Exploiting available data sources: location/allocation modeling for health service planning in rural Ghana

The preconditions for applying GIS-based location-allocation analysis for health service planning in rural Ghana are examined in terms of data availability and quality. A population map is established from the latest available census using geo-coding methods and digital topographic sheets. A vector-based transport model of the region is established by merging data from several sources including GPS. It is suggested that a hybrid transport model is required. This model combines the possibilities for all-direction transportation inherent in the raster-based approach with the possibilities for road/path transportation inherent in the vector-based approach. All-direction movements are expected to take place close to the villages in order to reach a suitable linear transport corridor represented by a vector. Several scenarios for improving the accessibility aspects of the health service provision are examined in light of Ghana's current health service policy. Location-allocation modelling tools are used to select optimal locations and provide statistics on average distance to health centres and percentage of population covered.     

UAV-borne,LiDAR-based elevation modelling: a method for improving local-scale urban flood risk assessment

Natural Hazards - In this study, we present the first findings of the potential utility of miniaturized light and detection ranging (LiDAR) scanners mounted on unmanned aerial vehicles (UAVs) for...     

Large-area urban growth observations—a hierarchical kernel approach based on image texture

Geografisk Tidsskrift, Danish Journal of Geography 105(2):39–47, 2005

A multi-scale classification algorithm based entirely on computation of image texture in moving windows is presented and discussed. The rationale for using kernel-based methods as opposed to segment-based methods for texture-based land cover classification is discussed, as well as, the need for identifying strategies that may limit the effects of the inherent weaknesses of the kernel-based methods. Part of the proposed solution to this problem is to omit the search for an optimum kernel size and rather use different sizes concurrently followed by a weighted summary overlay process based on associated scores. The spatial growth pattern of the city of Accra, Ghana, is assessed over a 17 years period using the algorithm. Land-cover maps showing the extension of the new residential areas on the fringe of Accra are produced from Landsat ETM satellite imagery. These areas constitute the rapidly expanding frontier of urban Accra into its rural surroundings. The classification discriminates between new residential areas that have a distinct urban appearance and areas that are in a transition phase between rural and urban use. Finally, comparisons are made to a previous satellite-based study of land cover changes for the period 1985–1991.