1.1 Introduction to Maps

Maps as spatial tools

A map is a two-dimensional (flat) representation of Earth's surface or a portion of it, used to display spatial data and analyze patterns. Cartography is the science and art of making maps. Maps help geographers visualize spatial relationships, distributions, and patterns that are hard to see from raw data alone.

Reference maps vs. thematic maps

Reference maps show absolute locations of places and geographic features (e.g., political maps, road maps) — they answer 'where is it?' Thematic maps display the spatial distribution of a specific theme or data set (e.g., population density, climate) — they answer 'why is it there?' Common thematic types include choropleth, dot density, isoline, and graduated symbol maps.

Map distortion and projections

Because Earth is a sphere, transferring its surface to a flat map always causes distortion in area, shape, distance, or direction. A map projection is the method used to make this conversion. Common examples: Mercator (preserves shape/direction, distorts area near poles) and Robinson (balances distortion across all properties).

Key terms

Cartography

The science and art of creating maps.

Reference map

A map showing the absolute location of places and geographic features; answers 'where is it?'

Thematic map

A map displaying the spatial distribution of a specific theme or data set; answers 'why is it there?'

Map projection

A method for converting Earth's curved surface into a flat map, always causing some distortion in shape, area, distance, or direction.

Choropleth map

A thematic map that uses shading or color to represent data values across defined areas.

Try an AP-style question

Which map projection preserves shape locally but greatly enlarges areas near the poles?

1. Goode homolosine
2. Mercator
3. Robinson
4. Peters