Spatio-temporal evaluation of cattle trade in Sweden: description of a grid network visualization technique

Widgren, Stefan and Frössling, Jenny (2010) Spatio-temporal evaluation of cattle trade in Sweden: description of a grid network visualization technique. Geospatial health , 5 (1). pp. 119-130. ISSN 1970-7096

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Understanding the intensity and spatial patterns of animal transfers is of prime importance as geographical moves play an important part in the spread and potential control of contagious animal diseases of veterinary importance. For the purpose of visualizing all registered between-herd animal movements in Sweden between 1 July 2005 and 31 December 2008 by map animation, a grid network technique based on the Bresenham line algorithm was developed. Potential spatio-temporal clustering of animals registered as sold or purchased based on location and month of trade was also detected and tested using a spatial scan statistic. Calculations were based on data from 31,375 holdings and 3,487,426 head of cattle. In total, 988,167 between-herd movements of individual bovines were displayed in a sequence of maps covering three and a half years by 2-week intervals. The maps showed that several cattle movements, both short- and long-distance, take place in Sweden each week of the year. However, most animals (75%) were only registered at one single holding during the study period and 23% were sold to a different holding once. Spatial scan statistics based on data from the year 2008 indicated uneven distributions of purchased or sold animals in space and time. During each autumn, there was an increase in cattle movements and October and November showed significantly more cases of sold or purchased animals (relative risk ~1.7, p = 0.001). Based on the results, we conclude that cattle trade is constantly active at a considerable level. This, in combination with possibly insufficient biosecurity routines applied on many farms, constitutes a risk that contagious diseases are spread in the population. The grid network maps were generated through the use of open-source tools and software in order to decrease software costs and facilitate sharing of programme code. In addition, the technique was based on scripts that allow for the inclusion of iterative processes and that comprise all main parts of map creation. Thereby, a large number of maps can be generated and the demands for high reproducibility are met.

Item Type: Article
Uncontrolled Keywords: Bresenham line algorithm, open-source, map animation, cluster analysis, Sweden
Subjects: 300 Scienze sociali > 380 Commercio, comunicazioni, trasporti > 380.1 Commercio
600 Tecnologia - Scienze applicate > 610 Medicina e salute (Classificare qui la tecnologia dei servizi medici) > 614 Medicina legale; incidenza delle malattie; Medicina preventiva pubblica > 614.4 Incidenza delle malattie e misure pubblica per prevenirle (classificare qui l'Epidemiologia, l'Epidemiologia clinica) > 614.42 Incidenza delle malattie, e misure pubbliche per prevenirle. Incidenza (classificare qui la prevalenza; la Geografia medica; l'Epidemiologia spaziale; i rilevamenti sanitari)
600 Tecnologia - Scienze applicate > 630 Agricoltura e tecnologie connesse > 636 Allevamento di animali > 636.2 Ruminanti, Camelidi, Bovidae, Bovini
900 Storia, Geografia e discipline ausiliarie > 910 Geografia e viaggi > 910.285 Geographic information systems
Depositing User: biblioteca 7
Date Deposited: 04 Apr 2011 11:59
Last Modified: 04 Apr 2011 11:59

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