if exist('n')~=1
  error('need to assign value for n')
end
if exist('e')~=1
  error('need to assign value for e')
end
if exist('s')~=1
  error('need to assign value for s')
end

% make an example data set
[x,y,z] = peaks;
pcolor(x,y,z)
cax = caxis;
colorbar
shading flat

% sample it at set of user defined points
switch opt
  case 'ginput'
    [xd,yd] = ginput(n);
  case 'rand'
    xd = 6*(rand([n 1])-0.5);
    yd = 6*(rand([n 1])-0.5);
  otherwise
    error('need to choose a method for selecting test data')
end

hold on
plot(xd,yd,'ko')

% make some data with errors
dd = interp2(x,y,z,xd,yd) + e*randn(size(xd));
scatter(xd,yd,30,dd,'filled')
caxis(cax)

% map the data with griddata
zg = griddata(xd,yd,dd,x,y);
 
% map the data with loess filter
% s = 10;
zl = loess2dg(xd,yd,dd,x,y,s,'distance');

clf
subplot(121)
pcolor(x,y,z)
hold on
cax = caxis;colorbar;shading flat
plot(xd,yd,'ko')
scatter(xd,yd,30,dd,'filled')
caxis(cax)

subplot(122)
pcolor(x,y,zl)
caxis(cax)
hold on
colorbar;shading flat
plot(xd,yd,'ko')
scatter(xd,yd,30,dd,'filled')
caxis(cax)