by **Glen Cameron** » Sun Jan 26, 2003 7:02 am

What this is telling you is the distance from the beggining of the curve to the radial point is not equal to the distance from the end of the curve to the radial point. Because they are not equal, when you inverse the 3 points we will not handle it as a curve (they have to be equal to be a curve). Instead it is calculated, as you mentioned, as an Angle left and right as well as a Baseline Offset calculation.

There are two ways to correct for this situation.

1) Reset the location of the radial point, being it is not really the radial point, being it is not accurately set. You can do this by using the Distance Distance intersection calculation in COGO.

2) Often the inaccuracy in the location of the radial point is due to rounding errors from other programs. To allow you to still use the point, as it is set, and get a curve we do have a FUDGE FACTOR that you can control.

This fudge factor is actually our Point Protection Tolerance. On the General Configurations Dialog box, the Point Protection Tolerance, controls if the curve inverse will give the curve or the alternate info, as mentioned above.

As an example;

If the first inverse was equal to 107.3033

and the second equal to 107.2933, the radial point is not perfect and if the Point Protection Tolerance is set to 0.001 or smaller, then we get the 3 point inverse which displays the angle left and right as well as the Baseline Offset.

Change the Point Protection so it is equal to 0.01 and now the COGO 3 point inverse will give you the curve information, and draw the curve on screen, if the toggles are set to do so. The Radius used to calculate the curve info is 107.3033, in this example.

Cheers,

Glen W. Cameron, C.E.T.

City of North Bay, Ontario