combine a mesh and some node data to produce a field
combine_mesh_data combines a mesh and some node data. A Node_Data object represents the values of some dataset at the node points of a field, while the Mesh represents the locations of that field's nodes in space.
This macro simplifies the process of generating field data by reducing the amount of data you must supply to create a field. Usually this macro is used to combine the output of a mesh mapper with the output of one or more data mappers.