Earth Observations and Imaging: A journal of human-directed remote sensing from the Space Shuttle and International Space Station

User's Guide to
An Astronaut's View of California

Bill Daley and Fred Brumbaugh
Hernandez Engineering, Earth Sciences and Image Analysis, NASA Johnson Space Center

A photograph of a location on Earth taken by an astronaut

These images presented in our database are very easy to use and understand. Most of the images are natural color photographs. Since these photos are in natural color many of the features are easy to identify. For example, water appears as different shades of blue, unless sediments are present (in which case the water can appear as a variety of colors, including browns, tans, or yellows). Vegetation can be seen as dark blues, shades of green, or even browns; while sparsely vegetated deserts are generally shades of browns or yellows, depending upon parent soils and weathering conditions of the surrounding rocks. In addition to the natural color photographs, several color infrared photographs have also been included in the database. Remember that color infrared photography generally shows green vegetation as shades of red and water surfaces are generally dark, usually black or deep blue.



Orientation of California Images


The California images are orientated in the look direction that the astronaut's took the photographs. The true North is not always at the top of the frame. Please consult a map and identify approximately three features or landmarks to determine the North and South locations.

A photograph of a location on Earth taken by an astronaut


Scale of California Images


A photograph of a location on Earth taken by an astronaut

Each image may be a different scale. Astronauts use different lens combinations that result in images that have a variety of look angles and scales. Spacecraft altitude, which varies from one mission to the next, is also a factor in determining the scale of a photograph. To determine the photo's scale, use a map of known scale and identify two features on both the map and photograph. Using this information and known map scale, you can compute the scale of your photograph. This scaling technique is only true for near-vertical photography. Remember that when viewing oblique photography the scale will continue to change as a function of the ground distance from the camera.

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