Autotek autocad raster design 2010 用户手册

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The limit of ten edits applies to operations that change the image data, such
as Rubbersheet, Remove, Crop, Histogram, using a vectorization tool with the
REM setting, and so on.
NOTE If you try to undo more than ten edits, then the eleventh undo undoes
every edit you made to the image since you last saved it.
Snapping to COGO Points
Coordinate geography points, or COGO points, can store information such
as a point node, point number, northing and easting values, and elevation.
COGO points are the foundation for any civil engineering or surveying project.
When you use Raster Design with a geographic application, you can substitute
COGO points anytime Raster Design asks you to enter a point. This is especially
useful for rubbersheeting or matching operations.
There are three ways to specify a COGO point in Raster Design:
Enter .p when prompted to enter a point, then enter a COGO point
number.
Enter .g to select a COGO point using the mouse.
Enter .n when prompted to enter a point, then enter northing and easting
values that correspond to a COGO point.
Cleaning Up Images
Use cleanup commands to correct errors that occur during the scanning
process.
Misaligned drawings, dust on the scanning bed, and mistakes with scanning
software can all be corrected using the following Cleanup commands:
Deskew. Rotate an image so that it matches the rotation angle of a vector
drawing or another image.
Despeckle. Remove speckles or stray pixels that can appear in an image
when you scan drawings or blueprints that are dirty or wrinkled.
 (page 381). If, for instance,
the image is distorted due to paper shrinkage or optical distortions in the
scanning process, the Bias tool can correct the aspect ratio by resizing the
image in one or two dimensions.
82 | Chapter 6   Modifying Images