Downloading Spatial Data

Now we'll be using our skills gained so far to
  1. download data
  2. unzip it
  3. store it in the data directory of the homepage directory.
There are two different sets of data to collect: data from the Illinois census, and data on influenza in France.
  1. Later on in this course we'll be studying some cancer data for Illinois (by county), so we'd like you to go to this ftp site and pick up census information for the counties. I'm not going to tell you which files: I expect you to figure it out! There are two small zip files in this directory concerning all counties of illinois. Can you find them?

    Once you've identified the zip files you want, you can right click on the links to the files, and you will be given the option to "Save link as". By doing so, you will save the file to your local machine. Alternatively, many browsers are configured to call WinZip automatically when a zip file is encountered (so left-clicking would call up WinZip to unzip your files). You might try both methods.

    You'll need a directory in which to save your files, and for that we have already created the data subdirectory of your epid624 web directory (any directory will do, but this will help us keep track of your data here at UMich).

    If your home page is ready, then unzip the files, and extract the data to your data directory. If the files unzipped properly, then you can delete the zip files. If you now go back to your homepage and click on the data link, you should see the two files safely stored in your directory. Do you? If so, click on one of the files, so that your browser will display it.

    Can you figure out what the variables mean? There is (minimal!) documentation available in the ftp directory on the variables - can you find it? It's not easy!

    Note the mammoth quantity of data available: you could spend weeks just snooping around these census files. It's all on-line, and free (at least it's free for the moment: the government charges for some data and not for other data, based on some mysterious method).

    Alert/plea: don't forget to record your "Meta Data" (data about the data): Where did you get the data (e.g. a web site, from your best friend, etc.)? Who created it? Why? Why did you download it? When? The more of this meta data you can gather and keep with the data, the better. Otherwise, three months from now, you'll claim under oath that you've never seen this data before, and for all you'll remember you may be right.... The easiest way to do this is to create a file in the same directory as the data, containing this sort of information. Do so now using your favorite text editor. Remember, however, that anything you put into this directory can be read by the whole world through their web browsers.

  2. Now it's on to the French Flu Data (download and save this file as flu.txt.gz in your data directory). The data is originally from Sentiweb.

    Take a spin around the Sentiweb site, especially the interactive queries. Notice the weekly reports too. This is a cool surveillance site!

    This data (like the Illinois data) will become a familiar friend throughout our course, because we plan to download the data on a weekly basis. This data will be used in our surveillance unit. You'll be watching the French Flu season unfold before your eyes!

In our next lab we'll start mapping this data, using ArcView.
Website maintained by Andy Long. Comments appreciated.
aelon@sph.umich.edu