The world is organised according to large territorial areas and structured by exchange and information networks in which cities are the main junction points. Our goal is to analyse the processes which lead to changes in the main territorial and spatial configurations at this scale by avoiding to restrict ourselves to the established divisions of the world. We especially try to demonstrate how main spatial units and delineations emerge from the observation of multiple networks of interactions (material, financial, cognitive…), on the long term as well as for more recent periods.
The second line of investigation is organised around three main areas:
The construction of harmonised databases in different regions of the world and for long time scales, based on generic models and automatised methods enriched by experts. First of all, this is the case for the database on European cities (Urban Morphological Zones) which is also related to a study on the construction of functional urban areas around UMZ centers, based on empirical data (minimal level of commuting) and on the delineation of one-hour isochrons (maximal time-budget for commuters). A complementary study deals with the characterisation of urban forms through a series of statistical indicators, whether these UMZ are monocentric, polycentric, dense or sprawled out. Second of all, it is also the case for the databases of systems of cities in India, China, Russia, Brazil and South Africa, including the information on financial flows produced according to the Orbis database studied at the University of Lausanne. Finally, it is the case for a database on the spaces of scientific productions which are similar on a global scale.
The formalisation of city dynamics using processes of complex systems with three main objectives.
The aim is to consolidate a scalable theory of systems of cities by confronting the generic processes of their dynamics to historical and territorial specificities which inflected their evolution in different parts of the world. According to us, these models, studied in collaboration with the Institute of Complex Systems, summarise knowledge and “stylised facts“ that can be used to build the simulation models as found in our third line of research, experiment alternatives aimed at testing the hypotheses and theories made for the purposes of this analysis. We also attempt to analyse urban networks and systems of cities according to different time scales in terms of important divisions which have punctuated transformations since the Neolithic age. We work with computer engineers, linguists, archeologists, historians, epistemologists and mathematicians to offer a formalisation of these significant transitions and of the underlying social and spatial processes. Finally, we examine the resilience of maritime networks and port-territory relationships to big contemporary changes (technological, political, economical…) at different geographical levels, urban or continental, through an analysis of the worldwide flows of merchant vessels since the 18th century.
The analysis of the regeneration of relational spaces according to specialised flows (scientific collaborations, sea trade, possibly media exchanges or cognitive ties...) to develop a critical approach to state or continental analytical frameworks and to bring out new topological proximities.
We suggest a hypothetic-deductive approach where we can, both at once, use the segmentations of the World as variables that explain the organisation of networks and flows and, from the residues of interaction models, deduce the existence of underlying territorial structures that do not necessarily coincide with usual territorial frameworks. In both cases, we adopt a historical approach to understand how these systems recompose themselves.
Finally, the analysis recently carried out on the perception of places judged attractive and repulsive by students from 18 countries in the world provides us with another example of the interest for an approach in terms of networks rather than in terms of stocks in the case of textual analysis. The results of this survey will be compared to an analysis of the way in which the media reports international events. In both cases, we will model the flows of geographical knowledge conveyed by the media, either through a study of programmes (the RSS feeds of newspapers), or through the analysis of receivers and cognitive filters (students’ mental maps).
The second line of research is based on a series of groups and projects of cross-disciplinary research:
• the group Espon M4D
• the European Research Council Advanced Grant project Geodivercity develops models which represent the dynamics of systems of cities in different parts of the world (Europe, United-States, India, China, Russia, Brazil, South Africa) (with computer engineers from the Ile-de-France Institute of Complex Systems).
• the European Research Council Starting Grant project World Seastems maps and analyses worldwide flows of merchant vessels based on the Lloyd’s List database
• Institute of Complex Systems