function [v,gaps_filled,gaps_unfilled]=fillgap(u,maxgap);
% function [v,gaps_filled,gaps_unfilled]=fillgap(u,maxgap);
% fill gaps (nans) shorter than MAXGAP by linear interpolation
% gaps bigger than MAXGAP values long will not be filled
[m,n]=size(u);
u=u(:);
good=find(finite(u));
dind=diff(good);
ibound1=find(dind<=(maxgap+1)& dind>1);  
ibound=find(dind>(maxgap+1));  
gaps_filled=length(ibound1);
gaps_unfilled=length(ibound);

bind=good(ibound); %boundary between good data and bad data with gaps > maxgap
x=1:length(u);
v=interp_r(x(good),u(good),x);
v=reshape(v,m,n);
%
% mask gaps that were longer than maxgap
%
for j=1:length(bind),
  j0=bind(j)+1;
  j1=bind(j)+dind(ibound(j))-1;
  jj=j0:j1;
  v(jj)=v(jj)*NaN;
end