||Chardy Pierre, Glemarec M., Laurec A.
||Estuarine and Coastal Marine Science (Elsevier), 1976 , Vol. 4 , P. 179-205
||The various so-called inertia methods, the aim of which is to summarize the relationships between points by a configuration of reduced dimension, may all be considered variants of a more general method. In this regard, the links existing between Principal Component Analysis, Principal Coordinates Analysis and the Analysis of Correspondences appear clearly. Three fundamental options (inherent in all inertia methods) determine the divergences among these techniques: choice of distance, choice of weights attributed to the points, choice of position of the origin. This viewpoint also shows up the relationships between the analysis of the R and Q matrices of one and the same set of data. The application of these techniques to data of the benthic bionomy of the North Gascony continental shelf illustrates the ecological implications of the three possible theoretical choices. Analysis of the differences observed at the level of the structures obtained produces an overall ecological interpretation that one method taken in isolation could not reveal. [NOT CONTROLLED OCR]