//
// momvdfcreate code snippet
//
{

	//
	// Initialize POP data readers
	//
	NetCDFCOllection ncdfc()
	ncdfc.Initialize(files);

	VDC vdc(VDC::NETCDF4);

	// Open the VDC master file for writing. 
	//
	status = vdc.Initialize(masterpath, "w");

	// Set up compression parameters. We will use the same ones for all
	// variables. Ditto for boundary periodicity
	//
	vdc.SetCompressionBlock(opt.bs, opt.wname, opt.wmode, opt.cratios());
	vdc.SetPeriodicBoundary(opt.periodic);

	// Get dimensions from mom files, and define them in the VDC
	// For VDC and CF files each dimension has a 1D coordinate variable 
	// associated with it. The 1D coordinate variable and the dimension
	// have the same name.
	//
	vector <string> coordvars= ncdfc.GetCoordVarsCF();
	for (int i=0; i<coordvars.size(); i++) {
		vector <size_t> dimlens = ncdfc.GetDims(coordvars[i]);
		assert(dimlens.size() == 1);	// netCDF "coord vars" are 1D

		// Figure out which axis
		//
		int axis = 0;
		if (ncdfc.IsLonCoordVar(coordvars[i])) {
			axis = 0;
		}
		else if (ncdfc.IsLatCoordVar(coordvars[i])) {
			axis = 1;
		}
		else if (ncdfc.IsVertCoordVar(coordvars[i])) {
			axis = 2;
		}
		else if (ncdfc.IsTimeCoordVar(coordvars[i])) {
			axis = 3;
		}

		vdc.DefineDimension(coordvar[i], dimlens[0], axis);
	}

	// Now get all of the mom coordinate variables with one or more
	// dimensions.
	//
	vector <string> latcoordvars = ncdfc.GetLatCoordVars();
	vector <string> loncoordvars = ncdfc.GetlonCoordVars();
	vector <string> vertcoordvars = ncdfc.GetVertCoordVars();
	vector <string> timecoordvars = ncdfc.GetTimeCoordVars();


	//
	// Define the coordinate variables in the VDC using same dimension
	// names as in the mom data set. We're lazy and we've hard-coded the units 
	// (e.g. degrees_east). Should get these from ncdfc. Also, we're
	// redefining any CF "Coordinate variables" implicitly defined by
	// DefineDimension(). We need to do this because the implicit
	// definition does defines no units.
	//
	for (int i=0; i<loncoordvars.size(); i++) {
		vector <string> dimnames = ncdfc.GetDimNames(loncoordvars[i]);

		vdc.DefineCoordVar(
			loncoordvars[i], dimnames, "degrees_east", VDC:X, 
			VDC:FLOAT32, false
		);
	}
	for (int i=0; i<latcoordvars.size(); i++) {
		vector <string> dimnames = ncdfc.GetDimNames(latcoordvars[i]);

		vdc.DefineCoordVar(
			latcoordvars[i], dimnames, "degrees_north", VDC:Y, 
			VDC:FLOAT32, false
		);
	}

	for (int i=0; i<vertcoordvars.size(); i++) {
		vector <string> dimnames = ncdfc.GetDimNames(vertcoordvars[i]);

		vdc.DefineCoordVar(
			vertcoordvars[i], dimnames, "meters", VDC:Z, 
			VDC:FLOAT32, false
		);
	}

	for (int i=0; i<timecoordvars.size(); i++) {
		vector <string> dimnames = ncdfc.GetDimNames(timecoordvars[i]);

		vdc.DefineCoordVar(
			timecoordvars[i], dimnames, "seconds", VDC:T, 
			VDC:FLOAT32, false
		);
	}




	//
	// Find all of the 3d variables in the mom data set and define them
	// in the VDC
	//
	vector <string> vars = ncdfc.GetVariableNames(3);
	for (int i=0; i<vars; i++) {
		vector <string> dimnames = ncdfc.GetDimNames(vars[i]);
		vector <string> coordvars;
		ncdfc.GetVarCoordVarNames(vars[i], coordvars);

		mysort(coordvars);	// coordinate varibles in VDC must be ordered

		string units;
		ncdfc.GetVarUnits(vars[i], units);

		vdc.DefineDataVar(
			vars[i], dimnames, coordvars, units, VDC::FLOAT32, true
		);
	}

	vdc.EndDefine();
		

	//
	// now copy all of the coordinate variables from the mom files
	// to the VDC. We use the time hyperslice version of PutVar()
	// to ensure the data volumes aren't too large. This is 
	// because we're assuming MOM and POP coordinate variables
	// have at most 2 spatial dimensions. If they could be 3D we'd
	// want to something that uses less memory
	//
	float *data;
	for (int i=0; i<coordvars.size(); i++) {
		string cvar = coordvars[i];
		vector <size_t> dims = ncdfc.GetDims(cvar);

		// make sure 'data' is big enouth
		//
		data = reallocate_if_needed(data, dims);	
		
		size_t numts = ncdf.GetNumTimeSteps();

		for (size_t ts = 0; ts<numts; ts++) {
			ncdfc.OpenRead(ts, cvar);
			ncdfc.Read(data);
			ncdfc.Close();

			vdc.PutVar(ts, data);
		}
	}

}