Descriptive review of geographic mapping of severe acute respiratory syndrome (SARS) on the Internet

Abstract

From geographic mapping at different scales to location-based alerting services, geoinformatics plays an important role in the study and control of global outbreaks like severe acute respiratory syndrome (SARS). This paper reviews several geographic mapping efforts of SARS on the Internet that employ a variety of techniques like choropleth rendering, graduated circles, graduated pie charts, buffering, overlay analysis and animation. The aim of these mapping services is to educate the public (especially travellers to potentially at-risk areas) and assist public health authorities in analysing the spatial and temporal trends and patterns of SARS and in assessing/revising current control measures.

Figure 1

Corda's world map of SARS. Web browser screenshot by this author of Corda's world map of SARS displaying data for each country affected by SARS as of 11 July 2003 . As the mouse moved over a country, a ToolTip appears with the cumulative number of reported cases. An accompanying graph shows SARS deaths by country. Users can also drill-down into the United States map to view how many cases have been reported in each state.

Figure 2

Corda's SARS worldwide infections/recoveries/deaths time line graph. Web browser screenshot by this author of Corda's SARS worldwide infections/recoveries/deaths time line graph as of 4 July 2003 .

Figure 3

One of MapAsia's SARS distribution maps for Hong Kong. Web browser screenshot by this author of one of MapAsia's SARS distribution maps for Hong Kong as of 24 April 2003. Legend: orange circle buffer: some other case(s) within 250 m; yellow circle buffer: no other case within 250 m; red triangle: infected case; purple triangle: de-listed case. The toolbar to the left of the map provided the sort of functionality found in a standard desktop GIS interface.

Figure 4

One of MapAsia's provincial SARS distribution maps of China. Web browser screenshot of one of MapAsia's provincial SARS distribution maps of China as of 23 April 2003. Note the choropleth rendition and graduated pie charts, e.g., the small pie chart over Shanxi (162 cases) and the large one over Guangdong (1359 cases), each with colour-coded slices representing the relative numbers of discharged/under treatment/dead cases in the corresponding province.

Figure 5

ESRI China's "SARS GIS" – SARS case distribution in Hong Kong. Web browser screenshot by this author of ESRI China's "SARS GIS" – SARS case distribution in Hong Kong as of 30 April 2003 . Note the list of affected building addresses (bottom left).

Figure 6

One of Hong Kong SARS distribution maps by Hong Kong Yellow Pages. Web browser screenshot by this author of one of Hong Kong SARS distribution maps by Hong Kong Yellow Pages as of 25 May 2003 . The map appearing in this screenshot highlights the relationship between the predominant housing type and infected buildings. The only infected building seen in this screenshot (Wing Shui House – red dot/black arrow) falls within a public housing area (yellow).

Figure 7

Hong Kong Yellow Pages map showing the progressional change of SARS-infected buildings in Hong Kong. Web browser screenshot by this author of a map by Hong Kong Yellow Pages showing the progressional change of SARS-infected buildings in Hong Kong as of 25 May 2003 . One can clearly see at a glance that SARS situation in Hong Kong was already under control by that date. The green dots on this map represent "cleared buildings" and there are no red dots representing "buildings infected within one day".