What is meant by locational data and attribute data?
This is probably easier to explain for object-based models: locational data define the location of the spatial objects (e.g. houses, administrative areas), whereas the attribute data provide information on the properties of these objects (e.g. who lives in the house, how many people live in the administrative area). Multiple attribute values may be associated with each object defined by the locational data in a object-based model using a relational join to join an attribute table to the spatial objects. These objects are normally defined in vector mode, but they may also be defined in raster mode (e.g. each cell in a raster could be allocated a code to identify the administrative area in which the cell is located; these identifier codes might then be used as the join field with an attribute data table). In a field-based model, the attribute data refer to the property which varies over space (e.g. altitude, rainfall), whereas the locational data indicates the location of these measures.
