From Empirical Questioning to Spatiotemporal Modeling - Spatio-temporal Approaches - page 54

knowledge. The authors propose a method placing time and functional aspects at the
heart of the conception of the atoms making up the city.
2.3.2.1. Step 1: to build a coherent set of functional objects in space and time
The model underlying the construction of the city is the OH_FET model
proposed by Rodier and Saligny [ROD 10]. Recalling Peuquet's decomposition
( what, when and where ), the basic object of the database, called a historical object ,
is defined as the largest stable element with regard to the 3Ds: functional, temporal
and spatial. For example, a church will be a historical object if and only if it does
not change either form, or function in the whole of its “existence”. Otherwise, it will
be decomposed into as many elemental objects that verify these stability conditions
on all 3Ds. These historical objects are then projected on each of the three
dimensions and allow slicing each of the dimensions according to this projection,
defining what the authors call “spatial entities”, “temporal entities” and “functional
entities” (Figure 2.8). This decomposition approximates the model proposed by
Worboys [WOR 94].
Figure 2.8. From historical objects to spatial, temporal and functional
reference entities (according to [LEF 12])
2.3.2.2. Step 2: to explore the temporalities
The interesting aspect of the historical objects (HO) decomposition is to be able
to represent the usage intensity of spatial portions and to show the profound
transformations that operate on fine spatial scales.