Improving the planning of public facilities: Considering the spatio-temporal distribution of population

Updated and detailed mapping of population distribution is important for decision support in a variety of fields, such as emergency management, transportation planning, land planning, GeoMarketing, and environmental studies. Such data sets can be useful for virtually any application involving the spatial distribution of people if they are produced at appropriate, application-specific, spatial and temporal scales [1]. Having this information in a GIS-usable raster format significantly increases its value and facilitates integration with other spatial datasets for analysis or modeling. Although efforts to rasterize population distributions predate the development of most commercial GIS packages [2], increased availability of digital spatial data combined with the improved analysis capabilities in GIS have allowed for the development of several global population distribution databases. However, their spatial detail is still insufficient to adequately support analysis at the local level and to distinguish between daytime and nighttime population distributions. Population distributions are not static in time, varying over daily, seasonal and long term time scales [1]. Due to a number of human activities, such as work and leisure, population counts and their distribution vary widely from nighttime to daytime, especially in metropolitan areas, and may be misrepresented by census data. Data mining combined with dasymetric mapping allows re-distributing population to specific areas where it is present in more detailed temporal periods, by using ancillary data and zonal interpolation.