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Geospatial Data

Subject guide to finding and using geospatial data. Includes tutorials for using elevation data to make contours, and using aerial imagery layers to output imagery even more efficiently than Google Earth Pro can.

Spatial and Numeric Data Librarian

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Nicole Scholtz
Clark Library
(734) 936-2932

Frequently Used Data Sources

This is a list of data sources that we frequently use when working with people in the SAND lab. It is not exhaustive, but it can be a good place to start!

Tips for Googling for GIS Data

Try searching for <placename> <keywords>. You may have to try different combinations to get to the GIS data site for the place you want -- if it even exists!

keyword examples:

open data


geo data


Your Research Question

Define Your Research Question

Try to state your research question without describing the sources or data you will use to answer the question.

Think about Your Method of Visualization or Analysis

What sort of analysis do you plan to do? Do you need to make a map to illustrate a point? Will you be using GIS software, such as ArcGIS, ERDAS, or Geoda, to do analysis?

Defining Your Topic and Unit of Analysis

When you define your topic and unit of analysis, you should look at your research question and ask:

  • What are the specifics of the data I need to use to answer my research question? What is my topic? What unit of analysis, geographic unit, and time unit (frequency) do I need? Do I need time series data?

Define Your Topic

Use specific language when defining your topic. This will help you identify a variable or variables.


  • I'm looking for the percentage of people living below the poverty line in areas where hurricanes frequently hit.

Identify Unit of Analysis

Who or what is being described by your variable(s)?


  • Individuals, families, households
  • Institutions (companies, schools, non-profits, health facilities)
  • Products (commodities, stocks, currencies)

Identify Time Frame and Frequency

For what point in time do you want to know this about the people, institutions, or products you identified? How often do you want to know it about them?


  • As recent as possible, plus data from 10 and 20 years before that
  • Every month in 1995 and 1996

Identify Geographic Unit

What part of the world is your research question concerned with?


  • Counties in Michigan
  • Countries currently in the EU
  • Businesses headquartered in China

Identify Whether this is Time Series Data

Are you looking for data collected at regular intervals over time? Identifying what sort of time series may be helpful as you search for data.

  • Cross sectional: collected at the same point of time for several individuals
  • Longitudinal/Panel: data collected at a sequence of time points for each of a sample of individuals
  • Time Series: data collected at a sequence of time points, usually at a uniform frequency
  • Pooled cross sectional time series: mixture of time series data and cross-section data

* Adapted from Barbara Mento's guide to Finding Data at Boston College