The Sources & Power of Geographic Data (College Board AP® Human Geography): Study Guide

Sources of spatial information

• Spatial information is information about places, and about the people, objects and phenomena found in them

• Much of it comes from written accounts and first-hand records:

  • Field observations — notes and measurements recorded by travelling to a place

  • Media reports — news coverage and journalism about a place or an event

  • Travel narratives — written accounts by people who have visited a place

  • Policy documents — government plans, legislation and planning records

  • Personal interviews — asking people directly about a place and how they experience it

  • Landscape analysis — studying and describing a landscape to assess human impact on it

  • Photographic interpretation — analyzing aerial, satellite or ground-level photographs

• These sources vary in reliability, so geographers usually combine several of them to build an accurate picture of a place

The power of geographic data

• Geospatial and geographical data — including census data and satellite imagery — are used at every scale to make decisions

Personal decisions

• House buyers compare data on school catchments, crime rates and commute times before choosing where to live

• Navigation apps use live location and traffic data to pick a route

Business decisions

• Retailers use customer zip codes and income data to decide where to open a new store

• Median household income guides whether a developer builds high-end or affordable housing

• Businesses combine population density with competitor locations to find underserved markets

Organizational decisions

• Aid agencies map where need is greatest — disease outbreaks, food insecurity, or damage after a disaster — so help reaches the worst affected areas first

• Campaign groups use spatial data as evidence of inequality, for example by mapping which neighborhoods have no clinic within walking distance

Governmental decisions

• Census tracts divide the United States into small areas of roughly 1,200 to 8,000 people, so data can be analyzed at neighborhood level

• Population density and age structure show where new schools, hospitals and clinics are needed

• Spatial patterns in income and deprivation are used to decide which areas receive funding first

• Census results are used to reapportion seats in the House of Representatives and to redraw voting district boundaries

Limitations of geographic data

• The scale at which data is collected changes how useful it is

  • Collecting literacy data at a national scale masks large differences between urban and rural areas

  • Without knowing where illiteracy is concentrated, policymakers cannot target spending effectively

• Groups that are undercounted, or missing from a dataset altogether, are easily left out of the decisions based on it