Geographic information systems enable geographers to study data obtained by:

• A. compiling data into charts and tables for reference and analysis.
• B. overlapping a series of maps with different themes to reveal spatial relationships.
• C. recording digital images of the earth's surface from a satellite.
• D. field observation and analysis of selected geographic parameters.

Answer: (C)

Geographic information systems are built to analyze spatial data, especially raster data that comes from remote sensing. Recording digital images of the Earth from a satellite provides georeferenced imagery that GIS can store, layer with other geographic data, and analyze to reveal patterns, changes, and relationships across space. This kind of satellite data is a primary input for GIS workflows, enabling tasks like land cover classification, change detection, and mapping over large areas.

Other data sources and methods—like simply compiling data into charts, field observations, or using map overlays to compare themes—are part of geographic work, but the data produced by satellite imagery is the type that GIS analyzes directly to study geographic relationships on a broad and scalable scale.