For some fields, there is a number for each point in space. They are called "scalar fields". For more complicated fields, there are more than one number for each point in space. They are called "vector fields" or "tensor fields". For example, one can model a gravitational field by a vector field where a vector indicates the acceleration a mass would experience at each point in space. Other examples are temperature fields or air pressure fields, which are often illustrated on weather reports by isotherms and isobars by joining up the points of equal temperature or pressure respectively.