function [data] = nldnc_timestep(ncobj,varName,t)
% function [data] = nldnc_timestep(ncobj,varName,t)
%
% Inputs:
%		ncobj   :  a netcdf file object created  with command
%                 netcdf(filename, 'nowrite')
%              where filename is the name of the file from dbconv
%   varName :  variable name to load eg: 'TEMPERATURE'
%   t       :  timetsep to load
% Outputs
%		data    : a matlab structure that contains the data from the timestep
%             and the relevant dimensions.
%
% Uses:
%
% Written by C. Dallimore 19 Jan 06
%


% Get variable object
ncVar = ncobj{varName};

if isempty(ncVar)
	data = [];
	disp ('Variable not found.  Valid variables are')
	variables=var(ncobj);
	for i = 1:length(variables)
		self = variables{i};
		theNCid = ncid(self);
		theVarid = varid(self);
		[dimName, dimSize] = ncmex('varinq', theNCid, theVarid);
		disp(['  ',dimName])
	end
	return
end

% Get dimensions of variable
vardims = dim(ncVar);

% varcmd is the command we will run to load this timestep
% it depends on which dimension T is
varcmd = sprintf('data.data = ncVar (',char(varName));

for i = 1:length(vardims)

	self = vardims{i};
	theNCid = ncid(self);
	theDimid = dimid(self);
	[dimName, dimSize] = ncmex('diminq', theNCid, theDimid);
	dimVar = ncobj{dimName};

	if (strcmp(dimName,'T'))
		if (t > dimSize)
			data = [];
			disp ('Timestep out of range')
			return
		end
		cmd = sprintf('data.%s = dimVar (t);',char(dimName));
		eval(cmd);
		dimName = 'Ordinal_Dates';
		dimVar = ncobj{dimName};
		cmd = sprintf('data.%s = dimVar (t);',char(dimName));
		eval(cmd);
		tindex = i;
		varcmd = [varcmd,'t'];
	else
		cmd = sprintf('data.%s = dimVar (:);',char(dimName));
		eval(cmd);
		varcmd = [varcmd,':'];
	end
	if i ~= length(vardims)
		varcmd = [varcmd,','];
	else
		varcmd = [varcmd,');'];
	end
end

eval(varcmd);

pts = find(data.data < -9.9e+16);
data.data(pts)=NaN;