recalculating parameters of the standard deviational ellipse

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04-20-2012 08:07 AM
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New Contributor
Hi colleagues,
I am working with ArcGIS 10.0 (SP 4) and are trying very hard to recalculate the XStdDist and YStdDist values for the Standard Deviational Ellipse ArcGIS offers me by hand (using Excel).
I was able to reproduce the angle of rotation but not more. The values I get for the axes of the ellipse do not differ from each other and are completely different from the ArcGIS results.
I used the formulars in the ArcGIS Help but somewhere I am doing a fatal mistake.
Could anybody help me with a hint? I am desperately looking for a solution.
Thanks so much in advance
Susanne
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3 Replies
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MVP Esteemed Contributor
and what are the result summaries between the two?
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New Contributor
Thanks for your reply. The sum is simply about the doubled value since they are almost the same.
I have attached the excel sheet to my mail because its hard to explain in words.
I am sure I made a simple but essentail mistake and although trying to solve I am some kind of "blind".
Thanks
Susanne
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New Contributor
Dear colleagues,
I did find the mistake - the formulas contain a mistake - instead of a minus there seems to be a plus in the formula for the standard dev of the y-axis. Additional there is a scaling factor implemented.
Thanks
Susanne
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