Objectives: To investigate the relationship between the use of Category Three or Four narcotics (illicit drugs) and geographical characteristics of the locations of seizures using the Geography Information System (GIS). Methods: Using the seizure data from a city over five years (2011-2015), we conducted a series of spatial analyses using ArcGIS software. We started with global analysis, and determined the seizure rate in different districts using visualized figures. Local analysis was then performed using two kinds of hot-spot analyses: Getis-Ord Gi∗ and kernel density analysis. Finally, the change rates in the number of seizures over the years for individual district were determined. Results: Estimates of the average number of nearest neighbors showed that the ratio Rs were all less than 1 for the five year period, indicating a strong spatial aggregation of the seizure of illicit drugs. The district-specific seizure rate showed that "high-rate areas" started with a few and then spread to others. Local analyses confirmed that some southwest districts could be designated as hot spots since their Getis-Ord Gi∗ reached statistical significance. Combining the seizure locations with street maps in Geospatial PDF helped identify street characteristics associated with the use of illicit drugs. The results of kernel density analysis also indicated that the spots with the highest densities were located within the southwest districts and their neighbors. In addition, the rates of change in the number of seizures by year differed in individual districts. Conclusions: GIS-based visual displays with hot-spot analysis provided clues to the identification of geographic characteristics associated with the seizure of illicit drugs. These may enhance location-tailored strategies to prevent the use of illicit drugs.
Date:
2016-12-15
Relation:
Taiwan Journal of Public Health. 2016 Dec 15;35(6):671-684.
