The Assessment and Mapping of Urban Visual Pollution through an Assembly of Open Source Geospatial Tools

Urban surroundings and spaces are losing their identity due to the visual pollution in the urban panorama of already densely populated cities in the developing countries. Quantitative assessment of visual pollution and its spatial mapping are very recent and relatively un-explored branches of urban studies. The diversity of visual pollution objects (VPOs) and their traits, the subjectivity of observers, the scale of urban space and dependency on subjective variables are the key challenges for quantification during visual pollution assessment (VPA). A paper-based score-card type VPA tool using Analytical Hierarchy Process to address these issues has previously been developed. However, considering the challenges associated with the deployment of paper-based tool for VPA (which include the inability to handle variety of data types such as text, numeric, geolocation, images, etc.), the natural progression is the development of a mobile-based solution which matches the fast-growing mobile penetration rate of urban centres and provides a turn-key solution to achieve efficiency and effectiveness in primary data collection. On the other hand, academic research on the spatial mapping of visual pollution has slightly progressed to explore its cartographic dimension. This research presents a spatial decision support system comprising of a combination of open source tools to collect, store and present VPA data for any urban space of any scale. The system employs Open Data Kit (ODK) to build its mobile-based VPA tool which can be used to collect VPO attributes using any Android device. The collected data is streamed to a web-based data management module of the system in real time which is built upon ODK Aggregate and PostgreSQL. Furthermore, the web-based visualisation module of the system is built upon some other major open source tools including OpenGeo Suite and PHP. The visualisation module presents the results of visual pollution index (VPI) in the form of a web-based dashboard containing real-time choropleth maps which can be filtered for any specific VPO. This research demonstrates the strengths of open geospatial tools to solve challenges of primary data collection on a diverse range of VPOs along with the systematic capturing of their spatial location and visual images. Furthermore, it proves the ability of open source web mapping tools to display visual pollution assessments in most appropriate cartographic representation. Resultantly, it offers the practitioner urban planners a tested mechanism to assess and map the levels of urban visual pollution in an urban space and help them take effective measures to improve the visual image of the city.