I am using VBA in Excel to model some alignment errors in a test fixture.
The output is a multiple series scatter chart of the data. If I calculate
the center and radius of a circle that fits a part of the data (least
squares fit method), how can I draw the circle on a chart?

Ron H.



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Hi,

The simplest way is to use a series to draw the circle.
Add an extra data series to the chart plotted as xy-scatter line no markers.

You can calculate the circle using basic trig formula.

Assume,
X Center in cell D1
Y Center in cell E1
Radius in cell F1
Range G1:G360
Circle XY points in range G1:H360

G1: =$D$1+(COS(ROW()*(PI()/180))*$F$1)
H1: =$E$1+(SIN(ROW()*(PI()/180))*$F$1)

copy down for 360 rows.

Cheers
Andy
--

Andy Pope, Microsoft MVP - Excel
http://www.andypope.info
"Ron H." <(E-Mail Removed)> wrote in message
news:476124a7$0$26631$(E-Mail Removed)...
>I am using VBA in Excel to model some alignment errors in a test fixture.
>The output is a multiple series scatter chart of the data. If I calculate
>the center and radius of a circle that fits a part of the data (least
>squares fit method), how can I draw the circle on a chart?
>
> Ron H.
>
>
>
> -----------------
> www.Newsgroup-Binaries.com - *Completion*Retention*Speed*
> Access your favorite newsgroups from home or on the road
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