On Thu, 6 Jan 2005 07:40:10 -0800, James Hurley <[EMAIL PROTECTED]> wrote: > What is the perpendicular distance between a point and a line? > > Application for which there is no redeeming social value: > if x3-x2 is 0 then > return (x1-x2) > else > put (y3-y2)/(x3-x2) into m -- The slope > return (m*(x1-x2)-(y1-Y2))/sqrt(1+m*m) > end if
Oddly, this is the answer to a question I asked on another users list for another programming environment, months ago -- netlogo-users. For a drawing utility, I needed to create a query that returns the set of "patches" (grid cells) with a perpendicular distance of N from the line between two arbitrary cells. Using your formula, I can now use this (netlogo) code: set line-patches ( patches with [ ( perpdist myself start-point end-point ) < n ] The prior solution was extremely verbose, convoluted, and slow. This seems like it will be faster. Thanks! ~~James _______________________________________________ use-revolution mailing list [email protected] http://lists.runrev.com/mailman/listinfo/use-revolution
