Doctor of Philosophy / Department of Biological & Agricultural Engineering / Kyle R. Douglas-Mankin / Water quality trading (WQT) is a market-based approach to improve water quality. It is an innovative, voluntary program that connects point source (PS) dischargers who need to reduce their pollutant loads with land managers who could offset those loads with nonpoint source (NPS) reductions to economically achieve water quality improvements in a watershed. The potential issues impeding WQT are its inability to address trading risks and quantify the uncertainty of potential load reduction in trades between PS and NPS. Recent research has also shown that trading information level and transaction costs cause problems in implementing WQT. Therefore, the goals of this study were to quantify the uncertainties of pollutant load reduction and delivery effect for potential trades, to estimate their spatiotemporal variations, and to provide information for stakeholders to reduce intangible costs of WQT. This study simulated agricultural cropland with more than 225 alternative land management practices to identify trends among these scenarios. Both total nitrogen and total phosphorus loads were modeled with SWAT and EUTROMOD for 36 years to analyze the potential load reduction, in-field uncertainty ratio, in-stream delivery ratio, and overall trading ratio (TR) in Lower Kansas watershed, Kansas. The analyses of site-specific effects in both geospatial and temporal aspects were also applied on subbasin level. The variant loading patterns and time distributions of each subbasin showed strong site-specific phenomena. The ANOVA of in-field nutrient load showed significant differences among the design criteria of scenarios. The results also showed a significant delivery and lake effects within the subbasins. The overall TR ranged from 1 to 2.2 or more in different scenarios. The advanced cluster analysis presented a potential method to eliminate the problems involved in fixed TRs while keeping the method simpler than finer-resolution floating TR system. Based on WQT geospatial data model, a three-tier GIS-based web interface Water Quality Trading Information Platform System (WQTIPS) was then developed for WQT information and assessment. A case study demonstrated WQTIPS can provide systematic, spatially information for stakeholders to assess the potential environmental benefit changes from the land management shifts using a simple interface. This study demonstrated that it is possible to automate water-quality trades, use watershed models to minimize trading risk and maximize water-quality benefits, and prioritize among possible trades both spatially and by BMP.

Access to clean water and improved sanitation are basic human right. This quantitative, descriptive study sought to establish current water and sanitation coverage in Chirumanzu and Shurugwi districts in Zimbabwe and develop methods of assessing coverage using Geographic Information Systems. Google Earth was used to identify homesteads. Personal digital assistant-based forms were used to collect geo-referenced data on all water points and selected households. Geospatial analysis methods were used to calculate borehole water coverage. Using Google Earth, 29375 homesteads were identified. The water survey mapped 4134 water points; 821 were boreholes; and only 548 were functional. Functional borehole water coverage was: 57.3%, 46.2%, and 33.5% for distance from household to water point of within 1500 m, 1000 m, and 500 m respectively. Sanitation coverage was 44.3%, but 96% of the latrines did not meet Blair Ventilated Pit latrine standards. / Health Studies / M.A. (Public Health) (Medical Informatics)

Στην παρούσα εργασία γίνεται μια προσπάθεια ανάδειξης του φαινομένου των κατολισθήσεων στο Νομό Αχαΐας με κύρια συνιστώσα το χρόνο (παρελθόν - παρόν- μέλλον). Οι κατολισθήσεις αποτελούν ένα σημαντικό φυσικό κίνδυνο (Natural Hazard) καθώς είναι ευρέως διαδεδομένες και κατέχουν μία θέση στη λίστα των λεγόμενων Φυσικών Καταστροφών (Natural Disasters). Έχει παρατηρηθεί ότι στη Δυτική Ελλάδα τα φαινόμενα των κατολισθήσεων είναι περισσότερα και συχνότερα απ’ ότι στη κεντρική και ανατολική Ελλάδα, κυρίως λόγω της λιθολογικής σύστασης των σχηματισμών, της έντονης και ενεργής τεκτονικής καθώς και των υψηλών βροχοπτώσεων. Ο Ν. Αχαΐας είναι μία από τις πιο χαρακτηριστικές περιοχές μελέτης κατολισθήσεων καθότι εκτός της μεγάλης συχνότητας του φαινομένου, υπάρχει μεγάλη ποικιλία ως προς την έκφρασή του (γεωλογία, μέγεθος, αίτια, συνέπειες κα). Εδώ και δεκαετίες, από το Εργαστήριο Τεχνικής Γεωλογίας του Τμήματος Γεωλογίας Πανεπιστημίου Πατρών, μελετώνται τα φαινόμενα κατολισθήσεων στο Νομό οπότε υπάρχει αρκετός όγκος πληροφόρησης που μας δίνει στοιχεία για το παρελθόν μέσω των υφιστάμενων Βάσεων Δεδομένων. Σήμερα, παρόν, υπάρχει σχετικά άμεση ανταπόκριση και αντιμετώπιση των φαινομένων και καλύτερη καταγραφή αυτών. Το ερώτημα που τίθεται είναι κατά πόσο είναι εφικτό παρακολουθώντας και καταγράφοντας την ενεργότητα των κατολισθήσεων, να προβλέψουμε μία μελλοντική εξέλιξή τους, μέλλον. Για τον σκοπό αυτόν έγινε μία διεξοδική συλλογή στοιχείων και ανάπτυξη μιας νέας Βάσης Δεδομένων Κατολισθήσεων για το Ν. Αχαΐας. Αρχικά, αναπτύχθηκε μία Φόρμα Καταγραφής Κατολισθήσεων (Landslide Inventory Form) στην οποία καταγράφηκαν 123 περιπτώσεις για την Αχαΐα (ιστορικές καταγραφές), από τις οποίες διατηρήθηκε ένα μέρος. Έγινε προσπάθεια αναγνώρισης και αποτύπωσης των καταγεγραμμένων θέσεων με χρήση Γεωγραφικών Συστημάτων Πληροφόρησης - ΓΠΣ (Geographical Information System – GIS). Η αποτύπωση έγινε με την βοήθεια ορθοφωτοχαρτών της ΚΤΗΜΑΤΟΛΟΓΙΟ ΑΕ και κατά περιπτώσεις σαν βοηθητικό εργαλείο του GoogleEarth. Παράλληλα με τις παλαιές (ιστορικές) θέσεις αναγνωρίστηκαν μία σειρά επιπλέον κατολισθήσεων (νέες) οι οποίες αποτέλεσαν μία σειρά νέων καταγραφών. Προέκυψε έτσι μία αρκετά ενημερωμένη Βάση Κατολισθήσεων η οποία και αναρτήθηκε στο Διαδίκτυο στον ιστότοπο του Εργαστηρίου Τεχνικής Γεωλογίας. Από τις θέσεις που καταγράφηκαν τελικά επιλέχθηκαν οι τέσσερις (4) πλέον σημαντικές και «ενεργές» κατολισθήσεις μερικές από τις οποίες έχουν απασχολήσει αρκετά επιστήμονες και τεχνικούς τα παλαιότερα χρόνια, για περαιτέρω παρακολούθηση (monitoring) με ενόργανο εξοπλισμό (αποκλισιόμετρο) και μεθόδους τηλεπισκόπισης (remote sensing - SAR interferometry). Οι θέσεις αυτές είναι: (α) η κατολισθαίνουσα ζώνη Πλατάνου, (β) η κατολίσθηση της Παναγοπούλας, (γ) η κατολίσθηση της Καρυάς και (δ) η κατολίσθηση στον οικισμό Πλατανίτη Ναυπάκτου του Νομού Αιτωλοακαρνανίας. Στις θέσεις αυτές έγινε λεπτομερής γεωτεχνική έρευνα και εγκατάσταση αποκλισιομετρικών σωλήνων για συστηματική παρακολούθηση της κινηματικής και την ανάπτυξη ενός μοντέλου επικινδυνότητας. / The objective of this thesis is the study of landslide hazard. It’s an attempt to highlight the phenomenon of landslides in the Prefecture of Achaia function of time (past - present - future). Landslides constitute a major geologic hazard because they are widespread and we can add them in the hall of fame of natural disasters. It has been observed that in western Greece phenomena of landslides are more frequent than in the central and eastern Greece, mainly due to the lithology of the formations, the strong and active tectonics and high rainfall. For decades, the Laboratory of Engineering Geology, Department of Geology, University of Patras, studied the effects of landslides in the Prefecture, as a result, there is enough volume of data that gives us information about the past through the existing Database. Today, there is immediate response and handling of landslide phenomena as well as better recording methods. The question that arises is whether it is possible by monitoring and recording the activity of landslides to predict a future evolution, future. For this purpose took place a detailed collection of data and developed a new landslide database for the Prefecture of Achaia. At first, we developed a Landslide Inventory Form which recorded and archived 123 historical cases from Achaia, a part of that study was recorded and kept for further study. After that, the landslide recordings were imported to the Geographical Information Systems - GIS. Additionally, we used orthophotos from KTIMATOLOGIO S.A. and occasionally we used, as an auxiliary tool GoogleEarth. Alongside with the old (historical) landslide sites we identified a series of additional landslides (new ones) which helped us constitute a new archive with new recordings. As a result, there is an updated Landslide Database which was published on the webpage of the Laboratory of Engineering Geology. From this point of view, we selected the four (4) most important and "active" landslides from which some of them have been the major study of several scientists and technicians in the past. Further monitoring (monitoring) with instrumental equipment (inclinometer) and remote sensing methods (remote sensing - SAR interferometry) was used in the study. These positions are as recorded : (a) the landslide zone at Platanos area (b) the landslide of Panagopoula area, (c) the landslide of Karia village and (d) the landslide at Platanitis area, near Nafpaktos village, Aitoloakarnania Prefecture. On these studies, a detailed geotechnical investigation and installation of inclinometer tubes for systematic monitoring of the kinematics and the development of a risk model was used.

Σκοπός της παρούσας εργασίας, είναι η διερεύνηση των υδροχημικών παραμέτρων των κοκκωδών υδροφόρων της λεκάνης του Σπερχειού, καθώς και η πιθανή τροφοδοσία τους από τα ανθρακικά πετρώματα. Για το σκοπό αυτό πραγματοποιήθηκαν μετρήσεις στάθμης, καθώς και υδροχημικές αναλύσεις κύριων στοιχείων, ιχνοστοιχείων και σπάνιων γαιών. Γεωλογικά η περιοχή, στο βορειοανατολικό και νοτιοανατολικό τμήμα της ,δομείται από τους σχηματισμούς της Υποπελαγονικής ζώνης, στο νότιο από τους σχηματισμούς της ζώνης Παρνασσού-Γκιώνας και στο δυτικό από τους σχηματισμούς της ζώνης της Πίνδου. Οι Ολοκαινικές και Πλειο-πλειστοκαινικές αποθέσεις, δομούν το πεδινό τμήμα της λεκάνης και φιλοξενούν τον κύριο υδροφόρο ορίζοντα της περιοχής. Ο ελεύθερος αυτός υδροφόρος μεταπίπτει σε υπό πίεση, εξαιτίας της παρουσίας αργιλικών σχηματισμών, στα ανατολικά της περιοχής. Στα ορεινά τμήματα της λεκάνης, εντός των ανθρακικών σχηματισμών, αναπτύσσονται σημαντικοί υδροφόροι ορίζοντες. Με βάση τον πιεζομετρικό χάρτη της περιοχής προκύπτει ότι η διεύθυνση της ροής του υπόγειου νερού, είναι κυρίως ΒΑ-ΝΑ και o προσχωματικός υδροφόρος, τροφοδοτείται πλευρικά, από τους ανθρακικούς σχηματισμούς, που βρίσκονται νότια και βορειοανατολικά του πεδινού τμήματος. Τα υπόγεια νερά της περιοχής, ομαδοποιούνται σε τρεις κύριους υδροχημικούς τύπους: Ca-HCO3, Ca-Mg-HCO3 και (Ca)-Νa-Cl-(HCO3). Ο πρώτος υδροχημικός τύπος χαρακτηρίζει τα φρέσκα νερά της περιοχής, ο δεύτερος τα νερά που παρέμειναν για μεγαλύτερο χρονικό διάστημα στον υδροφόρο και εμπλουτίστηκαν σε Μg+2, και ο τρίτος τα νερά που δέχονται την επίδραση είτε της θάλασσας, είτε των θερμών νερών από μεγαλύτερα βάθη. Από τα αποτελέσματα των υδροχημικών αναλύσεων προέκυψε ότι στην πλειοψηφία τους τα δείγματα είναι κορεσμένα σε ασβεστίτη και δολομίτη. Eπίσης σε μία ομάδα δειγμάτων, διαπιστώθηκε απεμπλουτισμός σε Na, γεγονός που αποδόθηκε σε διαδικασίες ιοντοανταλαγής. Οι αυξημένες συγκεντρώσεις Fe, Mn, αποδόθηκαν στη διάλυση των ορυκτών του φλύσχη της Πίνδου, ενώ ο Zn και τα NΟ3 σε ανθρωπογενείς παρεμβάσεις (βιομηχανικά απόβλητα και λιπάσματα). Το As το Li και το Β συνδέονται με την παρουσία θερμών πηγών. Τέλος η μεθοδολογία των σπάνιων γαιών, επαλήθευσε τα αποτελέσματα της πιεζομετρίας αλλά και τα υδροχημικών αναλύσεων, ότι δηλαδή ο προσχωματικός υδροφόρος της περιοχής, τροφοδοτείται πλευρικά από τα ανθρακικά πετρώματα της περιοχής και συγκεκριμένα από τους ασβεστόλιθους της Υποπελαγονικής ζώνης και της ζώνης Παρνασσού-Γκιώνας. / In the frames of this study the hydrochemical parameters of porous aquifers at Sperchios basin, were investigated. Moreover their possible recharge by carbonate rocks was examined. Therefore, a series of water level measurements and a sampling campaign were carried out. The samples were analysed for main, trace and rare earth elements. Regarding the area’s geological setting, its northeastern and southeastern part is comprised of formations of the Subpelagonic Zone, its southern edge of Parnassos-Giona Zone and its western part of Pindos Zone. At the lowlands these formations are overlain by Holocene and Pleistocene deposits which host the most important aquifer of the region. It is an unconfined aquifer, which at the eastern part turns into a confined one, due to the presence of clay formations. Many important aquifers have been also developed in the basin’s carbonate formations. The region’s piezometric map at the southern area indicates that the main water flow direction is NE-SE. Moreover it points out that the carbonate formations recharge the porous aquifer. According to their hydrochemical characteristics groundwater can be divided into three main types: Ca-HCO3, Ca-Mg-HCO3 and (Ca)-Na-Cl-(HCO3). The first one is typical of the region’s fresh water, the second one indicates longer residence time of the water that was enriched in Mg+2 and the third one of water that was either influenced by sea water or hot springs. The elaboration of the hydrochemical data also showed that the majority of water samples are saturated in calcite and dolomite. There is also a depletion of certain samples in Na+ which was attributed to ion exchange processes. High Fe and Mn concentrations originate from the dissolution of Pindos Flysch minerals, As, Li and B to the presence of hot springs, while Zn and NO3 were related to human impact (industrial waste and fertilizers). The rare earth elements confirmed the original hypothesis, which was based on piezometric data and hydrochemical data analysis, that the region’s porous aquifer is laterally recharged by the carbonate rock formations of Subpelagonic and Parnassos-Giona Zone limestones.

The purpose of this study is to assist TxDOT engineers in the field of traffic control planning. This is to be done via the creation of a Geographic Information System (GIS) based tool. By bringing together information about TxDOT’s on-system roadways’ geographical locations, traffic demands, and capacities, one aggregate database has been established. Using the tools of GIS, Microsoft Excel, Microsoft Access, and VBA programming, a static clickable interface has been constructed. It enables users to access properties for any selected roadway link they desire. Expansion of the product to ArcIMS is ongoing to allow easy access for end users via the internet. / text

Hedonic pricing methods and GIS (Geographic Information Systems) were used to evaluate relationships between sale price of single family homes and landscape fragmentation and natural land cover. Spatial regression analyses found that sale prices increase as landscapes become less fragmented and the amount of natural land cover around a home increases. The projected growth in population and employment in the Richmond, Virginia region and subsequent increases in land development and landscape fragmentation presents a challenge to sustaining intact healthy ecosystems in the Richmond region. Spatial regression analyses helped illuminate how land cover patterns influence sale prices and landscape patterns that are economically and ecologically advantageous.

Geospatial data almost always contains some amount of uncertainty due to inaccuracies in its acquisition and transformation. While the data is commonly visualized (e.g. on digital maps), there are unanswered needs for visualizing uncertainty along with it. Most research on effectively doing this addresses uncertainty in data values at geospatial positions, e.g. water depth, human population, or land-cover classification. Uncertainty in the data’s geospatial positions themselves (positional uncertainty) has not been previously focused on in this regard. In this thesis, techniques were created for visualizing positional uncertainty using World Vector Shoreline as an example dataset. The techniques consist of a shoreline buffer zone to which visual effects such as gradients, transparency, and randomized dots were applied. They are viewed interactively via Web Map Service (WMS). In clutter testing with human subjects, a transparency-gradient technique performed the best, followed by a solid-fill technique, with a dots-density-gradient technique performing worst.

La ville africaine est marquée par un dualisme du modèle urbain. A côté de la ville moderne, administrée, équipée, " légale ", se développent les quartiers " illégaux ", sans équipements ni services urbains de base. La Côte d'Ivoire n'échappe pas à cette situation. Au lendemain des indépendances, elle entreprend la plus vaste opération de géographie volontaire en vue de réduire les injustices spatiales et les inégalités entre régions du Sud forestier ; « l'opération San-Pedro ». Objectif: mettre en valeur une région jusqu'alors totalement enclavée et en marge du « miracle économique ivoirien » ; le Sud-ouest du pays avec comme point d'ancrage, la création d'un port en eau profonde et d'une ville nouvelle. Malgré un projet d'urbanisme largement concerté, San-Pedro abrite aujourd'hui l'un des plus grands quartiers précaires de l'Afrique de l'ouest, favorisant ainsi une fragmentation de plus en plus accentuée de la ville. On observe aujourd'hui dans la ville, moins de 10% des occupations immobilières ayant faits l'objet d'un enregistrement cadastral et d'un droit foncier réel inattaquable. Ce faible pourcentage illustre l'échec du système de l'immatriculation foncière, seule voie légale de sécurisation foncière et immobilière. Cela pose la question fondamentale d'autres voies alternatives à la sécurisation foncière et immobilière. D'où le nécessaire développement des systèmes d'adressage qui, à l'absence de cadastre général, permet de localiser les parcelles à partir de l'espace public afin d'améliorer la connaissance du patrimoine immobilier c'est-à-dire assurer une identification publique des biens et des droits existants facilitant ainsi leur sécurisation et leur reconnaissance juridique ultérieure. A cet effet, de nombreux pays africains ont lancé ces dernières années, des opérations d'adressage visant à servir d'alternative au cadastre fiscal et aux projets difficiles et lents de « régularisation foncière » en promouvant des formes simplifiées et principalement littérales d'identification des parcelles.Cette thèse vise donc à établir à San-Pedro, l'intérêt de l'utilisation d'un système d'adressage dans les politiques de sécurisation foncière et immobilière. Elle cherche à comprendre les relations entre l'adressage et le "droit à la ville", c'est-à-dire le droit d'accès aux ressources urbaines notamment d'accès à la propriété et à la sécurité du logement. Pour appréhender ces relations, il s'avère nécessaire d'entreprendre l'analyse sous l'angle de la justice spatiale tout en soulignant l'importance de l'adressage comme outil de reconnaissance des droits fonciers locaux et surtout d'intégration sociale et économique des populations.Cette approche ouvre de nouvelles perspectives méthodologiques à exploiter dans la réforme des systèmes fonciers et cadastraux des pays africains. / The African city is marked by a dualism of urban model. Alongside the modern city, administered equipped "legal" grow "illegal" areas, no equipment or basic urban services. Côte d'Ivoire is no exception to this. After independence, she undertook the largest operation of voluntary geography to reduce spatial injustices and inequalities between regions of southern forest; "Operation San Pedro." Objective: To develop a region until completely enclosed and outside the "Ivorian economic miracle", the South-west of the country with as an anchor, creating a deep water port and a new city . Despite a largely collaborative project planning, San Pedro now houses one of the largest shantytowns of West Africa, thereby promoting fragmentation increasingly accentuated the city. We observe today in the city, less than 10% of real estate occupations having made the subject of a land registration and real property of an indefeasible right. This low percentage shows the failure of the system of land registration, the only legal way of land and property security. This raises the fundamental question of alternative ways to land and property security. Where necessary the development of addressing systems, the lack of general survey, used to locate plots from public space to improve the knowledge of the real estate that is to say, ensure public identification of property and existing rights and facilitating their security and their subsequent legal recognition. To this end, many African countries have launched in recent years, addressing operations to serve as an alternative to fiscal cadastre and slow and difficult projects "land regularization" promoting simplified forms and mostly literal identification plots.Therefore this thesis aims to establish in San Pedro, the interest of the use of an addressing system in the policies of land and property security. It seeks to understand the relationship between the address and the "right to the city", that is to say, the right of access to urban resources including homeownership and housing security. To understand these relationships, it is necessary to undertake an analysis in terms of spatial justice while emphasizing the importance of addressing as a tool for recognition of local land rights, especially social and economic integration populations.This approach opens new methodological perspectives to operate in the reform of land tenure and cadastral African

Propõe-se a aplicação de técnicas do geoprocessamento, por meio do Sistema de Informações Geográficas, à problemática da regularização fundiária e urbanística de favelas; com o objetivo de facilitar, agilizar e ampliar o conhecimento de instituições públicas sobre estas áreas irregulares, apoiando-as em suas decisões. A proposta foi aplicada ao Município de Taboão da Serra, e a área piloto estudada foi a favela Jardim Santo Onofre. Vários materiais e procedimentos técnicos foram apresentados nesta pesquisa como: o uso de imagens aéreas, a pesquisa sobre a situação de registro em cartório da área, a realização da pesquisa sócio-econômica, o levantamento topográfico e a realização de análises espaciais - no intuito de identificar com segurança o tipo de irregularidade presente e quais os procedimentos corretos para regularizar a terra e a situação urbanística local. Também foi apresentada a aplicabilidade do Sistema de Informações Geográficas à gestão de projetos urbanísticos e como mecanismo para ampliar as chances de sucesso do programa de regularização. O aumento da agilidade do processo de regularização e a melhoria na qualidade das análises e caracterização da área favelada são os principais resultados esperados com a aplicação desta proposta, que fez uso de dados reais e hipotéticos para gerar demonstrações da aplicabilidade do geoprocessamento. / The proposition of this study is the application of geoprocessing techniques, through geographic information systems, to slums urban and land regulation problematic. The objective of this purpose is to make easier and faster and to enlarge the public institutions knowledge about those irregular places, helping and supporting them on their decisions. This purpose was applied to Taboão da Serra town and the studied area was a slum named Jardim Santo Onofre. Many different material and technical procedures were presented here as aerial images use, research about registry offices documents, social and economical stages, topographic studies and spatial analysis everything with the intention of identify the kind of existent irregularity and the correct procedures to regulate the land and local urban situation. It also presented the GIS applicability to the management of urban project and as a mechanism to enlarge the success chances of regulation process. The improvement of regulations agility, of the analysis quality and of the slums characterization studies are the most important expected results of this proposition and its application. This masters degree text is based on real and hypothetic data to prove the geoprocessing application.

A distância e o tempo de viagem são elementos de importância para a avaliação do acesso aos serviços de saúde, esta é uma questão que para a população do campo tem uma importância especial devido às particularidades geográficas do espaço rural. A presente pesquisa tem como objetivo desenvolver uma metodologia de mapeamento da rede de rodovias rurais com indicações de impedâncias de viagem, utilizando-se para isso dos Sistemas de Informação Geográfica (SIG) e tendo em vista a otimização do traslado da população rural aos serviços de saúde. A orientação teórica se apóia no conceito de distância na Geografia e em concepções sobre a medida da acessibilidade e mobilidade espacial. Faz-se uma ampla observação das abordagens e metodologias voltadas ao estudo da acessibilidade geográfica das populações rurais aos serviços de saúde, sobretudo, as que tratam de fatores espaciais e fazem uso dos SIG. Dados relativos às classes de rodovias rurais, declividade da paisagem, sinuosidade, visibilidade e uso da terra, são considerados na composição de uma síntese de impedâncias. A avaliação toma como parâmetro o tempo de viagem por veículo automotor e as medidas se fazem com base na rede rodoviária ponderada por impedâncias. A população rural e as unidades de atendimento à saúde são os referencias para a avaliação da acessibilidade geográfica. A metodologia foi aplicada à Microrregião de Registro (SP) e os resultados indicam que a velocidade nos percursos muda de acordo com os atributos associados às rodovias, sendo as estradas locais nãopavimentadas as que apresentam maior variabilidade para a geração de condições ótimas de viagem. A distribuição espacial dos serviços de saúde reflete na acessibilidade geográfica e algumas regiões são mais penalizadas no acesso aos serviços hospitalares. O modelo aqui apresentado orienta à montagem de um SIG para a análise da acessibilidade da população rural aos postos de saúde e hospitais e atende a duas principais aplicações: (i) o apoio ao planejamento da viagem da população rural aos postos de atendimento à saúde; (ii) e auxílio em facilitar o acesso da população rural às consultas e atendimento de ocorrências emergenciais, pela aplicação de recursos de análise de rede, tais como: caminho mínimo, matriz de origens-destinos e área de serviço. Ambas as aplicações poderão resultar num melhoramento do planejamento das áreas de influencia dos centros de saúde na região rural. / Distance and travel time are important parameters in the evaluation of access to health services. For the population living in the countryside, this has become a significant issue due to geographical particularities of rural areas. The objective of this work is the development of a GIS-based methodology for the mapping of rural road networks and the determination of travel impedances in order to optimize the travel time of the rural population to health care facilities. The theoretical orientation is based on the concept of geographical distance and on the conception of the extent of accessibility and mobility. A general overview is given of approaches and methodologies which study the geographical accessibility of health services facilities by the rural population with particular consideration of those which deal with spatial factors and make use of GIS (Geographic Information System). Data on rural roads classes, slope, sinuosity, visibility and land use are considered in the composition of the impedances synthesis. The evaluation uses the travel time by car as a parameter, and the quantifications are based on the road network with velocities adjusted by the impedances. This way, network distances, velocity and the travel time are the criteria for the evaluation of the geographical accessibility to health care facilities by the rural population. The methodology was applied to the Region of Registro (SP), and the results indicate that the velocity on the particular road sections changes depending on the attributes associated with the road classes with the observation that unpaved roads represent the worst conditions for establishing optimum travel conditions. The distribution of health service facilities is reflected in the geographical accessibility, and some regions are highly penalized regarding access to hospital services. The model presented here points out methods for the installation of a GIS for the analysis of the accessibility of health care facilities by the rural population with respect to the following applications: (i) support of the rural population when planning journeys to health care facilities; (ii) improved access to medical examination and emergency assistance by analysis of the network, i.e., by determining the minimum traveling distance, the origin-destination matrix and the service areas of the health care facilities. Both applications may improve covering and planning rural health service facilities.