Documentation of map_contour

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Function Synopsis

[c, h] = map_contour(data, cint, line_style);

Help text

  [c, h] = map_contour(data, cint, line_style);

  data = map data
  cint:     if scalar, then it's the contour interval
            if vector, then it's a vector of contours levels
  line_style = common line styles (see plot)

  This function uses the mapping toolbox to contour the
  input 'data' matrix.  It assumes that the x and y axes
  are defined in the global variables XAX and YAX, 
  respectively.

Cross-Reference Information

Listing of function map_contour

function [c, h] = map_contour(data, cint, line_style);

%  Dan Vimont, 2 September, 1999

if nargin < 3; line_style = '-k'; end;
if nargin < 2; cint = (max(max(data))-min(min(data)))/10; end;

data = squeeze(data);

%  First, determine if hold is 'on', or 'off'.

next_ax = lower(get(gca, 'NextPlot'));
if strcmp(next_ax, 'replace');  cla;  end;

%  Get the global varaibles XAX YAX and FRAME

global XAX YAX FRAME
if (size(XAX, 1) == 1); XAX = XAX'; end;
if (size(YAX, 1) == 1); YAX = YAX'; end;

[m, n] = size(data);
if or((m~=length(YAX)), (n~=length(XAX)));
  error('[length(YAX) length(XAX)] must equal size(data)');
end

%  Redefine XAX, YAX and data for global contouring -- allowing 
%  for wrapping around the globe.

[xk, yk] = keep_var(FRAME, XAX, YAX);
if (FRAME(2) - FRAME(1) == 360);
  data2 = [data(yk,:) data(yk,1)];
  XAX2 = [XAX; XAX(1)+360];
else
  data2 = data(yk,xk);
  XAX2 = XAX(xk);
end;
YAX2 = YAX(yk);

%  Define contour interval;

if isscalar(cint);
  clev = sort([-cint:-cint:min(min(data2)) ...
                0:cint:max(max(data2))]);
else
  clev = cint;
end

%  Plot the data

ver = version;
if strcmp(ver(1), '6');
  [c, h] = contourm(YAX2, XAX2, data2, clev, line_style);
elseif strcmp(ver(1), '5');
  [c, h] = contorm(YAX2, XAX2, data2, clev, line_style);
end;

set(gca, 'NextPlot', next_ax);