GIS I - Lab 2: Downloading GIS Data

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Goal and Objectives

The goal of this lab exercise is to learn how to download and map data from the U.S. Census Bureau. This particular lab will focus on Wisconsin census data.

Objectives:

1. Download 2010 Census data (total population) from the US Census Bureau
2. Download a shapefile of the 2010 Census boundaries from the US Census Bureau
3. Join the downloaded data to the Census shapefile
4. Map the data
5. Download and map a variable of your choice
6. Build a layout with both maps
7. Build a web map with one of the variables

Instructions to recreate each of the objectives completed in this lab can be found in the Methods section of this post.

Methods

This section outlines the steps taken to complete each of the learning Objectives for this lab exercise. These procedures can be used in the future to recreate this lab, or can be used as supplemental material when performing similar tasks in the future.

Objective 1: Download 2010 Census Data from the US Census Bureau

US Census Bureau Fact Finder: Advanced Search Interface

  • Click ‘Advanced Search’ in the top navigation bar. On this page, use the filters on the left side of the page to create a data set that includes all of the data necessary to reach the goals of this geographic inquiry.
  • As selections are made, they are added to the ‘Your Selections’ box above the search filters. For this particular lab, the data being selected includes… Population totals of all Wisconsin counties.
  • Within the results list, find the P1 – ‘TOTAL POPULATION’ Table from the ‘2010 SF1 100% Data’ Dataset and download it (seen in the image below).

  • The data will download as a .CSV file. Open it in Excel and save it as an .XLSX file.

Objective 2: Download the Shapefile for the WI Census Data


In order to find the shapefile for the state of Wisconsin to download, return to the ‘Geographies’ section of the Advanced Search, click the ‘Map’ tab and then click the ‘Download’ icon on the right side of the map.


Objective 3: Join the Data Together

  • Add the Wisconsin shapefile to a blank map
  • Add the Total Population data table (Excel file) that was downloaded from the Census website
  • Open both tables and arrange them side by side to find the common attribute between the two. The common attribute is what will be used to create the Join. In this case, “GEO#id” is the common attribute.
  • Execute the Join by right clicking on the shapefile and selecting Joins and Relates > Joins…
  • In the Join Data dialog, select the common attributes that were determined earlier



Objective 4: Map the Data

  • The population field that was joined to the shapefile does not initially show up in the list of quantity fields to display on the map. This is because it was imported as a ‘string’ field type and therefore cannot be mapped quantitatively.
  • In order to fix this:
    • Open the attributes table of the shapefile and add a new field with the field type of ‘Double’
    • On the new field, right click and open the Field Calculator and select the original string field
    • Map the new field as a quantity

Objective 5: Map Another Variable

This map will display the average home size per county across the state of Wisconsin. 
  • Download the ‘HOUSING UNITS’ table from the US Census Bureau Fact Finder website. 

  • Open the tabular data CSV file and save it as a MS Excel file to be used with ArcMap.
  • Add the data files to ArcMap and verify the information in the attribute tables
  • Join the Housing table with the table for the Wisconsin shapefile
  • Convert the field that holds the number of Households from a ‘string’ field type to a ‘number’ field type
  • Create a map and display information as a Graduated Color Quantity map. To find the average size, select the Total Population field as the Value and select the Total Households field for the Normalization

Objective 6: Build a Layout

Created map layouts for both of the maps that were created in Objectives 4 and 5. The NAD_1983_StatePlane_Wisconsin_Central_FIPS_4802_Feet projection was used for both maps and the necessary cartographic elements were added.

The final layout of each map can be seen in the Results section of this post.

Objective 7: Build a Web Map

Before a web map can be created, the map symbology and associated data has to be hosted on an ArcGIS server on the cloud, which then becomes a service. In this part of the lab, a service will be created for the County Populations map from Objective 4, which will then be used to create a web map/dynamic map.

Log in to ArcGIS Online from ArcMap

Create a Feature Service

  • Create a feature service from ArcMap document by going to File > Share As > Service…
  • Inside the ‘Service Editor’ dialog box, make sure the Capabilities are set up with the following settings:

  • Click over to the Item Description screen within ‘Service Editor’ and enter a summary, tags, and a description
  • Click Sharing to select who the service should be shared with
  • Click Analyze at the top of the ‘Service Editor’ dialog
    • Make sure all errors are resolved, and then Publish the service


Create a Web Map

  • Log in to ArcGIS online in a web browser and navigate to My Content
  • Click the three button dropdown in on the Feature Layer and select Add to Map. This opens the service in an ArcGIS Online map.
  • Configure the pop-up by changing the title, and selecting the fields to display, as shown below:

  • Click OK to save configuration changes
  • Be sure to save the map afterwards, and then it can be shared


Results

This section contains the maps that were created during this lab exercise.

Wisconsin Population by County - 2010 Census

Data used for this map was downloaded from the US Census Bureau Fact Finder website. A 'join' was used to connect the TOTAL POPULATION table to the Wisconsin shapefile. The original 'population' data field was imported as a 'string' field type, so this needed to be copied to a new field as a 'number' data type so that the quantitative information could be mapped.
The Southeast corner of Wisconsin appears to be the most heavily populated part of the state; the Madison and Milwaukee metro areas. The Fox Valley, Wausau, La Crosse, Chippewa Valley, and Hudson areas also stick out on this map as counties with relatively high populations.

Wisconsin County Home Density - 2010 Census

Data used for this map was downloaded from the US Census Bureau Fact Finder website. The Average Home Size was calculated using the following equation: TOTAL POPULATION/TOTAL HOUSEHOLDS = AVG HOME SIZE
According to this map, the Average Home Size tends to be higher in counties with higher population density. A possible explanation for the low Average Home Size in the northern counties could be that many of the home owners do not have children living with them anymore due to the homeowners now being empty-nesters or being around retirement age. The state-wide age distribution might be a good indicator of this.

Publish a Web Map

The County Population map was published to ArcGIS Online and can be accessed within the UWEC Enterprise group. A snippet of the map is shown below:


After configuring the pop-up, selecting a county on the map now shows the county name and the population:


After saving the map, it can now be shared in ArgGIS Online:


Sources

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