www.pudn.com > geometric.rar > polydist.m, change:2004-08-13,size:2951b

function dmin = polydist(x,y,datum,icol)  % dmin = polydist(x,y,datum,icol) % dmin = polydist(x,y,datum) % % POLYDIST is the minimum distance from a polynomial to a datum line % % x,y 	= coordinate vectors of polygon  % datum = 4-vector, [x1 y1 x2 y2] definining 2 pts on datum % icol 	= color for plotting, 'y','m','c','r','g', or 'b' % ====================== Default = 'b' ======================= % % T.N.Bishop  Oct.93 % % NOTE: It is illegal for you to use this software for a purpose other % than non-profit education or research UNLESS you are employed by a CREWES % Project sponsor. By using this software, you are agreeing to the terms % detailed in this software's Matlab source file.   % BEGIN TERMS OF USE LICENSE % % This SOFTWARE is maintained by the CREWES Project at the Department % of Geology and Geophysics of the University of Calgary, Calgary, % Alberta, Canada.  The copyright and ownership is jointly held by  % its author (identified above) and the CREWES Project.  The CREWES  % project may be contacted via email at:  crewesinfo@crewes.org %  % The term 'SOFTWARE' refers to the Matlab source code, translations to % any other computer language, or object code % % Terms of use of this SOFTWARE % % 1) Use of this SOFTWARE by any for-profit commercial organization is %    expressly forbidden unless said organization is a CREWES Project %    Sponsor. % % 2) A CREWES Project sponsor may use this SOFTWARE under the terms of the  %    CREWES Project Sponsorship agreement. % % 3) A student or employee of a non-profit educational institution may  %    use this SOFTWARE subject to the following terms and conditions: %    - this SOFTWARE is for teaching or research purposes only. %    - this SOFTWARE may be distributed to other students or researchers  %      provided that these license terms are included. %    - reselling the SOFTWARE, or including it or any portion of it, in any %      software that will be resold is expressly forbidden. %    - transfering the SOFTWARE in any form to a commercial firm or any  %      other for-profit organization is expressly forbidden. % % END TERMS OF USE LICENSE   % get slope for datum m = zeros(size(y));  %slope of datum m = (datum(4)-datum(2))/(datum(3)-datum(1)); if(datum(3) == datum(1))    m = 1/eps; end b = datum(2) - m*datum(1);  %find dist from each point in polygon to datum line msq = m.^2; denom = 1+msq; xd=zeros(size(y));   %intercept of datum for each perpendicular yd=zeros(size(y));   %y coord of intercept of datum  d = zeros(size(y));  %dist.along perpendicular %     perpendicular is perpendicular to the datum and it also %     intersects the polygon point (x(i), y(i)). xd =( x+m.*(y-b) )./denom; yd =( x*m+msq*y+b )./denom; d = sqrt((x-xd).^2 + (y-yd).^2); dmin = min(d); imin = find(d == dmin); % plot segment (if icol is called by the function) if(nargin > 3)    hold on   xtmp=[x(imin) xd(imin)];   ytmp=[y(imin) yd(imin)];   plot(xtmp,ytmp,icol) end