Best Fit Circle

Function

This command draws a least-squares best-fit circle based on points on the perimeter. The program handles four or more perimeter points. A design point for the circle center can optionally be specified. The report shows the residuals for each point, the residuals standard deviation, the difference between the design point and the circle center, and the circle parameters. The residuals are calculated as the perpendicular distance from the point to the circle. The program generates a report.

Prompts

Select points from screen or by point number [<Screen>/Number]? N
Point numbers: 2-6
Point numbers (Enter to continue): press Enter
Enter design center point# (Enter for None):

Sample Report:

Source Coordinates
Point# Northing Easting Residual
2 5253.198 5070.233 0.126
3 5246.623 5084.077 0.045
4 5232.963 5078.608 -0.131
5 5235.610 5065.105 0.217
6 5247.392 5064.165 -0.264
Residuals Standard Deviation: 0.174
Circle Center: 5242.678,5073.785 Radius: 10.977
Design Center Point#: 1
Design Center: 5242.718,5073.688
Center Distance Difference: 0.105
Best Fit Circle

Pulldown Menu Location: COGO
Keyboard Command:
bfitcir
Prerequisite: Four or more points
File Name: \lsp\crdutil.arx