Sunday, 16 October 2016

Fuzzy Geographically Weighted Clustering

Mason G.A., and Jacobson, R.D. (2007) Fuzzy Geographically Weighted Clustering
Proceedings of the 9th International Conference on Geocomputation, Maynooth, Ireland

Abstract

Geodemographic analysis has been described as “the analysis of spatially referenced geodemographic and lifestyle data” (See and Openshaw, 2001, p.269) It is widely used in the public and private sectors for the planning and provision of products and services. Geodemographic analysis often uses clustering techniques which are used to classify the geodemographic data into groups, making the data more manageable for analysis purposes. Clustering identifies a number of geodemographic groups (clusters), each group having a
particular geodemographic profile. Each geographical area under consideration is then assigned to a group based on its similarity to the group profile. Fuzzy clustering offers a method of clustering that uses the principles of fuzzy logic to calculate a membership value for each subject in each of the groups. So rather than assigning a geographical area to a single group, each area is allocated a membership value in each of the
groups (clusters), thus helping to overcome the issues of ecological fallacy. The fuzzy clustering algorithm typically used in geodemographic analysis is Bezdek's fuzzy c-means clustering algorithm known as FCM (Bezdek et. al., 1984). Fuzzy geodemographic analysis using FCM has been investigated by Feng and Flowerdew (1998, 1999), and See (1999), but has received scant attention since - an exception being the recent investigation by one of the authors (Mason, 2006). This paper proposes a modification to the fuzzy clustering algorithm to incorporate geographical effects, suitable for geodemographic analysis.

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Integrating User-contributed Geospatial Data with assistive Geotechnology Using a localized Gazetteer

Rice, M.T.,  Hammill, W.C., Aburizaiza, A.O., Schwarz, S., and Jacobson,R.D. (2011) Integrating User-contributed Geospatial Data with assistive Geotechnology Using a localized Gazetteer, Advances in Cartography and GIScience. Volume 1, 279-291.

Abstract

We present a methodology for using cartographic-based processes to alert the vision-impaired as they navigate through areas with transitory hazards. The focus of this methodology is the use of gazetteer-based georeferencing to integrate existing local cartographic resources with user-contributed geospatial data. User-contributed geospatial data is of high interest because it leverages local geographic expertise and offers significant advantages in dealing with hazard information in real-time. For blind and vision-impaired people, information about transitory hazards encountered while navigating through a public environment can be contributed by end-users in the same public environment, and quickly integrated into existing cartographic resources. For this project, we build collections of user-contributed geospatial updates from email, voice communication, text messages, and social networks. Other necessary technologies for this project include text-to-voice software, global positioning devices, and the wireless Internet. The methodology described in this paper can deliver usable, cautionary reports of hazards, obstacles, or other time-variable concerns along a pedestrian network. Using the George Mason University campus as a study area, this paper describes how transitory events can be presented in usable form to a vision-impaired pedestrian within a usably short period of time after the event is reported. Buildings and other destinations of interest can be registered in a robust, eXtensible Markup Language (XML)-based, localized gazetteer. Walking networks, parking lots, roads, and landmarks are mapped as vector-based digital information. Any events or changes to the base map, whether planned and disseminated through official channels or reported by end-users, can be linked to a location in the network as established by the attributes cataloged in the localized gazetteer, and presented on an existing base map or in an assistive technology environment. For mobile applications, a vision-impaired pedestrian with a Geographic Information System (GIS) and a Global Positioning System (GPS)-enabled assistive device can receive an alert or warning about proximity to reported obstacles. This warning might include other information, such as alternative paths and relative directions to proceed, also referenced through the localized gazetteer. This research provides insight into challenges associated with integrating user-contributed geospatial in-formation into a comprehensive system for use by the blind or vision-impaired.

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Friday, 30 September 2016

Design Considerations for Haptic and Auditory Map Interfaces

Rice, M., Jacobson, R.D., Golledge, R.G., and Jones, D. (2005) Design Considerations for Haptic and Auditory Map Interfaces. Cartography and Geographic Information Science, 32 (4), 381-391http://dx.doi.org/10.1559/152304005775194656


Abstract

Communicating spatial information to the blind and visually impaired using maps and graphics presents many difficulties. Past research has offered advice to cartographers on topics such as tactile areal, point, and line symbolization; on perceptual problems related to dense linear features on tactile maps; and on the relationship between categorical data, measurement theory, and tactile discrimination. With this previous work as a foundation, we describe our research efforts with haptic and auditory maps - the Haptic Soundscapes Project. Haptic Soundscapes maps allow blind and visually-impaired individuals to feel map features through force feedback devices and hear auditory cues that add both redundant and complementary information. Recent experimental work by the authors has led to several recommended practices for cartographic data simplification, object size discrimination, shape identification, and general interface navigation. The authors also present haptic and auditory mapping examples to illustrate design ideas, algorithms, and technical requirements. Future prospects for automated haptic and auditory map creation are discussed and presented in the context of the past work in generating maps for the blind and visually impaired from cartographic data.

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Mapping the location, design and decline of London's psychiatric asylums (1831–2012)

Jacobson, R. D. (2015). Mapping the location, design and decline of London's psychiatric asylums (1831–2012)Journal of Maps12(4), 684-694. http://dx.doi.org/10.1080/17445647.2015.1061302


Abstract

This research analyses the location of psychiatric hospitals, previously known as ‘mental asylums’ built in the late nineteenth and early twentieth century in London, UK. Twenty of the largest facilities are geo-referenced using a mixed-methods approach including the use of archival documents, historical Ordnance Survey mapping, and a variety of recent digital datasets. The hospital locations are plotted on Ordnance Survey© [2013. Retrieved July 26, 2013, fromhttp://www.ordnancesurvey.co.uk/oswebsite/opendata/viewer/] Meridian™2 vector data. Inset maps provide comparative mapping of historic and current hospital sites using historic Ordnance Survey©, and recent Google™ Satellite data. Two of the largest former asylums of the ‘Epsom Cluster’ are explored in detail, Long Grove Hospital and West Park Hospital. Architectural design details and on-site photographs from 2007 and 2011 are used to demonstrate changes to luxury housing and of hospital decay. Of the 20 hospital sites mapped, 14 were converted into luxury housing, while only 2 remain as mental health facilities.