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| Glossary |
| Click a word to find out its meaning! |
| image | sonar | satellite| elevation model | bathymetry remote sensing | remotely sensed images | mosaic |
| image |
a picture showing how something looks. It can be a photograph captured on film, a digital (stored on a computer) picture of the Earth's surface, or a digital picture created from measurements like temperature, brightness, or height (elevation). [ TOP of Page] [ TOP of Glossary ] |
| sonar |
an instrument/camera used to take pictures underwater using sound. A boat tows the camera behind it. The camera is usually called a fish. It sends out the sound and measures how long it takes for the sound to come back to it, and how loud it is. A computer keeps track of the information and can makes pictures of the bottom of an ocean, lake, or river. [ TOP of Page] [ TOP of Glossary ] |
| satellite |
a small spacecraft that orbits the Earth hundreds of miles above us. Some satellites have special cameras that can take pictures of the Earth. Example of an image (or picture) taken by camera on-board a satellite of the San Francisco area. Can you find the area showing the Golden Gate Bridge in the above image? (Answer) [ TOP of Page] [ TOP of Glossary ] |
| elevation model |
an image (or picture) showing how high each point on the ground is. The brighter the point, the higher the ground is at that point. Example: The San Francisco Bay area: the first picture on the page is a digital elevation model. Click the link to learn more and see 3D images we can create from digital elevation models! Learn more about digital elevation models (DEMs) by creating your own 3D model! [ TOP of Page] [ TOP of Glossary ] |
| bathymetry |
this is an underwater elevation model, so it can be used to show how deep the water is. The brighter the point, the deeper the water. example: Gulf of the Farallones In the image linked above, did you notice the lighter colored areas that look like veins or rivers? Those are canyons. The two darker blobs on the lower left are mountains beneath the ocean! [ TOP of Page] [ TOP of Glossary ] |
| remotesensing |
gathering information about something from a distance. Terrestrial refers to the Earth, so Terrestrial Remote Sensing means gathering information about the Earth from a distance. Remote sensing is also used to gather information about planets and the stars. [ TOP of Page] [ TOP of Glossary ] |
| remotely sensed images |
images (or pictures) collected using remote sensing tools, such as the special cameras on-board satellites and ships. [ TOP of Page] [ TOP of Glossary ] |
| mosaic |
an image (or picture) made up of two or more smaller images. For instance a sonar mosaic is created from long strips of images collected along the path of the ship. example: in the Monterey Bay image linked here (below), you can see the strips of sonar images that make up the entire mosaic. The blue lines show the direction the ship was moving in different sections of the Bay.
Click here to see a sonar strip image and learn why sonar mosaics can be like big jigsaw puzzles! Another reason the above image is a mosaic is because it contains two different types of images - the sonar mosaic of the seafloor combined with a picture of the on-land area. These are labeled in red. [ TOP of Page] [ TOP of Glossary ] |
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