La Rochelle, France knew during the second half of the twentieth century an important increase of its permanent and seasonal population. Since 1999, the city is grouped together with 17 others municipalities (communes) into an intercommunality (cooperation group between communes) : La Rochelle's community of Agglomeration (CDA-LR) (fig 1). Because of an attractive coastal position, the CDA-LR is subjected to a strong growing of population. It showed itself by a massive urban spread. This urban spread is constrained by a coastal position (physical constraints and planning regulations). This urban spread is today particularly visible in the peripheral municipalities (Communes) of the CDA-LR. These municipalities absorb the inhabitants because they cannot find a housing in the city of La Rochelle. The CDA-LR is under a strong land pressure because of its attractive coastal position. The land is very regulated and the built is already very dense. Inhabitants are thrown back towards the peripheral by the price of the housing. The mastery of the urban spreading of the CDA-LR is one of stakes of the future land development plan (schema de coherence territorial : SCOT). The SCOT is at present in progress. The aim of this paper is to propose space and time analysis tools in order to study the urban spread phenomenon. These tools are implemented in a geographical information system. Cadastral dataset is used as an input.