GIS Class Session Guide: 28 FEB 2017
- Develop a knowledge of the US census data gathering process and the core areas of data explored in the Census.
- Each student will identify a topical and geospatial area of personal inquiry that is relevant in his/her lives on which to build a semester project
- Implement the multi-step process for retrieving and gathering US Census data from TIGER files and Factfinder concerning the area of inquiry of interest to each student
Resources (Same as 21 FEB)
- Kurland and Gorr, Chapter 4: File Geodatabases
- Kurland and Gorr, Chapter 5-6 (Downloading US Census Bureau Boundary Maps), 5-7 (Processing US Census Data), and 5-8 (Downloading ACS data)
Warm-up: Finish our group exercise of downloading US census data for Pittsburgh, PA.
We ended last class with a mini-project of downloading US census TIGER shapefiles and American Community Survey data. Please take the final steps of joining the tables together and conducting a simple choropleth visualization of that data. Scroll down to exercise 3 for a more step-by-step sequence for doing this. Also refer to the Kurland and Gorr chapters referenced above.
When you're done, please export the map as a JPEG image file and email it to Eric at email@example.com with the subject line: US Census in-class activity map
Exercise 1: Exploring US Census data visualizations
The US Census bureau has amassed and released the most comprehensive dataset concerning population and social dynamics of any repository in the USA. There are many visualizations of this data which transform the raw tables from the Bureau into exploration tools that can help users learn more about the country or a specific sub-region of the country. This exercise will ask you to choose two visualizations of US Census data, one being a map and the other a non-map diagram, and compare their value, and investigate their source.
Please follow these steps as a group:
- Navigate to the US Census Bureau's data visualization repository and in another tab open the Census's infographic library and take a moment to glance through the many visualizations folks have made. Note that some are static maps and others are intereactive diagrams, charts, and games that use census data.
- With your partner, choose a general topic of interest by scanning the titles of the various graphs, maps, and infographics. Population growth, for example. Find two items that relate to this topic and study them carefully. What story can you infer from a first glance at the visualization? Where is your eye drawn first in each?
- Now dig in a little more: read the source notes for each graphic? Are they drawing from the same source? Click through any links to data sets and check their format: are they spatially attached data? Is the data current? Who made the graphic?
- Compare the two graphics--which was more effective at conveying information clearly? How did it do so? How would you change the less effective visualization?
- Brainstorm 2-3 questions you'd like to investigate further based on what you learned in the graphics. These should be questions that you think Census data could shed light on. Example: "I see in the circular graphic about where college graduates from various majors end up working--What are the regional patterns behind this data? Are STEM majors from the NE more likely to get STEM Jobs due to proximity to tech company headquarters?"
- Prepare to share your graphics with the group and discuss your questions and findings. Add your links and findings to this GOOGLE DOC which we can use to look at the findings on the class screen.
Exercise 2: Choosing a semester project starting point
Mapping skills come alive when we can practice them applied to an area of interest in your lives and educations. For this course, You'll be preparing a final project that involves a significant data gathering, cleaning, and manipulation effort. Additionally, you'll apply the analytical tools we have yet to learn about to your data and derive some conclusions and future research questions. We'll publish these on the www and you can use the final product as evidence of your map learning for future endeavors.
Projects iterate, meaning they start at a point, move to a new point, and sometimes loop back, while advancing at other times. We should embrace this part of the research process. It is rare that careful work is ever wasted, even if we can't see how it contributes to a final project. To this end, tonight, you'll decide on a starting point for a final project by choosing a geographic region of interest and a few broad inquiry questions related to this area. Your project will not revolve around census data but rather will use the census data to contextualize the dataset from another source you'll work on finding. To get started, answer these questions for yourself in an email to Eric. You may want to write these in your own word processing doc or google doc so you can build on it later.
- Choose a region of the country you have an interest in learning more about. This certainly could be our local area in Allegheny County. Your region should probably be a county or smaller. You are discouraged from choosing state or national level areas because the level of analysis required to make conclusions about such a large area are outside the scope of this course.
- Spend about 15 minutes reading resources within a few different topic areas featured on the US Census topics page. Each topic has 5-10 subtopics, and each has a number of data sets, papers, and visualizations to support it. This can be overwhelming, but take deep breaths. Don't lock yourself in too soon. Make a list of the top three topics and subtopics that contain data that you are interested in exploring for your region. List these in your email blurb.
- Review your list and choose one of your three choices to investigate more closely. Brainstorm 2-3 inquiry questions with respect to this topic and subtopic. Don't be afraid to add some justifications for that inquiry question to prompt your thinking.
- Finally, brainstorm some outside data sources that might be held by another agency or organization that you'd like to get your hands on to conduct this research. For example, perhaps you're interested in water quality issues related to fracking. You'd probably want to find a data set concerning well locations and water quality violations from an agency, such as the State of PA's department of Environmental Protection.
Exercise 3: Start your project with the US Census data
Even though we're just now starting into brainstorming for our final projects, we'll use your project ideas to start a practice session on gathering Census Shapefiles and ACS data, cleaning it, importing it, and keeping your life organized. We'll focus on a few core research skills that will help us down the line. As you do this exercise, please follow these guidelines:
- Start your project by creating a new directory in any location besides your desktop (desktops have strange file access restrictions). Name it something logical and don't use any spaces or funny characters.
- Inside ArcCatalog, create a new fileGeodatabase with a logical name, perhaps the same as the directory you just created. Locate the geodatabase in your project directory.
- Create a directory in your project directory called "rawData" where you'll download any data sets to before cleaning them.
- Create a word processing document called "processLog***" and replace the *** with a reference to your project and your name. In that document, start a list of the steps you take as you conduct your project. This is for YOU to reference as you go back to your work this term, or after this term. Be as detailed as you need to replicate your thinking, assuming you forget any project-specific information. Include links to data sources. Include tricky software steps taken. Make notes about questions or odd things that you'll forget later. Include data and times with each entry. (Times matter!)
With these steps in mind, please complete the following steps with respect to your initial project area of interest. These steps are non-exhaustive. Please refer to the Kurland and Gorr text if you need specific "click here, then click here" kinds of steps.
- Download the TIGER Shapefiles for the area of interest. Choose census Tract as your geography. It also wouldn't hurt to get the blocks and block groups since we can use those for census count data that isn't subject to the margins of error that the ACS sampling is. Save these shapefiles in your raw data directory.
- Import the shapefiles you've downloaded into your file geodatabase and load them into a new map. Save that new map with a logical name in your project directory. Remember data is saved inside the geodatabase, and project files outside the geodatabase but in your project directory.
- Navigate to American factfinder and locate 1-2 American Community Survey tables that contain data relevant to your topic. Download these tables and open them in a spreadsheet program. Make a backup copy of these. Perhaps in a directory called "backup" within your rawData directory?
- Open the meta-data file for your ACS tables which lists the field descriptions for each of the table columns. Use highlighting to select primary fields of interest, and secondary fields. Make note of the fields you might want for context, such as total population counts. Include margin of error columns along with your "estimate" columns.
- In your spreadsheet with the actual data, delete all extraneous columns based on your meta data search. Export this table as a .csv file. Import this table into your file geodatabase using import>rows from table inside arc catalog
- Add the imported table into your map project. Check for the proper ID columns in the TIGEr shapefile and your ACS table. Covert both to a 'double' data type by creating a new field in any table in which the ID is not a double type, and choose 'double' as the data type. (i.e. create a new field with a type: double) Then use "calculate field" to copy over the value of the table key into that column with a data type 'double.'
- With the join columns in the same data type, conduct your join by accessing the properties menu on your TIGER shapefile layer, selecting "Joins and relates" tab and add a join. Follow the prompts carefully. Check your TIGER table to make sure the join worked.
- Conduct a simple visualization of the data you just imported. Tinker a bit and see what insights you can glean into your inquiry questions from earlier. Prepare to share your findings with the class next week including an image export of your preliminary map