The Dictionary of Human Geography

(iv) data reporting, such as maps, reports
and plans.
The GIS acronym has tended to focus on
the software developed by specific corpor-
ations with less attention to the spatial data
that are the basis for knowledge generation.
Geographical information is information
aboutwheresomething is orwhatis at a certain
location. For example, we may have data from
a forest on where some of the few remaining
spotted owls live – which is geographical
information. What trees grow in the areas
inhabited by the owls is also geographical in-
formation, because it has a spatial component.
Spatial data are any data that have a location
that can begeocoded. Increasingly, data from
most domains include spatial data.
GIS are uniquely integrative. Where spatial
data are available, GIS can offer a range of
functionality. Whereas other technologies
might be used only to analyse aerial photo-
graphs and satellite images, to create statistical
models or to draft maps, these capabilities are
all offered together within a comprehensive
GIS. With its array of functions, GIS should
be viewed as aprocessrather than as merely
software or hardware. To see GIS as merely a
software or hardware system is to miss the
crucial role it can play in a comprehensive
decision-making process.
GIS has different uses and meanings among
a range of users. Municipalities, for instance,
view GIS as the software that allows planners
to identify residential, industrial and commer-
cial zones – and store tax information. It maps
the exact location and survey coordinates of
each taxable property, and provides answers to
queries such as: ‘How many properties would
be affected by the addition of an extra lane to
Highway 1 between 170th and 194th Streets?’
Populationhealthresearchers, on the other
hand, may use GIS to define the boundaries of
communitiesthat enjoy varying health out-
comes. In this instance, GIS is not a piece of
software, but a scientific approach to the prob-
lem: ‘How do we define crisp boundaries to
demarcate fuzzy and changeable phenomena?’
(cf.fuzzy sets). The latter is a fundamentally
philosophical issue that must be resolved
through computing and its answer lies some-
where between GIS and the underlying theory
ofgeographic information science. These
two types of users have different goals and
experiences of GIS. One is interested in
‘where’ spatial entities are or might be, while
the other is concerned with ‘how’ we encode
spatial entities (e.g. communities, urban/rural
areas, forests, roads, bridges and anything that

might appear on a map), and the repercus-

sions of different methods of analysis on

answers to geographical questions. The diver-

sity of GIS use is rooted in its history.

The development of GIS began in the

1960s, when the technology andepistemol-

ogythat underlie it were first being developed.

Methods of computerizing cartographic pro-

cedures were coincident with the realization

that mapping could segue neatly into analysis.

In 1962, Ian Harg, a landscape architect,

introduced the method of ‘overlay’ that was

later to become the definingmethodology

of GIS. He was searching for the optimal

route for a new highway that would be associ-

ated with suburban development. His goal was

to route the highway such that its path would

involve the least disruption of other ‘layers’ of

thelandscape, including forest cover, pastoral

valleys and existing semi-rural housing.

He took multiple pieces of tracing paper, one

representing each layer, and laid them over

each other on a light table. By visually exam-

ining their intersections, he was able to ‘see’

the only logical route. Ironically, none of

McHarg’s initial analysis was done using a

computer. The metaphor of overlay was,

however, integrated into early GIS, and be-

came the basis for a range of analytical tech-

niques broadly known as ‘spatial analysis’.

spatial analysis is differentiated from

‘mapping’ because it generates more informa-

tion or knowledge than can be gleaned from

maps or data alone. It is a synergistic means of

extracting information from spatial data. In

the early development stages of GIS, however,

few people recognized the power of analysis,

and the technology was generically referred to

as ‘computerized cartography’. As such, GIS

was unimpressive. Early computerized maps

were very primitive compared to the exquisite

maps produced through manual carto-

graphy. This comparison led to reluctance

among geographers to adopt GIS as a ‘substi-

tute’ for traditional cartography.

The questionable aesthetic merit of tradi-

tional maps was, however, a detraction from

the power of computerized spatial analysis.

That power was first explored in universities

in the late 1950s and early 1960s. Influenced

by the quantitative revolution and the

development of computers, researchers began

to develop tools that could be used to analyse

and displayspatialdata – though not always in

map form. One of the earliest computer cartog-

raphy systems was developed in Canada, the

brainchild of Roger Tomlinson and Lee Pratt.

Tomlinson had been using aerial photography

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GEOGRAPHIC INFORMATION SYSTEMS (GIS)