function zn=reconfig1(zin)
% zn=reconfig1(zin) inserts a row of NaNs in drifter
% data zin to separate the different drifters. each
% drifter ends with a single row of NaNs.
% 4/7/01

% remove any initial nans
nnan=find(isnan(zin(:,1)));
zin(nnan,:)=[];
% find drifter id numbers
zin=[zin;1000*ones(1,8)];
nid=find(diff(zin(:,8))>0.01);
id=zin(nid,8);
Nid=length(id);
% form new array
rownan=nan*ones(1,8);
zn=ones(1,8);
for j=1:Nid
   m=find(zin(:,8)==id(j));
   zn=[zn;zin(m,:);rownan];
end
zn(1,:)=[];
