When it comes to characterize the distribution of 'things' observed spatially and identified by their geometries and attributes, the Shannon entropy has been widely used in different domains such as ecology, regional sciences, epidemiology and image analysis. In particular, recent research has taken into account the spatial patterns derived from topological and metric properties in order to propose extensions to the measure of entropy. Based on two different approaches using either distance-ratios or co-occurrences of observed classes, the research developed in this paper introduces several new indices and explores their extensions to the spatio-temporal domains which are derived whilst investigating further their application as global and local indices. Using a multiplicative space-time integration approach either at a macro or micro-level, the approach leads to a series of spatio-temporal entropy indices including from combining co-occurrence and distances-ratios approaches. The framework developed is complementary to the spatio-temporal clustering problem, introducing a more spatial and spatio-temporal structuring perspective using several indices characterizing the distribution of several class instances in space and time. The whole approach is first illustrated on simulated data evolutions of three classes over seven time stamps. Preliminary results are discussed for a study of conflicting maritime activities in the Bay of Brest where the objective is to explore the spatio-temporal patterns exhibited by a categorical variable with six classes, each representing a conflict between two maritime activities.

Although the importance of Maritime Spatial Planning (MSP) as a concept is now acknowledged and the legal framework is in place, the task of applying it remains a delicate one. One of the keys to success is having pertinent data. Knowing how maritime uses unfold in a spatio-temporal context, and what conflicting or synergistic interactions exist between activities, is crucial. However, this information is especially hard to obtain in a marine environment. As a result this information has often been identified as the missing layer in information systems developed by maritime stakeholders. Since 2002, the Automatic Identification System (AIS) has been undergoing a major development. Allowing for real time geo-tracking and identification for equipped vessels, the data that issues from AIS data promises to map and describe certain marine human activities. After recapitulating the main characteristics of AIS and the data it provides, this article proposes to evaluate how AIS is currently used in MSP at a European level, and to concisely present a series of methods and results obtained within the framework of several operational research projects. The objective is to illustrate how the AIS data processing and analysis can produce adequate information for MSP: maritime traffic density, shipping lanes and navigation flows, hierarchical network of maritime routes, alleged fishing zones, spatio-temporal interactions between activities (potential conflicting uses or synergies). The conclusion looks in particular at the legal questions concerning the use of AIS.

International audienceThe aim of this paper is to compare different maintenance costs of ecosystem service arising from a hypothetical case of environmental damage in order to help to understand how the different ecosystem services are considered in decision making processes. Compensatory measures are aimed precisely at maintaining the level of supply of ecosystem services. According to the literature, compensatory measures like restoration are usually applied to specific ecosystem services. We used the Millennium Ecosystem Assessment (MEA) categories of ecosystem service. For each MEA category, several ecological indicators are selected, and the cost of the compensatory measures required to fulfill the goal of no net loss is assessed using the Habitat Equivalency Analysis (HEA). The results of this analysis highlight differences between compensatory measures and their associated costs depending on the category of ecosystem services targeted. Maintenance costs are high for regulating services, low for provisioning services, and more difficult to determine for cultural services (high or low depending on the indicator selected). We discuss the implications of this result, noting that it is more rational for project developers to focus their attention on provisioning services if the legal regulation of compensation is lax or if indicators relative to cultural and regulating services are not precise enough