Earthrise was captured by the Apollo 8 crew. NASA

Did you ever want to learn to read a map? How about learning topography? Well, NASA’s Earth Observatory offers tips and strategies for interpreting several kinds of satellite images.

Look for patterns, shapes, and textures

A key skill to develop is recognizing distinctive patterns on maps to identify specific features. For example, rivers, lakes and oceans have a multitude of possible shapes. Farms usually have a geometric shape, like a circle or rectangle, unlike the patterns in nature, which are random. For example, when a forest is cut down the path is usually square or has a series of herring-bone-like lines that form along roads. Any straight line in an image is most likely human-made, which could be a road, canal, or some kind of boundary made visible by land use. Geology's marks on the landscape are usually easy to find; volcanoes and craters are circular, and mountains ranges tend to run in long wavy lines. These geological features create visible textures. Canyons are squiggly lines framed by shadows, and mountains look like wrinkles or bumps from above.

Look for patterns, shapes, and textures
Straight lines and geometric shapes in this image of Reese, Michigan, are a result of human land use. Roads cut diagonally across the squares that define farm fields. (NASA Earth Observatory image by Jesse Allen and Robert Simmon, using ALI data from the NASA EO-1 team.)

What about the topography? The features explained above can affect clouds by influencing the flow of air in the atmosphere. Mountains force air up where it is cool, and islands create turbulence that results in swirling cortices or wakes in the clouds.

Central Chile and Argentina offer a wide range of geographic features, including snow-covered mountains, canyons, and volcanoes. (NASAimage courtesy Jeff SchmaltzLANCE/EOSDIS MODIS Rapid Response Team, GSFC.)

Define Colors

When observing water from space, the color usually appears black or dark blue because the sediment reflects light, which colors the water.

Plants have different shades of green; grasslands tend to be a pale green while forests tend to be a dark green. Land for agriculture is usually brighter than natural vegetation. Plant colors change with seasons. In spring, the vegetation usually is paler than summer vegetation when it is more dense. Fall vegetation can be red, orange, yellow and tan.

The forests covering the Great Smoky Mountains of the Southeastern United States change colors from brown to green to orange to brown as the seasons progress. (NASA images courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC.)

When looking at cities, densely built areas are usually silver or gray from the concentration of concrete. The contrast between Warsaw’s modern and historic neighborhoods is easily visible by satellite.

City map image
The new Stadion Narodowy is brilliant white. Śródmieście (Inner City) was rebuilt after World War II and most areas appear beige or gray. But some neighborhoods rebuilt with older-style buildings, such as the red tile and green copper roofs of Stare Miasto (Old Town). NASA/USGS Landsat