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Assignment 4

This week we covered two major features of any GIS that help you modify data: geoprocessing and joining. The purpose of this assignment is to give you some experience with both of these.

Please read the map grading rubric that will be followed for most assignments in this course.

Resources

Updated for QGIS 3:

Not updated for QGIS 3, but should work fine:

Part 1: Geoprocessing

Geoprocessing tools give you the means to overlay multiple vector layers in order to modify the layers and potentially combine them. You are most likely going to find the following geoprocessing functions to be the most useful:

Buffers can be especially useful when talking about proximity, and you'll probably find these useful in the following assignment from your council member:

Hi GIS pro,

The group in our district arguing for safer streets is looking for more detail about motor vehicle collisions for the past year. I was thinking we could either highlight the collisions near schools or bike lanes. I trust you to pick the one you find most illuminating. In addition to highlighting these collisions I'd like to answer these questions:

  • What percentage of the crashes in our district happened near schools or bike lanes (again, your choice)?
  • How many injuries and deaths happened as a result of these crashes?

Thanks for all your help!

Buffer the schools (I'd start with 500 feet) or bike lanes (I'd start with 25 feet) and use Select by Location to find the collisions in those buffers. You're free to re-use the collisions data you downloaded for the previous assignment, in addition to other map elements as they're useful.

Part 2: Joins

When you join two or more datasets, you combine them feature-by-feature, and this often gives attributes to a feature that it would not have otherwise had.

Attribute joins add attributes to features based on a unique identifier. Often you will have a spatial dataset (such as a shapefile) and a CSV file with extra data that you would like to map. As long as both the spatial data and the CSV have a common unique identifier (sometimes this is a name, but it could be a unique number or an address) you can join them in QGIS and add the data from the CSV to the spatial data.

Use attribute joins to help your council member with the following:

Hi again map-maker,

Now that you're getting settled in, we'd like to get a better look at our council district using census data. In particular, let's start with renter occupancy or median household income (your choice) by census tract. Make the focus our district, but please show the surrounding area, too, for context.

Thanks as always!

Download census data using American FactFinder, join with the census tracts, and make a choropleth map with some of the joined data. Choose which data to get:

  1. renter vs owner occupancy
    1. Guided Search
    2. "I'm looking for information about housing"
    3. Occupancy Characteristic > Owner/Renter (Tenure in Occupied Units)
    4. Get census tracts for the county or counties your district is in
    5. At "Are you looking for data for a race or ethnic group (race, ancestry, or tribe)?" you can select Skip this Step
    6. Select "TENURE"
  2. household income
    1. Guided Search
    2. "I'm looking for information about people"
    3. Income & Earnings > Income/Earnings (Households)
    4. Get census tracts for the county or counties your district is in
    5. At "Are you looking for data for a race or ethnic group (race, ancestry, or tribe)?" you can select Skip this Step
    6. Select "MEDIAN INCOME IN THE PAST 12 MONTHS (IN 2016 INFLATION-ADJUSTED DOLLARS) "

For both, you'll want to:

  1. Modify Tables > Transpose Rows / Columns
  2. Download > Use this data
  3. Edit the resulting CSV

Submitting Your Work

Include a PDF or image export for Part 1 and a PDF or image export for Part 2.

Finally, include a short summary (1/2 page) of what you did for this assignment. Explain what you created and how you did so. What did you have problems with? What did you enjoy? What would you like to know how to do next?