Raster File.
Is another name for a digital image. The file is organized in rows and columns of values which contain either a color or gray value.

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World File
A small text file that describes how an image relates to a given coordinate system. The world file contains 6 lines describing insertion point, pixel size, and rotation.

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Geo-referenced
Describes the fact that an image has been linked in some way to some geographic coordinate system. There are many different coordinate systems and several ways to create this relationship, geo-referenced just means that the relationship exists and that coordinate data could be extracted from the image.

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Vector Map
Another term to describe what is delivered as a normal CAD file. A collection of coordinate positions displayed as lines and symbols in a corresponding CAD program.

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Orthorectification
The process of eliminating all distortions from aerial photography including those from camera position and attitude, lens distortions, and relief displacement (distortion caused by height variation). An orthophoto should be a measurable product as accurate as a map at the same scale for objects on the ground.

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Pixel
One of the row,column addresses that makes up a raster or image file. This is the grey, or color value represented at a particular place in the image.

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