__/ [ ror7 ] on Thursday 02 March 2006 18:32 \__
> __/ [ end18 ] on Thursday 02 March 2006 05:52 \__
>
> > am..
> >
> > I want to comapre two Line in 2 dimension.
> >
> > Two lines have some points (like a Path)
> >
> > in brief... I want to know two path's similarity.
>
> what do you mean by similarity?
>
> in 2D space, points describing lines wit the same slope are colinear.
>
> in Nspace, I think you can research something called the "dot" or
> inner product. and from that you can determine if lines are parallel or
> orthogonal.
>
> the "cross" or outer product can be used to determine the same thing,
> since i believe the magnitude of the cross product will provide the
> area between the parallelogram formed by the two lines.
>
> maybe if people knew what you were trying to accomplish, they could
> provide more help.
You probably ought to look at the direction of the two paths at any given
pointtopoint transition and estimate the degree of dissimilarity
(disagreement). You could, for example, take the tangent of the two lines at
any segment and subtract the two, accumulating those differences along the
path. Whether you have equalsized lines, I do not know. You haven't
described the data in enough detail.
Best wishes,
Roy

Roy S. Schestowitz, Ph.D. Candidate (Medical Biophysics)
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