MATLAB: Filling the area between two open ended curves

fill open are between lines

I want to fill the area between the curves as shown in the attached picture. I tried fliplr and flipud, it does not work. Also I tried the below function and it still gives me a wrong output.

function val=area_col(fname)
p=load(fname);
x=p(:,1);
y1=p(:,2);
y2=p(:,3);
fx=[x x(end:0:1)];
fy=[y1 y2(end:0:1)];
figure
hold on
plot(x,y1);
plot(x,y2);
fill_color=[.929 .694 .125];
fh=fill(fx,fy,fill_color);
hold off

Thank you very much for any support.

Best Answer

Try this:

p = load('L_D copy.txt');
x  = p(:,1);
y1 = p(:,2);
y2 = p(:,3);
figure
plot(x, y1,    x, y2)
hold on
fill_color=[.929 .694 .125];
patch([x; flipud(x)], [y1; flipud(y2)], fill_color)
hold off

producing:

Related Solutions

MATLAB: Adjusting plot fill to show two colours depending on overestimation/underestimation

Have a look at http://www.mathworks.com/matlabcentral/fileexchange/34876--greater-than--fill

or my solution that does need no interpolation but computes the intersection points.

function fillline(x, y1, y2, col1, col2) 
% Thorsten Hansen 2015-05-02 2014-11-27
% See also
% http://www.mathworks.com/matlabcentral/fileexchange/34876--greater-than--fill
if nargin < 3
  x = -10:10;
  y1 = sin(x);
  y2 = cos(x);
end
if nargin < 5
  col1 = [1 0 0];
  col2 = [0 0 1];
end
hold on
colpatch(y1 >= y2, col1, x, y1, y2)
colpatch(y2 >= y1, col2, x, y1, y2)
plot(x, y1, '-', 'Color', col1)
plot(x, y2, '-', 'Color', col2)
hold off
function colpatch(ind, col, x, y1, y2)
% special case 1: all values of y2 below y1: nothing to fill
if ~any(ind)
  return
end
% define fill color as a lighter version of the color on the line above
col = lighten(col);
% force row vectors for proper concatenation in fill below
x = x(:)'; y1 = y1(:)'; y2 = y2(:)'; ind = ind(:)';
% special case 2: no intersections, all values of y2 above y1
if all(ind)
  fill([x x(end) fliplr(x) x(1)], ...
       [y1 y1(end) fliplr(y2) y2(1)], col, 'EdgeColor', col);
  return
end
% general case: y1 and y2 intersect
val = cumsum(diff([0 ind]) == 1).*ind;
v = 1;
ind = find(val == v);
while ~isempty(ind)
  xi = x(ind); y1i = y1(ind); y2i = y2(ind); 
    % determine intersections to fill area between intersections
    % determine left intercept
    ii = ind(1);
    if ii > 1
      line1 = [x(ii) y1(ii); x(ii-1) y1(ii-1)];
      line2 = [x(ii) y2(ii); x(ii-1) y2(ii-1)];
      [xis_left yis_left] = lineintercept(line1, line2);
    else
      xis_left = [];
      yis_left = [];
    end
    % determine right intercept
    ii = ind(end);
    if ii < numel(x) 
      line1 = [x(ii) y1(ii); x(ii+1) y1(ii+1)];
      line2 = [x(ii) y2(ii); x(ii+1) y2(ii+1)];
      [xis_right yis_right] = lineintercept(line1, line2);
    else
      xis_right = [];
      yis_right = [];
    end
    % add patch
    fill([xis_left xi xis_right fliplr(xi)], ...
         [yis_left y1i yis_right fliplr(y2i)], col, 'EdgeColor', col);
    %set(h), pause
    v = v + 1; % next patch
    ind = find(val == v); % indices of next patch
  end
function [xis  yis] = lineintercept(line1, line2)
slope = @(line) (line(2,2) - line(1,2))/(line(2,1) - line(1,1));
m1 = slope(line1);
m2 = slope(line2);
intercept = @(line,m) line(1,2) - m*line(1,1);
b1 = intercept(line1,m1);
b2 = intercept(line2,m2);
% intersection
xis = (b2-b1)/(m1-m2);
yis = m1*xis + b1;
%plot(xis,yis,'ko','MarkerSize',10)
function col = lighten(col)
col = col + 0.8*([1 1 1] - col);

MATLAB: Fill the region between two lines

Use the patch (link) function:

x=0:0.1:10;
y1=exp(-x/2);
y2=exp(-x/3);
figure
hold all
plot(x,y1)
plot(x,y2)
patch([x fliplr(x)], [y1 fliplr(y2)], 'g')
hold off

To use it, create a closed area (the reason for the fliplr calls, since they create the closed area), and choose the color.

Best Answer

Related Solutions

MATLAB: Adjusting plot fill to show two colours depending on overestima​​tion/unde​r​estimati​on

MATLAB: Fill the region between two lines

Related Question

MATLAB: Adjusting plot fill to show two colours depending on overestimation/underestimation