Organizing data by a named property such as region:
group USA {
group Colorado {
dimensions: time = unlimited, stations = 47;
variables: float temperature(time, stations);
}
group Wyoming{
dimensions: time = unlimited, stations = 61;
variables: float temperature(time, stations);
}
group Alaska {
dimensions: time = unlimited, stations = 53;
variables: float temperature(time, stations);
}
...
dimensions: time = unlimited;
variables: float average_temperature(time);
}