Documentation of color_shade_dave

Global Index (short | long) | Local contents | Local Index (short | long)

Function Synopsis

[hout, cout] = greyshd(XAX, YAX, aray, level, colr);

Help text

  [h, c] = color_shade(x, y, dat, lev, color)

  This function shades in areas where the function x is 
  greater than the value 'lev'.  Note that lev MUST be 
  a scalar, so this isn't like contourf.  This is all done
  for a map axis.

Cross-Reference Information

Listing of function color_shade_dave

function [hout, cout] = greyshd(XAX, YAX, aray, level, colr);

if ~isscalar(level);
     error('level must be a scalar');
end

if ismap(gca);
     error('This function works for non-map axes only.  Try greyshd for non-map axes.');
end

%global XAX YAX FRAME
FRAME = [0 0 0 0];
FRAME(1:2) = get(gca, 'XLim');
FRAME(3:4) = get(gca, 'YLim');

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

[xk, yk] = keep_var(FRAME, XAX, YAX);

if (FRAME(2)-FRAME(1) == 360); 
  aray2 = [aray(yk,:) aray(yk,1)];
  XAX2 = [XAX; (XAX(1)+360)];
  YAX2 = YAX(yk);
else
  aray2 = aray(yk,xk);
  XAX2 = XAX(xk);
  YAX2 = YAX(yk);
end

[nlat, nlon] = size(aray2);

%  Now, surround the matrix by low values so the contours are closed
%  (This is in case lev is near or equal to the minimum of aray)

aray2 = [repmat(NaN,1,(nlon+2)) ; repmat(NaN,nlat,1) aray2 repmat(NaN,nlat,1) ;...
         repmat(NaN,1,(nlon+2))];
aind = find(isnan(aray2));
aray2(aind) = (level - 1000) * ones(size(aind));

XAX2 = [2*XAX2(1,:)-XAX2(2,:); XAX2; 2*XAX2(nlon,:)-XAX2(nlon-1,:)];
YAX2 = [2*YAX2(1,:)-YAX2(2,:);   YAX2 ; 2*YAX2(nlat,:)-YAX(nlat-1,:)];

[CS, msg] = contours(XAX2, YAX2, aray2, [level max(max(aray2+1))]);
if ~isempty(msg); error(msg); end;

% Find the indices of the curves in the c matrix, and get the
% area of closed curves in order to draw patches correctly.  This
% shouldn't matter... might be able to delete this...

ii = 1;
ncurves = 0;
I = [];
Area=[];

while (ii < size(CS,2)),
  nl=CS(2,ii);
  ncurves = ncurves + 1;
  I(ncurves) = ii;
  xp=CS(1,ii+(1:nl));  % First patch
  yp=CS(2,ii+(1:nl));
  Area(ncurves)=sum( diff(xp).*(yp(1:nl-1)+yp(2:nl))/2 );
  ii = ii + nl + 1;
end

% Plot patches in order of decreasing size. This makes sure that
% all the leves get drawn, not matter if we are going up a hill or
% down into a hole. When going down we shift levels though, you can
% tell whether we are going up or down by checking the sign of the
% area (since curves are oriented so that the high side is always
% the same side). Lowest curve is largest and encloses higher data
% always.

H=[];
[FA,IA]=sort(-abs(Area));

if ~isstr(get(gca,'color')),
  bg = get(gca,'color');
else
  bg = get(gcf,'color');
end

%colr = [.9 .9 .9];
for jj=IA,
  nl=CS(2,I(jj));
  lev=CS(1,I(jj));

    xp=CS(1,I(jj)+(1:nl));  
    yp=CS(2,I(jj)+(1:nl)); 

%    if (sign(Area(jj)) ~= sign(Area(IA(1))) ),
%      kk=find(nv==lev);
%      if (kk>1+sum(nv<=minz)*(~draw_min)), 
%        lev=nv(kk-1);
%      else 
%        lev=NaN;         % missing data section
%      end;
%    end;

  if (isfinite(lev))
    H=[H;patch(xp,yp,lev-100*ones(size(xp)), colr, 'facecolor',colr,'edgecolor',colr,'linestyle','-')];
  else
    H=[H;patch(xp,yp,lev-100*ones(size(xp)), colr, 'facecolor',bg,'edgecolor',bg,'linestyle','-')];
  end;

end;


numPatches = length(H);
if numPatches>1
  for i=1:numPatches
    set(H(i), 'faceoffsetfactor', 0,...
        'faceoffsetbias', (1e-3)+(numPatches-i)/(numPatches-1)/30, ...
        'Clipping', 'off'); 
  end
end

if nargout>0, 
  % Return contour matrix for unfilled contours
%  cout=contours(x,y,z,nv);
  cout = CS;
  hout = H;
end