24 ©Department of Geography. Valahia University of Targoviste Annals of Valahia University of Targoviste. Geographical Series Tome 12/2012 Issues 1-2: 24-29 http://fsu.valahia.ro/avutgs/home.html DETERMINATION OF THE AREA OF INFLUENCE OF PLOIEŞTI CITY IN THE URBAN SYSTEM OF PRAHOVA COUNTY Monica Carmen CATANĂ 1 , Adrian Aurel BALTALUNGA 2 Technological High School “1 Mai” Ploieşti 2 Valahia University Târgovişte Résumé La motivation de la réalisation de l’étude présente a été donnée par la multitude d es notions et des acceptions rencontrées au niveau des autorités locales et régionales ou dans divers travaux de spécialité concernant la sphère d’influence, respectivement de coopération ou de complémentarité directe de la ville de Ploieşti. Le but de ce matériel est de contribuer à cet aspect, en le clarifiant, et aussi d’intégrer la ville de Ploieşti dans son contexte départemental, utilisant la même méthodologie (la formule Reilly-Converse) en double sens, à savoir essayant de déterminer aussi la sphère d’influence des autres villes faisant partie du système urbain du département de Prahova par rapport au siège de cette unité territoriale, la ville de Ploieşti. En même temps, on a appliqué aussi la même méthode de détermination concernant les centres politiques-administratifs des départements voisins. Mots clé: villes, population, sphère d’influence, zone métropolitaine, pôle de croissance, types de relations, distances. I. Theoretical-methodological considerations The determination of the area of influence of the towns/cities represents an intensely discussed, analysed and sometimes even controversial issue, which has preoccupied the specialists of different domains even since the 19 th century. This is natural, seeing the particular theoretical and practical importance of such an approach, starting from political-administrative reasons to economic, social and demographic aspects. This explains the various definitions and synonyms present in the specialized literature and normative acts. The term is defined in the Romanian legislation as well by the Law no. 351 / July 6, 2001 on the approval of the National Territory Arrangement Plan - Section IV – Locality network. In Annex no. 1 – Definition of the main terms used – at point (14) it is written: “Area/Sphere of influence – territory and localities surrounding an urban area and directly influenced by the evolution of the town/city and the interconditioning and cooperation relations developed along the line of the economic activities, of the food supply, of the access to social and trading facilities, of the endowment with infrastructure, recreational and tourist facilities. The dimensions of the sphere of influence are directly connected to the size and functions of the polarizing urban centre”. Important for this topic is also point (11), defining the term of metropolitan area – “area built through association, based on voluntary partnership, between large urban centres (Romania’s capital and its first rank county seats) and the urban and rural localities situated in its vicinity, at distances of up to 30 km, between which cooperation relations have developed on different levels.” At the same time,