Finding by Algorithm the smallest circle that will encompass a group of shots

[Turnup]

I am beyond help as the data is provided to me as a written down list in x, y format which I can't currently do anything with.

To date I can't even think of a way of plotting it and generating a Target Overlay in order to then carry out a manual assessment.

Vic Thompson.

You can plot the data points in 2D using the scattergram type graphical function (chart) in Excel.

Superimposing a circle of arbitrary size and origin is quite trivial. Calculate x,y co-ords of a circle at suitable intervals. Take circle size as a fill in box and add an x and y offset fill in box as inputs to the calculation. Plot the points on the same chart. in a different colour. Change circle size and offsets to move it about and tweak until you get the best visual fit.

[BigEars]

You can plot the data points in 2D using the scattergram type graphical function (chart) in Excel.

Superimposing a circle of arbitrary size and origin is quite trivial. Calculate x,y co-ords of a circle at suitable intervals. Take circle size as a fill in box and add an x and y offset fill in box as inputs to the calculation. Plot the points on the same chart. in a different colour. Change circle size and offsets to move it about and tweak until you get the best visual fit.

Does he not need some indication of how the axes are scaled to get the relative size of the target picture correct?

[Turnup]

Does he not need some indication of how the axes are scaled to get the relative size of the target picture correct?

Well maybe yes and maybe no.


If results are required in units of distance then it will be necessary to know the scaling applied to the axes.


A perfectly correct result could also be produced in units of the existing x, y scales. E,g, group centre is at x 23.985, y 79.12 and group size is 15.1

This all falls apart if the x and y scale units are not the same though, but the data would then need to be scaled into common units OR for the really dedicated the "circle" generated could be substituted with an ellipse of appropriate scaling.

[Vic Thompson]

on my version of Excel you don't have the option of scaling the x and y axes to the same value on the screen. You can put numbers in but on the axes on the screen display have arbitrary values. I've plotted them but have to "pull one of the axes" to get an approximate square grid pattern. I've tried plotting the numbers in Powerpoint but can't set my version up for "circle centre positioning" so that's tedious as well.

Vic Thompson.