They range in appearance and purpose from a simple freehand line drawing of how to get to a friend's house to a complex multicolor depiction of atmospheric conditions used in weather forecasting. No single map can show everything, and the features depicted on each map are selected to fit a particular purpose. Maps can depict not only visible surface features such as rivers, seacoasts, roads, and towns, but also underground features such as subway systems, tunnels, and geographic formations. They can depict abstract features such as political boundaries, population densities, and lines of latitude and longitude. In the classroom, maps serve both as repositories of many kinds of geographical information and as an essential means of imparting that information to students.
Maps constitute a critical element of geography education.
However, they do have limitations. One major limitation is that it is not possible to accurately represent the round Earth on a flat surface without distorting at least one Earth property, such as distance, direction, or size and shape of land and water bodies. No single map can accurately depict all Earth's properties, so it is essential that students know how to look at a given map and know which properties are rendered correctly and which are distorted. Globes present an essential overview of Earth, and they can be very useful in the teaching of such concepts as location, spatial patterns, Earth-Sun relationships, and time. In addition to maps and globes, graphs, diagrams, aerial and other photographs, and satellite-produced images also provide valuable information about spatial patterns on Earth.