What are base maps created from?

Base maps are essential tools in various fields, including education and geography, as they provide foundational geographical and spatial information upon which other data can be layered or analyzed. They are primarily created from a combination of aerial and field surveys.

Aerial surveys involve capturing images and data from above the Earth's surface, typically using aircraft or drones, and collecting detailed topographical information. Field surveys complement this by collecting data on-site, where cartographers can measure and observe physical features directly. This combination ensures that base maps are accurate and reflective of real-world features.

The other answer choices represent methodologies or sources that might contribute to a broader understanding of geography (such as satellite imagery, geological studies, or personal exploration), but they do not comprehensively encompass the foundational process of creating base maps. Therefore, aerial and field surveys are the primary means of creating accurate and useful base maps, which serve as the starting point for further geographic analysis and application.