ncDataset.addDimension(null, aggDim);
promoteGlobalAttributes( (DatasetOuterDimension) typicalDataset);
// create aggregation coordinate variable
DataType coordType = getCoordinateType();
VariableDS joinAggCoord = new VariableDS(ncDataset, null, null, dimName, coordType, dimName, null, null);
ncDataset.addVariable(null, joinAggCoord);
joinAggCoord.setProxyReader( this);
if (isDate)
joinAggCoord.addAttribute(new ucar.nc2.Attribute(_Coordinate.AxisType, "Time"));