Cartographica (2004) 39(2): 15-28.
Protection of Geoprivacy and Accuracy of Spatial
Information: How Effective Are Geographical Masks?
Abstract: Spatial analysis and mapping of georeferenced
individual-level data can help identify important geographical patterns or lead to
significant knowledge for dealing with specific social issues in a particular area.
However, given the need to protect personal privacy when using geospatial data, the
possibility for undertaking geographical analysis on certain types of individual-level
data is becoming increasingly circumscribed. This paper addresses the need to protect
geoprivacy while making individual-level georeferenced data available in such a way that
analytical results are not significantly affected. Using a data set of lung cancer
deaths in Franklin County, Ohio in 1999, the effectiveness of three geographical masks
with different perturbation radii (r) is examined. The findings reveal a rather consistent
tradeoff between data confidentiality and accuracy of analytical results. There seems to
be a threshold r value at which the results of analyses on masked data become substantially
different from the original results. An r that produces an area about the average size of
the census block groups of the study area achieves a desirable optimum trade-off between
privacy protection and accuracy of results. The study shows that implementing appropriate
geographical masks may help data managers or researchers establish the desirable level of
trade-off between privacy protection and accuracy of geographic information in a particular
Key Words: geoprivacy, GIS, privacy, geographical mask,
disaggregate data, lung cancer deaths, accuracy
View Full Paper .
Return to Kwan's Homepage