Using GIS and Geocoded Health Facility Databases to Develop Primary Care Catchment Area Policy in Urban Settings

Abstract

Primary healthcare catchment areas in Thailand are commonly defined based on administrative boundaries, which may not reflect actual accessibility through transportation networks. This study aimed to assess the consistency between administratively assigned service areas based on household registration and spatial accessibility to healthcare services, and to examine whether these patterns correspond with actual service utilization. This study employed a spatial analytical design using Geographic Information Systems (GIS). Six villages in Pang Mu Subdistrict, Mae Hong Son Province, Thailand, were purposively selected as case studies. Data sources included diabetes patient registry records to identify village locations, geographic coordinates of health facilities collected through field surveys using a portable Global Positioning System (GPS), official records of village boundaries and assigned service areas, road network data from government agencies, and healthcare utilization statistics from the previous 12 months. Spatial analysis was conducted using QGIS version 3.40.15 and the QNEAT3 plugin to calculate network-based service areas. A distance threshold of 2,500 meters (approximately five minutes of travel time) was applied to estimate accessible service areas along the road network. The results were then compared with administrative service boundaries and actual healthcare utilization patterns. The findings revealed that all six sampled villages were located outside the five-minute network-based service area of their administratively assigned primary healthcare facilities. Service utilization patterns also differed from the official administrative boundaries, indicating a mismatch between administrative catchment definitions and real-world geographic accessibility. These findings highlight the importance of integrating spatial analysis with healthcare utilization data in defining primary healthcare service areas and underscore the need for a national database of health facilities with standardized geographic coordinates to support spatially informed health service planning.