Maps and Globes

An Earth Reference System

Maps and Globes Maps and globes show shape, size, and position of Earth’s surface features. Map – Model on a flat surface of Earth’s surface as seen from above. Globe – A sphere that represents Earth’s entire surface.

Map Projection Map projections use lines on a flat map to show landmasses.

Mercator Projection Mercator projection – lines of latitude and longitude are straight and parallel. Landmasses near the equator are slightly out of shape. Landmasses near the poles are more out of shape.

Equal Area Projection Equal Area Projections – show the correct size of landmasses, but the shapes near the edge look stretched and curved

Conic Projection Lines of longitude appear as straight lines while lines of latitude are curved. There is little distortion. Can show only limited parts of Earth’s surface.

Topographic Maps Topographic map: Map that shows the surface features of an area

Isolines Isolines: A line on a map, chart, or graph connecting points of equal value

Surface Air Pressure

Air Temperature

Dew Point Temperature

Surface Pressure Change Map

Contour Lines Contour Lines: connect points of equal elevation Mapmakers use contour lines to represent elevation, relief and slope Contour interval: Change in elevation from contour line to contour line Index lines: Contour lines with labeled elevation, usually darker in color

Interpreting Contour Lines Steepness: Lines close together show steep topography Lines far apart show gradual topography V shapes indicate a river Depressions are shown by contour lines with hash marks