Chapter 2. Maps, Coordinates and Geographic Technology
Latitude and longitude. Latitude measures distance north or south of the equator (0°) up to 90° at each pole. Longitude measures distance east or west of the prime meridian (0°), which passes through Greenwich, England, up to 180° [1][4]. Key parallels are the Tropic of Cancer (about 23.5° N), the Tropic of Capricorn (about 23.5° S), the Arctic Circle (about 66.5° N) and the Antarctic Circle (about 66.5° S).
Map projections. A flat map cannot show a sphere without distortion. Projections preserve some properties (shape, area, distance or direction) at the cost of others [13].
| Projection | Preserves | Distorts |
| Mercator | Direction and local shape | Area, strongly near the poles |
| Robinson | Compromise of many properties | Some of each |
| Equal-area (e.g., Mollweide) | Relative area | Shape |
| Azimuthal | Direction from one point | Distance and shape away from the centre |
Map elements. Good maps include a title, legend, scale (ratio, verbal or bar), north arrow and source. Map types include physical, political, thematic (choropleth, dot density, flow) and topographic maps with contour lines [1].
Geographic technology
GPS and GNSS: satellite systems that fix position on Earth.
Remote sensing: gathering data about Earth from satellites and aircraft.
GIS (Geographic Information Systems): software that stores, analyzes and maps layers of spatial data [14].
Critical map reading. Maps reflect choices about data, classes, colours and projection, and these choices can mislead [15].
Review: Why does Greenland look nearly as large as Africa on a Mercator map, and how large is Africa in reality compared with Greenland?