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function hp=drawvec(xo,yo,um,vm,varargin) |
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%DRAWVEC draw arrows for vectors |
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% DRAWVEC draws vectors on the current axes, given vector origins |
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% and component magnitudes. No scaling is performed; use |
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% VECPLOT to scale and draw the vectors. This function |
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% is called primarily by VECPLOT and returns the handle |
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% of the vector object drawn. |
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% |
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% Inputs: xo,yo - vector origins; arrow eminates from this point |
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% um,vm - vector magnitudes |
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% |
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% Outputs: hp - the handle to the vector object drawn |
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% |
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% PN/PV pairs accepted by DRAWVEC: |
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% ArrowAngle - angle (in degrees) that the arrow head wings |
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% make with the shaft. default=25 |
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% ArrowFac - Length ratio of arrow head relative to |
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% shaft. default=.25 |
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% |
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% All other pn-pv pairs are passed to LINE |
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% |
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% Call as: hp=drawvec(xo,yo,um,vm,pn1,pv1,...); |
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% |
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fac = 3.14159/180.; |
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% Default PN/PV for DRAWVEC |
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ArrowAngle=25; |
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ArrowFac=.25; |
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|
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% Strip off parameter/value pairs in varargin not related to |
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% "line" object properties. |
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k=1; |
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while k<length(varargin), |
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switch lower(varargin{k}), |
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case 'arrowangle', |
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ArrowAngle=varargin{k+1}; |
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varargin([k k+1])=[]; |
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case 'arrowfac', |
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ArrowFac=varargin{k+1}; |
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varargin([k k+1])=[]; |
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otherwise |
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k=k+2; |
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end; |
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end; |
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if length(varargin)<2 |
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varargin={}; |
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end |
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|
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% Conv to rads |
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arrowtheta = ArrowAngle*fac; |
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|
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% columnate the input vectors to ensure they are |
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% column-vectors, not row-vectors |
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xo=xo(:); |
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yo=yo(:); |
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um=um(:); |
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vm=vm(:); |
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|
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% compute and draw arrow shaft |
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xe = xo + um; |
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ye = yo + vm; |
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arrowmag = ArrowFac*(sqrt((xo-xe).*(xo-xe)+(yo-ye).*(yo-ye))); |
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shafttheta = -atan2((ye-yo),(xe-xo)); |
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xt = xe-arrowmag.*cos(arrowtheta); |
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yt = ye-arrowmag.*sin(arrowtheta); |
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x1 = (xt-xe).*cos(shafttheta)+(yt-ye).*sin(shafttheta)+xe; |
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y1 = (yt-ye).*cos(shafttheta)-(xt-xe).*sin(shafttheta)+ye; |
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xt = xe-arrowmag.*cos(-arrowtheta); |
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yt = ye-arrowmag.*sin(-arrowtheta); |
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x2 = (xt-xe).*cos(shafttheta)+(yt-ye).*sin(shafttheta)+xe; |
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y2 = (yt-ye).*cos(shafttheta)-(xt-xe).*sin(shafttheta)+ye; |
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x=ones(length(xo),6); |
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y=ones(length(xo),6); |
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x=[xo xe x1 xe x2 NaN*ones(size(xo))]'; |
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y=[yo ye y1 ye y2 NaN*ones(size(yo))]'; |
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x=x(:); |
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y=y(:); |
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hp=line(x,y,varargin{:}); |
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% |
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%LabSig Brian O. Blanton |
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% Department of Marine Sciences |
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% 12-7 Venable Hall |
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% CB# 3300 |
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% University of North Carolina |
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% Chapel Hill, NC |
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% 27599-3300 |
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% |
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% brian_blanton@unc.edu |
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% |
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