Frequently Asked Questions
Calibrating (also known as "rubbersheeting") is designed to eliminate arbitrary (both linear and non-linear) distortions in monochrome, grayscale, and color raster images: scanned graphic documents, geodetic plans, maps in raster format, etc.
To carry out calibration original documents must include points with known coordinates. These points can have a different position in the scanned image, caused by the deformation in original materials or scanning errors. By applying calibration, raster images are transformed so that the current coordinates of such points coincide with their known values.
Calibration can be applied to a selection set consisting of image fragments and also to a clipped area on the image. If several images have been selected, then the command will be applied to those that are visible and located on unlocked layers. If an image is not selected, then this command processes all visible images located on unlocked layers.
The calibration procedure needs to be applied before running the procedures of layering and vectorization. If there is non-linear distortion in the original image, then after vectorization a vector drawing is obtained, which is impossible to correct. To obtain a correct vector drawing, eliminate distortion before vectorization.