International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
geographic information, we lost the ability to connect it up and
thereby derive the knowledge and wisdom to address the major
issues that face us; not just at international level, but equally
importantly right down to the benefit of the individual citizen.
2. GEOGRAPHIC INFORMATION
2.1 Geography — the common denominator
It is a recognised fact that underpinning most information is
location. People live somewhere, people travel from one
location to another; crimes occur in buildings, in the street, in
all kinds of places, medical services are available at specific
locations and so on. Therefore geography has the potential to be
the common denominator to the (apparently) disparate
information we collect and handle each day.
2.2 Linking disparate information about a location
Information will be collected by an organisation for a specific
purpose e.g. education records, health records and so on. When
this information is combined with that of other organisations;
new information may emerge and establish new levels of
knowledge. For example information about health combined
with living conditions or the local industrial infrastructure may
reveal trends such as the prevalence of disease in certain
conditions and locations. Likewise information about education
attainment coupled with employment success or benefit claims
can highlight areas where groups or individuals are becoming
socially excluded. Once this knowledge is determined, some
form of investment may be appropriate to assist regeneration to
improve the social fabric of the community. Similar information '
collected over time would demonstrate whether the condition is
improving, or not, and therefore whether investment has been
successful.
Geography alone does not make the connection, since the close
proximity of two coordinates, of unknown pedigree, may only
imply a relationship. A more reliable link is formed when
objects are given identities c.g. buildings or addresses and
information is then linked to these objects via the identifier to
establish an explicit connection.
3. INFORMATION FROM MULTIPLE SOURCES
3.1 Data Collection
The way map or geographic information is collected and has
grown over the past decade has changed the entire complexion
of the geographic information [GI] industry. Until recently
photogrammetrists and surveyors went about processes which
would have been recognised 50 years, if not 100 years
previously — over the last 10-15 years that has changed and
continues to change.
3.2 The mapping or cadastral agency today
Today a database (of some kind) is central to an organisation
concerned with developing and maintaining geographic
information. Typically different people undertaking different
jobs will update this database. A surveyor in the field for
example, will now probably use a mobile computer with an
extract of the database to be updated contained on it. He is
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likely to use GPS to collect the coordinates and a coding system
to assign attributes and edit facilities and create objects e.g.
building features, street information or add attributes.
Measuring devices may use infra-red or other technologies
while instrumental observations will still be incorporated on
some occasions. The photogrammetrist is now likely to use
digital images from space or aerial images, in either stereo or
mono to create new data or update cxisting data. The
acquisition of data is becoming cheaper and simpler - but data
management more complex.
Other information is also increasingly available. For example
electronic builders plans can be used to update the data and
offer new services commonly referred to as “pre-build”
information. The utility company (gas, electric, water,
cable/telecoms) need such information to plan their distribution
network and link it into their existing records, before the
building takes place. The integration of pre-build information
into a database can also save costs and improve currency of
data, thereby providing a better service all round.
3.3 The wider GI community
Of course, the national mapping/cadastral agency [NMCA] is
not the only player. There are several organisations that collect
similar definitive levels of base data used for referencing, often
across government, and there are many others who collect data
for all kinds of applications (and normally reference it to the
NMCA data).
Figure 1. Example of reference information.
Topographic information and integrated postal addresses and
street centreline information.
Reference information
Framework information (also known as reference data) is
generally taken to cover that data or information which
underpins or is used as a reference base for applications data.
For example a user may record a scene of crime record
[application data] to a building or an address [reference
information]. While this is mainly the domain of the NMCA,
the state or region, local authorities or municipalities, the
hydrographic survey and sometime others contribute to
reference information, the exact m^4-! differs greatly from
country to country.
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