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GRASS Help System |
i.rectify -
i.rectify is the imagery function that rectifies an image by computing a coordinate transformation for each pixel in the image using the transformation coefficient matrix created by the GRASS program i.points. i.rectify plugs the coefficients computed in i.points into an equation and then converts x,y coordinates to standard map coordinates for each pixel in the image. The result is a planimetric image with a transformed coordinate system.
i.points must be run before i.rectify and both programs are required to rectifiy an image. An image must be rectified before it can reside in standard coordinate LOCATION, and therefore, be analyzed with other map layers in the standard coordinate LOCATION. Upon completion of i.rectify, the rectified image is deposited in the target standard coordinate LOCATION. This LOCATION is selected using i.target.
Manual entry for i.rectify