Identifying Identical Points Using Overlapping Error Ellipses

[Scott S]

I'm not very familiar with statistics, so that's my main problem.
I use a least squares software to generate the coordinates of points and their associated 95% error ellipses. If the error ellipses meet a certain pre determined tolerance then I'm done.
However, I have a situation where I have two points which should be identical in Y and X coordinates but are 500 meters apart in elevation.
Of course the error ellipses are slightly different in size and orientation for each point.
Is there (a relatively easy to understand) method to determine if these points are identical based on the error ellipses?
I've done some research and can't find anything which relates to this particular problem.
So, any help or guidance would be greatly appreciated.
Thanks, Scott.

 

[mfb]

You can make an error ellipse for the difference between the points and see if zero is included. If their individual uncertainties are uncorrelated, this process is quite easy, if not it is more complicated and it will depend on how your measurements are done.

 

[Scott S]

Ah! Nice!
Thank you very much.