Autotek autocad raster design 2010 用户手册

NOTE Rubbersheeting is best suited for making minor transformations to an
image. For best results, start with a comprehensive and accurate network of survey
control points, then use match and scale before rubbersheeting to get the image
as close to the desired results as possible. It is also helpful to get a good spread of
the control points over the entire image. Where you don't have control points,
you can specify anchor points.

TIP If you prefer to use the command line to rubbersheet your images, type
-irsheet.

NOTE Use the match feature to get the image as close as possible to the desired
result before you begin rubbersheeting.

1 Click Image menu  ➤  Correlate  ➤  Rubbersheet.

2 Select the image to rubbersheet.

NOTE If there is only one image in the current drawing, that image is
automatically selected.

3 On the Rubbersheet dialog box, select a method: Triangular or Polynomial.

4 Choose one of the following rubbersheeting methods:

■

Manually add control points by picking directly from the image.
Follow steps 5 to 8.

■

Create a grid of destination points to which you can match source
points. Follow steps 9 to 15.

■

Import a list of saved control points by clicking the Import button
and choosing the .txt file from the Open dialog box.

NOTE When you click OK, Rubbersheet automatically saves the last control
points you enter to a file named LASTRS.txt in your Temp folder.

The Rubbersheet dialog box displays the exact coordinates of each source
point and destination point, and the amount of error (if any).

Pick control points

5 Click the Add Points button.

34 | Chapter 2   Inserting and Correlating Images