Communication tools, transactional cards, personal locator and
navigational systems, radio frequency identification devices, and
surveillance cameras all have the capability to provide information
about one’s location and behavior. In particular, geospatial
technologies, such as global positioning systems (GPS) and geographic
information systems (GIS), are powerful in their scope and capability
to converge locational and tracking technologies. Geographic
information systems (GIS) aggregate data and information from multiple
sources including satellite, aerial, and infrared imagery, geodetic
information, and “layered” attribute information (such as property
records). These aggregates of data, like data mining systems, create
collected bits of information that generate valuable and powerful
profiles of objects.
Boundaries of intrusiveness
There are a growing number of high resolution satellites providing
imagery for GIS systems. These eyes in the sky raise the question of
“how close is too close”, or at what level (i.e. resolution) do these
images become intrusive to individual privacy. High resolution
commercial satellite systems currently allow general features of
facilities to be readily observed: the QuickBird system
provides 0.6mGSD resolution satellite images with 1-14 day sampling. At
this resolution, features such as buildings, roads, and large objects
are visible (for example, see a 0.6m GSD  image of the Washington D.C. airport).
GIS systems also include aerial images that provide details at
<0.3mGSD. Thus, precise geolocation information can be discerned in
geospatial systems, especially when information is aggregated with
It is tempting to say that only very high spatial resolution is
intrusive. But consider the situation of a low spatial resolution
object (such as a dot representing an individual) overlayed onto a map
and then captured in near-real time, i.e., at high temporal resolution.
For example, one can identify a teenager’s location on a map, and then
track his movements in near-real time through GPS data. In this
scenario, even without high spatial resolution, one’s behaviors and
actions are identifiable, allowing a system to track movements and
infer from that information one’s actions and behaviors. Thus, the combinatory effect of
high temporal resolution, with either low or high spatial resolution,
identifies and becomes intrusive in ways that singular information
would not. This means both the spatial and temporal contexts must be
evaluated when determining intrusiveness.
The new Real-time Rome project announced
last month by MIT provides an example of the applications of GIS
systems and visualization tools, using data from cell-phone usage,
pedestrian and transportation patterns, to map usages of urban space.
While visualization is based upon aggregated information,
individual-level data is collected.
Rights to locational privacy
What rights do we have to locational privacy? In the United States,
common law gives rise to four generally recognized privacy torts: (a)
intrusion upon a person's seclusion; (b) public disclosure of private
facts; (c) publicity in a false light; and (d) misappropriation of
one's likeness. However, the public disclosure tort is limited by the
clause “if an event takes place in a public place, the tort is
unavailable” (Restatement (Second) of Torts 652D, 1977), and the courts
have generally ruled that a person traveling in public places
voluntarily conveys location information. But courts have also
recognized that “a person does not automatically make public everything
he does merely by being in a public place” (Nader v. GMC, 1969, 570-71; see also, Doe v. Mills, 1995).
Constitutional protections for privacy, derived from the Fourth
Amendment, restrict government intrusion into our personal life through
searches of persons, personal space, and information. In the seminal
case Katz v. United States (1967), the United States Supreme Court held that government eavesdropping of a man in a public phone booth violated a reasonable expectation of privacy because
the Fourth Amendment protects “people, not places.” The Court held that
whatever a person “seeks to preserve as private, even in an area accessible to the public,
may be constitutionally protected” (389 U.S. 347, 352, emphasis added).
This gave rise to the two-pronged test of constitutional protection:
whether an individual has an expectation of privacy that society will recognize as reasonable.
Case law has interpreted these locational privacy rights more
specifically, examining intrusions of technology into the private
sphere, government searches that are technologically enhanced, and the
use of mobile devices and telecommunication information to derive
locational information. While Fourth Amendment protection doesn’t
extend to that which is knowingly disclosed to the public, the courts
have ruled that the use of technologies not available to the general
public can violate the privacy one reasonably expects (Kyllo v. U.S.,
2001). But courts have shown a willingness to allow law enforcement to
use technologically-enhanced vision for searches, including flying over
a fenced backyard (California v. Ciraolo, 1986), a greenhouse (Florida v. Riley, 1986), or an industrial plant (Dow Chemical v. U.S., 1986), suggesting that the “open fields” doctrine  brings no reasonable expectation of privacy. 
This protection does not extend to deriving location information
from communication devices. Transaction information such as telephone
numbers is not protected (Smith v. Maryland, 1979), but providers are prevented from releasing information that discloses the physical location of an individual (CALEA, 1994/2000; U.S. Telecom v. FCC,
2000). However, using mobile communication devices as tracking devices
to derive location information is not constitutionally protected (U.S. v. Meriwether, 1990; U.S. v. Knotts, 1983; U.S. v. Forest,
2004), as courts have ruled that individuals using cell phones,
beepers, and pagers do not have a reasonable expectation of privacy
when moving from place to place. (This interpretation continues to be
Furthermore, while the Electronic Communication Privacy Act (1986)
protects against unauthorized interception and disclosure of electronic
communications (18 USC § 2510-22; 2701-11), it excludes tracking
devices (§ 3117). However, the Wireless Communication and Public Safety
Act (1999), explicitly protects location information in wireless
devices, (47 USC § 222, §§ f), requiring customer approval
for disclosure.  But the Patriot Act (2001) has nullified some of
these protections, granting broad authorities for government
surveillance, including the ability to use roving wiretaps.
In summary, legal protection for location privacy in the United
States is inconsistent and sectoral, providing coverage under certain
situations and for specific technologies.
Emerging geospatial technologies, through their power and
invisibility, re-architect our public space and change our patterns of
disclosure and interaction with others in this space. Architecture
regulates the boundaries of accessibility in human interaction. Just as
doors and windows increased barriers and expectations of privacy in 17th century rural villages, modern technologies are decreasing
these barriers, by providing new capabilities to extend or enhance
human senses (our eyes, ears, and memory). This changes the
architecture of our public sphere, and shifts our constructions of
public-private space and boundaries. These shifts are at odds with our expectations
and sense of personal space, thus leading to a sense of intrusion. In
turn, this changes our awareness of disclosing and interacting with
others in this space.
At the same time, the pervasiveness and invisibility of locational
technologies mean that control of access to information about oneself
is not available. We are unaware of the presence and activity of such
technologies, and thus lack autonomy in regulating the boundaries of
accessibility. This has implications for understanding our navigation
and negotiation of connectivity in the modern world. In addition, the
aggregation of information – whether in data mining systems or
geographic information systems – creates very powerful identifiers.
Whereas a single bit of information may not be threatening, aggregated
bits constitute a pattern of behavior or a profile that can reveal much
information and threaten one’s privacy and liberty.
Thus, the unique threats of geospatial systems as technologies of identification are based on two primary factors: a) aggregated data creates very powerful identifiers; and b) the invisibility of data collection and use results in a loss of agency in the process by which we are identified. These in turn influence how we interact in our society, and by extension, the construction of our identities.
This raises questions that require further study: What do these
technologies of identification mean for our construction of identity in
digital realms? That is, when technologies extend human senses, what
happens to our construction of personal space and retreat, and our
concept of reasonable expectations of privacy? Further, under the current legal framework, how do we address new constructions of space
(e.g., reconnaissance of space above private property), new
technologies of intrusion (e.g., infrared, RFID, GPS, GIS), and new
constructions of scope (e.g., aggregated information)?
Additional research is needed to understand how individuals define
these ambiguous boundaries, our expectations of private space, and the
mechanisms by which we negotiate shifting boundaries in the face of
emerging locational technologies.
 Westin, A. F. (1967). Privacy and Freedom. New York: Atheneum
 GSD, ground sample distance, refers to the pixel representation of
the distance on the ground between two components, in digital imagery.
 See Hester v. United States, 265 U.S. 57 (1924) and Oliver v.
United States, 466 U.S. 170 (1984) for a discussion of the “open fields
doctrine” which suggests that constitutional protection is not extended
to the open fields.
 Curry, M. (1996). In plain and open view: GIS and the problem of privacy. Paper presented at the Conference on Law and Information Policy for Spatial Databases, Santa Barbara, CA.
 Edmundson, K. E. (2005). Global positioning system implants: Must
consumer privacy be lost in order for people to be found? Indiana Law Review, 38.
Lorraine Kisselburgh is a doctoral student in Media,
Technology, and Society (Department of Communication) at Purdue
University. Portions of this article were presented at the NYU
Symposium on “Identity and Identification in a Networked World” and at
the International Communication Association in Dresden Germany, and
have been submitted for publication in the “ICA 2006 Theme Session
Proceedings.” The author wishes to acknowledge the support of Eugene
Spafford (Department of Computer Science, Purdue University) in the
conceptualization of this project.