Geographic Health Mapping for Sickle Cell Disease Programs

Spatial Health Data Concepts

Geographic health mapping — also known as spatial epidemiology — applies geographic information science to public health. By linking health outcomes to locations, spatial analysis reveals patterns invisible in tabular data: disease clusters, underserved areas, facility coverage gaps, and environmental-health relationships. For SCD programs, mapping enables visualization of disease prevalence at the community level, reveals gaps in facility coverage, supports field agent deployment planning, and enables spatial analysis of program performance.

Geographic Hierarchies

Health data is organized within hierarchies reflecting administrative structures. These enable aggregation or disaggregation at different resolutions. Tracka implements a six-level hierarchy: Country, State/Province, Local Government Area/District, Ward, Community, and Health Facility. Each patient record is associated with a specific location, enabling analysis at any aggregation level. This structure accommodates different country administrative arrangements while maintaining a consistent analytical framework.

Nigeria's Administrative Structure

Nigeria comprises 36 states plus the FCT, 774 LGAs, and approximately 9,572 wards. Health service delivery is primarily the responsibility of LGAs (primary care) and states (secondary/tertiary care). Disease prevalence, infrastructure, and program capacity vary enormously — states like Lagos and Kano have developed infrastructure while many northern states face severe access challenges. LGA-level analysis reveals even greater variation.

Tracka's geographic database contains the complete Nigerian administrative hierarchy with geospatial coordinates, enabling precise mapping and cascading geographic filters in analytics dashboards — from national overview to state, LGA, ward, and facility level views.

Mapping Tools and Technologies

Relevant technologies include QGIS for desktop spatial analysis, Leaflet and Mapbox GL for web-based interactive maps, DHIS2's built-in geographic modules, and satellite imagery from Google Earth Engine. For SCD specifically, mapping tools should support patient distribution by genotype and severity, facility coverage analysis with travel time calculations, field agent catchment area mapping, temporal analysis of disease burden evolution, and export of maps for reports and policy briefs.

Use Cases for SCD Programs

Coverage gap analysis identifies communities with high estimated prevalence but low screening or enrollment. Facility planning uses travel time analysis for optimal clinic placement. Outbreak response enables rapid identification of complication clusters indicating environmental triggers. Resource allocation uses spatial patient density and severity analysis for equitable distribution of medications, supplies, and specialist services. Tracka integrates geographic visualization throughout — from individual patient records to program dashboards — ensuring geographic equity remains central to resource allocation and service delivery planning.