Location–allocation models applied to urban public services. Spatial analysis of Primary Health Care Centers in the city of Luján, Argentina 387 Hungarian Geographical Bulletin 62 (4) (2013) 387–408. Location–allocation models applied to urban public services. Spatial analysis of Primary Health Care Centers in the city of Luján, Argentina Gustavo BUZAI1 Abstract The actual digital technologies and particularly the association between the Geographical Information Systems (GIS) and the assistance to the Spatial Decision Support System (SDSS) have generated important possibilities for the treatment of spatial information. As regards the use of location-allocation models, this presentation assesses the possibilities of using such models in the fi eld of the geography of services. In this paper theoretical aspects of the analyzed problems are presented, as well as methodological standardized questions for their solution through the use of GIS+SDSS. An applied case study related to the spatial analysis of Primary Health Care Centers (PHCC) in the city of Lujan, Argentina is also presented. Keywords: Spatial analysis, location-allocation models, primary health care centres, GIS, SDSS. Introduction The application of geographical analysis procedures, oriented towards service planning, is actually presented as a very dynamic fi eld of investigation starting from the use of Geographical Information Systems (GIS) as well as the Spatial Decision Support Systems (SDSS). The models of higher application were defi ned from a conceptual and practical view some four decades ago (Revelle, Ch. and Swain, R. 1970; Austin, C. 1974; McAllister, D. 1976) and during the decade of 1990 this in- formation slowly spread throughout the digitalization fi eld, through soft ware intended to support decision-making. Digital standardization of procedures has evolved along with socio- economic aspects in population´s basic services diversifi cation as in the ap- 1 Study Group on Geography and Spatial Analysis with GIS (GESIG), Geographical Studies Program (PROEG), National University of Luján. Ruta Nacional No 5 y Av. Constitución, 6700 Luján, Argentina. E-mail: gesig-proeg@unlu.edu.ar; web: www.gesig-proeg.com.ar 388 pearance of a post-fordist model in which small and medium enterprises (SMEs) supplying services to the industry and other enterprises have an im- portant role. In view of the above, the spatial location of services appeared to be of a great importance in many aspects, particularly in the fi eld of public services, and in att empts to improve the levels of spatial equity for the population to be served. Along these lines, the present work may be considered as a later stage for spatial data exploration and has as a principal objective to set forth a stand- ardization of the theoretical methodological aspects of spatial localization in order to prioritize, from a geographical perspective, the process of decision making at the moment of installing, relocating or increasing a given number of installations of public urban services. The application implemented here will be centered on the spatial localization of the PHCCs in the city of Luján, Argentina (34°34´13´´S and 59°06´18´´ W), with a population of 78,500 in 2012 (Municipalidad de Luján, 2012). Effi cient and equitable access to public services must be guaranteed. Theoretical background Location-allocation models Geographical studies have a broad tradition in the generation of theories and general models for the analysis of human activities. Particularly, as regards the tertiary activities, it is possible to consider the theory of central places proposed by Walter Christaller in 1933 as a model of optimum spatial localization of urban centres at a regional level. In its formulation, the concepts of threshold and reach are presented as a deductive basis from which we can explain certain empiric regularities that were presented in the systematization carried out by Beavon, K. (1980). From a model-based view, the localizations (potential supply and de- mand points), the distances (ideal or real) and the costs of displacements (spatial friction) are presented as the principal factors that produce diff erent territorial confi gurations in the system. A series of studies focuses on the terti- ary activity and as regards evolution, goes forward in a change of scale from the analysis of urban centres (regional) towards the inside centres of the city (local). This materializes in the geography of marketing, a concept presented by Berry, B. (1971) having been widely analyzed in its current capacities by a series of authors (Moreno-Jiménez, A. 1995, 2004; Bosque-Sendra, J. 2004; Bosque-Sendra, J. and Moreno-Jiménez, A. 2004; Salado-García, M. 2004; Moreno-Jiménez, A. and Buzai, G. eds. 2008). 389 From this point of view, the theory of localization takes into consid- eration problems in the installation of services and generates a double objec- tive: on the one hand to fi nd the optimum localizations, and on the other to determine the allocation of demand for such centres. To resolve this double objective models of allocation-localization have been developed. According to Ramírez, L. and Bosque-Sendra, J. (2001), the location- allocation models meet the following characteristics: a) they are mathematical models since this language is considered appropriate to capture reality; b) they are spatial models at intermediate scale because the aspects to be solved are already delimited in a territory; and c) they are normative models because it is necessary to look for the best solution to a given problem. In synthesis those models att empt to assess the actual locations of service centres on a demand distribution basis, and to generate alternatives to achieve a more effi cient and/or equitable spatial distribution. Those models are designed to fi nd the optimum localizations and determine the best links of the demand (allocation). In recent years the application of location-allocation models, even those operationalized based on a Geographical Information Systems basis, have been framed in a specifi c system called Spatial Decision Support System (SDSS).2 According to Bosque-Sendra, J. et al. (2000), the SDSS’s principal objective is to supply a necessary environment in hardware and soft ware to facilitate us- ers in spatial decision-making matt ers. In this sense, the study of exploration problems, the generation of various solutions and the evaluation of diff erent alternatives need to be assessed. . Densham, P. (1991) presents two well diff erentiated levels as regards the application of SDSS, one in which the user takes decisions through gener- ating, evaluating and choosing solution alternatives, and the system interface achieving a multidirectional interaction between the data base and its pos- sibilities for making numerical and graphical reports. Finally, it must be noted that location-allocation models are very use- ful methodologies to support decision-making for health care in developing countries (Rahman, S. and Smith, D. 2000). 2 Decision Support Systems (DSS) were initially developed in the economic and management sciences during the 1950s and 1960s and were widely diff used during the next two decades. Likewise, the concept of Spatial Decision Support Systems (SDSS) was developed at the same time, being the Geodata Analysis and Display Systems (GADS) developed by IBM (International Business Machines) during the 1970s. Since the second half of the 1980s, DSS have begun to be adopted as tools for the enlargement of the technology capacity GIS. Some aspects of this process were developed by Malczewski, J. (1998). 390 Orientation of the location-allocation From a general point of view, the orientation supplied for the model of loca- tion-allocation, will be infl uenced by the nature of the service. If the service is private, it will basically focus on improving spatial effi ciency, on the other hand, if it is public, it will try to improve spatial equity. Both refer to the enhancement of global parameters for the access to the service: the sum of the total displace- ments, accessibility values or diff erences among extreme values. Similarly, a notorious diff erence is shown if the equipment to be in- stalled is desired (benefi cial) or not desired (prejudicial). While the fi rst ones basically generate positive externalities (hospitals, schools, cultural centres etc.) the second ones generate negative externalities (cemeteries, jails, rubbish dumps, etc.). Therefore, taking in to account the previous considerations, the SDSS will contemplate diff erent possibilities of methodological application according to the objective in charge of fi nding the localization of the service centres. Methodology Searching for candidate sites and their combinations The application of location-allocation models implies having an off er, distrib- uted in a point manner, and a demand which, for reasons of simplifi cation, may be assigned to a centroid of each area and a transport network linking them. However, the application of methods att empt to fi nd new supply loca- tions must fi rst consider the determination of possible candidate sites, that is to say a quantity of selected points with the purpose of selecting the best one(s) according to the applied model objective. There are two basic possibilities for the consideration of candidate sites: a) obtain them through procedures of thematic superposition and multi- criteria evaluation (MCE) techniques, and b) consider each centroid of demand as a possible site for the installation. The MCE techniques were extensively developed in Buzai, G. and Baxendale, C. (2011) and the use of the centroids of areas as candidate sites was studied methodologically by Fotheringham, A. et al. (1995). The second technique appears to be linked with the modifi able area unit problem (MAUP) at the moment in which a variation in the number of spatial units will allow possible modifi cation of the results obtained. Therefore, avoiding the necessity of assessing the infi nite localizations, the models work with the combinations of p centres in n candidates points, being p> /ColorImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000ColorACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000ColorImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /GrayImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000GrayACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000GrayImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict << /K -1 >> /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile (None) /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False /CreateJDFFile false /Description << /ARA /BGR /CHS /CHT /CZE /DAN /DEU /ESP /ETI /FRA /GRE /HEB /HRV (Za stvaranje Adobe PDF dokumenata najpogodnijih za visokokvalitetni ispis prije tiskanja koristite ove postavke. 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