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Arc Recognition Options |
WinTopo Pro includes a function to fit smooth arcs around the curved features of the image during the vectorisation process. (This option is not available on the Freeware version)
Select the Vector Extraction Options... option on the File menu, or click the toolbar button. The Options window will appear. Select the Arcs tab.
After vectorising, the arcs are shown in blue and the straight lines are shown in the usual green.
The Arc Recognition checkbox controls whether or not arc fitting is used during vectorisation. If this option box is not selected then arc fitting will not be used. If this option box is selected then the following two options come into effect.
Here is a pictoral example, using an 'S' shaped line of pixels. The image is shown at high magnification.
![]() | Tolerance = 0.5 |
![]() | Tolerance = 0.8 |
![]() | Tolerance = 1.2 |
The default for the tolerance value is 0.8 which gives a good compromise for most image types.
The Minimum Curve value represents a percentage of a full circle (100 is a full circle, 50 is a semi-circle, 25 is a quarter-circle). For example, if the value is set at 50, then it means that WinTopo Pro cannot fit an arc which is less than a semi-circle.
The default value for the Minimum Curve is 4, which means that WinTopo Pro doesn't produces any arcs which are less that 4 percent of a circle. Arcs which are less that 4 percent of a circle start to look like a straight line.
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