The national herd prevalence and spatial distribution of Neospora caninum infected dairy herds in Sweden were investigated. The study was based on a bulk milk survey comprising samples from 2,978 herds. Test-positive herds were found in all parts of Sweden and the overall prevalence of test-positive herds was 8.3% (95% confidence interval = 7.3-9.3%). The presence of spatial autocorrelation was...

This comparative analysis examines the suitability of commonly applied local cluster detection algorithms. The spatial distribution of an observed spatial crime pattern for Houston, TX, for August 2005 is examined by three different cluster detection methods, including the Geographical Analysis Machine, the Besag and Newell statistic, and Kulldorff’s spatial scan statistic. The results suggest ...

The most significant aspect of a geochemical exploration program is to define and separate the anomalous values from the background. In the past decades, geochemical anomalies have been identified by means of various methods. Most of the conventional statistical methods aiming at defining the geochemical concentration thresholds for separating anomalies from the background have limited the effi...

The spatial scan statistic was applied to density-smoothed data that approximated the spatial distribution within the area and reduced the potential bias produced when location data have been aggregated for large areas. The method is illustrated, using data on the location of foot-and-mouth disease (FMD) outbreaks in Iran. Data examined were 4477 FMD outbreaks reported on a per province basis b...

BACKGROUND West Nile virus (WNV) is a vector-borne illness that can severely affect human health. After introduction on the East Coast in 1999, the virus quickly spread and became established across the continental United States. However, there have been significant variations in levels of human WNV incidence spatially and temporally. In order to quantify these variations, we used Kulldorff's s...

This paper proposes a spatial clustering model based on self-organizing feature map and a composite distance measure, and studies the knowledge discovery from spatial database of spatial objects with non-spatial attributes. This paper gives the structure, algorithm of the spatial clustering model based on SOFM. We put forward a composite clustering statistic, which is calculated by both geograp...

BACKGROUND Aggregation of spatial data is intended to protect privacy, but some effects of aggregation on spatial methods have not yet been quantified. METHODS We generated 3,000 spatial data sets and evaluated power of detection at 12 different levels of aggregation using the spatial scan statistic implemented in SaTScan v6.0. RESULTS Power to detect clusters decreased from nearly 100% whe...

Map comparison methods are used to express the similarity between maps. They are amongst others used in validation and calibration procedures of spatial models. It is found that traditional map comparison methods do not distinguish small differences from large differences, which leads to comparison results that are not in accordance with human judgment. In this paper a relatively new method for...

OBJECTIVE This paper describes a new class of space-time scan statistics designed for rapid detection of emerging disease clusters. We evaluate these methods on the task of prospective disease surveillance, and show that our methods consistently outperform the standard space-time scan statistic approach. BACKGROUND The space-time scan statistic [1] is a powerful statistical tool for prospective...