Chapter 3: Work With Data
In Chapter 2, you gained some experience with data through creating geographic vector features and manipulating raster imagery and maps. This chapter digs deeper into data processing and manipulation. Dealing with data often accounts for the majority of time spent on any given GIS project. It can be both confusing and tedious. A strong understanding of how datasets are put together and the different ways they can be manipulated will come in handy for virtually any GIS application.
Like Chapter 1 and unlike Chapter 2, Chapter 3 revolves around a single ArcGIS Pro project from start to finish. The sections must be completed in the given sequence to successfully complete the chapter.
Goal: Process U.S. Census data to create a quantitative thematic map.Chapter Outcomes
In this chapter, you will learn how to:
- Find and download geographic and tabular U.S. Census data,
- Calculate the value of derived attributes,
- Select feature data manually, by attribute, and by location, and export the selected features to a new dataset,
- Change the coordinate reference system of a dataset,
- Prepare a spreadsheet for import into GIS,
- Join tabular data to features, and
- Use attribute values to symbolize features on a quantitative thematic map.
Materials Needed
You will download all of the data used in this chapter from other websites, so you will not need any datasets to start with. In addition to ArcGIS Pro, you will need a desktop spreadsheet program, preferably Microsoft Excel (LibreOffice Calc may work as an open-source alternative). An online spreadsheet app (e.g., Google Sheets, Office 365 Online) will not provide the functionality needed; you must have the desktop version.
The GIScience concepts that accompany this workbook chapter are contained in Chapters 5 and 6 of the companion textbook, Essentials of Geographic Information Systems by Jonathan Campbell and Michael Shin. It is recommended that you read these chapters before proceeding, as the concepts from each chapter are interwoven throughout the exercises of this workbook chapter. Answer the first teachback of the chapter, below, before proceeding.
Teachback 1
Go to the website PolicyMap. This site presents an interactive map visualizing a wide variety of geographic variables. From the menus along the top of the page, choose a variable that you are interested in to show on the map. Answer the following:
- What variable did you choose?
- How does the map visualize (show) the variable?
- What information does the map communicate about the variable? (Think deeply about what the map shows—the raw high and low values, their units of measure, geographic patterns you see, and what might be left out or missed by showing the data this way).
