What a Map Leaves Out

A map is a choice about what to show. A road map emphasizes streets and distances; a rainfall map emphasizes water patterns. Neither can show everything. Before using a map, read its title, date, legend, scale and source. Ask what question it was made to answer.

Flat maps of a round Earth always distort something. Some keep directions useful for navigation while changing apparent areas; others keep relative areas closer while changing shapes. A globe can help you notice distortions. If a land region looks enormous on one map, compare it with another projection before deciding how large it is.

Maps can also leave out people. A transit map may show a bus line but not whether a stop has a ramp. A boundary map may show a line without explaining who lives on either side. Pair maps with local accounts, photos and current data when the human experience matters.