinois. I don’t know how many of those were in Chicago (and we have 1,063,047 housing units). The American Community Survey only collects data on transportation modes to work for ages 16 and up.

But we simply have no other data! Maybe the Chicago Metropolitan Agency for Planning can release the Chicago data they collected for the 2008 household travel survey to show us bicycling rates for all trip purposes (they divided the report into counties). The sample size would still be small, but we could compare the work rates to find some support between the datasets.

We should look into how New York City counts bicycling as an additional way to gauge trends in Chicago (it has limitations of geography and area).

They conduct two types of counts. The first is the screenline count for bridges, Staten Island Ferry, the Hudson River Greenway, and all Avenues at 50th Street. They do this three times per year. Then, seven more times a year, they count at the same places (except the Avenues) from April to October.

While this data does not give them information on who cycles in the boroughs, it does give them a good indicator of cycling levels in Manhattan. It also disregards trip purpose, counting everyone going to work, school, or for social activities.

Sidenote: The New York Police Department will begin making monthly statistical reports on bicycle crashes in the city.