Here's why:

* Geologic maps depict the distribution of different rock types and geological formations at the Earth's surface. They use colors, patterns, and symbols to represent various rock units, their ages, and structures like faults and folds.

* They are essential tools for understanding the geological history of a region, identifying potential mineral resources, assessing ground stability, and planning infrastructure projects.

Other types of maps might show related information, but they are not focused on rock types:

* Topographic maps show elevation and landforms.

* Soil maps depict soil types and characteristics.

* Hydrographic maps focus on water bodies and features.

Let me know if you'd like more information about geologic maps!