Hi Simon,
Alternatively you can simply use Excel to calculate the angle, since it is equal to the angle between the poles to the planes (which are easily found from the strike/dip data). Bill Owens recently posted the equation for the angle between two lines, and I have included Bill's original message to Geotectonics below in case you no longer have it.
Best wishes,
Tony Morris
=============================
Dr. Antony Morris
Department of Geology,
School of Geography & Geology,
University of Plymouth,
Drake Circus, Plymouth PL4 8AA.
Tel: +44 1752 233120
Fax: +44 1752 233117
e-mail: [log in to unmask]
http://www.geol.plymouth.ac.uk/AcadStaff/AMORRIS/AMorris.html
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Bill Owens' original message:
From scratch:
If l1,m1,n1 and l2,m2,n2 are the sets of direction cosines for two
lines, the angle between the lines, say A, is given by
cos A = l1*l2 + m1*m2 +n1*n2
For a line with azimuth Az and plunge Pl, where x,y,z axes are
taken along N,E,down, the direction cosines are
l = cos Pl cos Az
m = cos Pl sin Az
n = sin Pl
All very Excel-able. (Sorry about the l's ('ell') and the 1's (one).)
Bill
*********************************************************
Dr W H Owens E-Mail: [log in to unmask]
School of Earth Sciences Phone: +44-(0)121 414 6137
University of Birmingham Fax: +44-(0)121 414 4942
Edgbaston
Birmingham B15 2TT
UK
*********************************************************
-----Original Message-----
From: Simon Kattenhorn [mailto:[log in to unmask]]
Sent: 24 June 2003 23:20
To: [log in to unmask]
Subject: Software for measuring angles between planes
Hi
Can anyone direct me to some freeware or shareware that allows one to
calculate the angle between two planes given the strike and dip of each
plane?
Thanks much.
Simon Kattenhorn
University of Idaho
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