lab_sea/matlab/myquiver.m

function hh = myquiver(arg1,arg2,arg3,arg4,arg5,arg6)
%MYQUIVER Quiver (or velocity) plot.
%       MYQUIVER(X,Y,U,V) plots the velocity vectors with components
%       (u,v) at the points (x,y).  The matrices X,Y,U,V must all be
%       the same size and contain the cooresponding position and
%       velocity components (X and Y can also be vectors to specify a
%       uniform grid).  MYQUIVER automatically scales the velocity
%       vectors to fit within the grid.
%
%       MYQUIVER(U,V) plots the velocity vectors at equally spaced
%       points in the x-y plane.
%
%       MYQUIVER(X,Y,S) or MYQUIVER(X,Y,U,V,S,...) automatically scales
%       the velocity vectors to fit within the grid and then multiplies
%       them by S.  Use S=0 to plot the velocity vectors without the
%       automatic scaling.
%
%       MYQUIVER(...,STYLE) uses the plot linestyle specified by the string
%       STYLE for the velocity vectors.  See PLOT for other linestyles.
%
%       H = MYQUIVER(...) returns a vector of line handles.
%
%       Example:
%          [x,y] = meshgrid(-2:.2:2,-1:.15:1);
%          z = x .* exp(-x.^2 - y.^2); [px,py] = gradient(z,.2,.15);
%          contour(x,y,z), hold on
%          myquiver(x,y,px,py), hold off, axis image
%
%       See also: FEATHER, PLOT, QUIVER

%       Clay M. Thompson 3-3-94
%       Copyright (c) 1994 by The MathWorks, Inc.
%       $Revision: 1.1.4.1 $

% modified D Menemenlis 28 mar 95
% modified from QUIVER for more consistent scaling
% search for "modified" in text for details

error(nargchk(2,6,nargin));

% Arrow head parameters
alpha = 0.33; % Size of arrow head relative to the length of the vector
beta = 0.33;  % Width of the base of the arrow head relative to the length
autoscale = 1; % Autoscale if ~= 0 then scale by this.

% Check numeric input arguments
if nargin<4 
  [msg,x,y,u,v] = xyzchk(arg1,arg2);
elseif nargin==4
  if isstr(arg4)
    [msg,x,y,u,v] = xyzchk(arg1,arg2);
  else
    [msg,x,y,u,v] = xyzchk(arg1,arg2,arg3,arg4);
  end
else
  [msg,x,y,u,v] = xyzchk(arg1,arg2,arg3,arg4);
end
if ~isempty(msg), error(msg); end

if nargin==2, % myquiver(u,v)
  lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
elseif nargin==3, % myquiver(u,v,s) or myquiver(u,v,'style')
  if isstr(arg3),
    sym = arg3;
  else
    autoscale = arg3;
    lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
  end
elseif nargin==4,  % myquiver(x,y,u,v) or myquiver(x,y,s,'style')
  if isstr(arg4),
    autoscale = arg3;
    sym = arg4;
  else
    lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
  end
elseif nargin==5, % myquiver(x,y,u,v,s) or myquiver(x,y,u,v,'style')
  if isstr(arg5),
    sym = arg5;
  else
    autoscale = arg5;
    lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
  end
elseif nargin==6, % myquiver(x,y,u,v,s,style)
  autoscale = arg5;
  sym = arg6;
end

if autoscale, 
  % Base autoscale value on average spacing in the x and y
  % directions.  Estimate number of points in each direction as
  % either the size of the input arrays or the effective square
  % spacing if x and y are vectors.
  if min(size(x))==1, n=sqrt(prod(size(x))); m=n; else [m,n]=size(x); end

% modified D Menemenlis 28 mar 95
% replaced "n" and "m" by "(n-1)" and "(m-1)" for more consistent scaling as
% size of domain is increased
  delx = diff([min(x(find(~isnan(x)))) max(x(find(~isnan(x))))])/(n-1); 
  dely = diff([min(y(find(~isnan(y)))) max(y(find(~isnan(y))))])/(m-1);

  len = sqrt((u/delx).^2 + (v/dely).^2);
  autoscale = autoscale*0.9 / max(len(find(~isnan(len))));
  u = u*autoscale; v = v*autoscale;
end

ax = newplot;
next = lower(get(ax,'NextPlot'));
hold_state = ishold;

% Make velocity vectors
x = x(:).'; y = y(:).';
u = u(:).'; v = v(:).';

% modified D Menemenlis 28 mar 95
% added "+0*u" and "+0*v" to remove dots on plot for nans

uu = [x+0*u;x+u;NaN*ones(size(u))];
vv = [y+0*v;y+v;NaN*ones(size(u))];

h = plot(uu(:),vv(:),sym);

% Make arrow heads and plot them
hu = [x+u-alpha*(u+beta*(v+eps));x+u; ...
      x+u-alpha*(u-beta*(v+eps));NaN*ones(size(u))];
hv = [y+v-alpha*(v-beta*(u+eps));y+v; ...
      y+v-alpha*(v+beta*(u+eps));NaN*ones(size(v))];
hold on
h = [h;plot(hu(:),hv(:),sym)];

if ~hold_state, hold off, view(2); set(ax,'NextPlot',next); end

if nargout>0, hh = h; end
1	function hh = myquiver(arg1,arg2,arg3,arg4,arg5,arg6)
2	%MYQUIVER Quiver (or velocity) plot.
3	% MYQUIVER(X,Y,U,V) plots the velocity vectors with components
4	% (u,v) at the points (x,y). The matrices X,Y,U,V must all be
5	% the same size and contain the cooresponding position and
6	% velocity components (X and Y can also be vectors to specify a
7	% uniform grid). MYQUIVER automatically scales the velocity
8	% vectors to fit within the grid.
9	%
10	% MYQUIVER(U,V) plots the velocity vectors at equally spaced
11	% points in the x-y plane.
12	%
13	% MYQUIVER(X,Y,S) or MYQUIVER(X,Y,U,V,S,...) automatically scales
14	% the velocity vectors to fit within the grid and then multiplies
15	% them by S. Use S=0 to plot the velocity vectors without the
16	% automatic scaling.
17	%
18	% MYQUIVER(...,STYLE) uses the plot linestyle specified by the string
19	% STYLE for the velocity vectors. See PLOT for other linestyles.
20	%
21	% H = MYQUIVER(...) returns a vector of line handles.
22	%
23	% Example:
24	% [x,y] = meshgrid(-2:.2:2,-1:.15:1);
25	% z = x .* exp(-x.^2 - y.^2); [px,py] = gradient(z,.2,.15);
26	% contour(x,y,z), hold on
27	% myquiver(x,y,px,py), hold off, axis image
28	%
29	% See also: FEATHER, PLOT, QUIVER
30
31	% Clay M. Thompson 3-3-94
32	% Copyright (c) 1994 by The MathWorks, Inc.
33	% $Revision: 1.1.4.1 $
34
35	% modified D Menemenlis 28 mar 95
36	% modified from QUIVER for more consistent scaling
37	% search for "modified" in text for details
38
39	error(nargchk(2,6,nargin));
40
41	% Arrow head parameters
42	alpha = 0.33; % Size of arrow head relative to the length of the vector
43	beta = 0.33; % Width of the base of the arrow head relative to the length
44	autoscale = 1; % Autoscale if ~= 0 then scale by this.
45
46	% Check numeric input arguments
47	if nargin<4
48	[msg,x,y,u,v] = xyzchk(arg1,arg2);
49	elseif nargin==4
50	if isstr(arg4)
51	[msg,x,y,u,v] = xyzchk(arg1,arg2);
52	else
53	[msg,x,y,u,v] = xyzchk(arg1,arg2,arg3,arg4);
54	end
55	else
56	[msg,x,y,u,v] = xyzchk(arg1,arg2,arg3,arg4);
57	end
58	if ~isempty(msg), error(msg); end
59
60	if nargin==2, % myquiver(u,v)
61	lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
62	elseif nargin==3, % myquiver(u,v,s) or myquiver(u,v,'style')
63	if isstr(arg3),
64	sym = arg3;
65	else
66	autoscale = arg3;
67	lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
68	end
69	elseif nargin==4, % myquiver(x,y,u,v) or myquiver(x,y,s,'style')
70	if isstr(arg4),
71	autoscale = arg3;
72	sym = arg4;
73	else
74	lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
75	end
76	elseif nargin==5, % myquiver(x,y,u,v,s) or myquiver(x,y,u,v,'style')
77	if isstr(arg5),
78	sym = arg5;
79	else
80	autoscale = arg5;
81	lo = get(gca,'LineStyleOrder'); sym = lo(1,:);
82	end
83	elseif nargin==6, % myquiver(x,y,u,v,s,style)
84	autoscale = arg5;
85	sym = arg6;
86	end
87
88	if autoscale,
89	% Base autoscale value on average spacing in the x and y
90	% directions. Estimate number of points in each direction as
91	% either the size of the input arrays or the effective square
92	% spacing if x and y are vectors.
93	if min(size(x))==1, n=sqrt(prod(size(x))); m=n; else [m,n]=size(x); end
94
95	% modified D Menemenlis 28 mar 95
96	% replaced "n" and "m" by "(n-1)" and "(m-1)" for more consistent scaling as
97	% size of domain is increased
98	delx = diff([min(x(find(~isnan(x)))) max(x(find(~isnan(x))))])/(n-1);
99	dely = diff([min(y(find(~isnan(y)))) max(y(find(~isnan(y))))])/(m-1);
100
101	len = sqrt((u/delx).^2 + (v/dely).^2);
102	autoscale = autoscale*0.9 / max(len(find(~isnan(len))));
103	u = uautoscale; v = vautoscale;
104	end
105
106	ax = newplot;
107	next = lower(get(ax,'NextPlot'));
108	hold_state = ishold;
109
110	% Make velocity vectors
111	x = x(:).'; y = y(:).';
112	u = u(:).'; v = v(:).';
113
114	% modified D Menemenlis 28 mar 95
115	% added "+0u" and "+0v" to remove dots on plot for nans
116
117	uu = [x+0u;x+u;NaNones(size(u))];
118	vv = [y+0v;y+v;NaNones(size(u))];
119
120	h = plot(uu(:),vv(:),sym);
121
122	% Make arrow heads and plot them
123	hu = [x+u-alpha(u+beta(v+eps));x+u; ...
124	x+u-alpha(u-beta(v+eps));NaN*ones(size(u))];
125	hv = [y+v-alpha(v-beta(u+eps));y+v; ...
126	y+v-alpha(v+beta(u+eps));NaN*ones(size(v))];
127	hold on
128	h = [h;plot(hu(:),hv(:),sym)];
129
130	if ~hold_state, hold off, view(2); set(ax,'NextPlot',next); end
131
132	if nargout>0, hh = h; end