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Locating socio-economic activities with GIS in Chines cities
Place name. From a geographical point of view, a conventional place represents an area that may
relate to a legend or an event in history. If all the places in a city are geo-referenced, they could be
used for less-precise location reference. One of the characteristics of places is that their areas may vary
dramatically and they don’t have clear boundaries. This phenomenon poses troublesome problem of
data representation. A practical solution to this dilemma is to find a point that can best represent the
place and to regard the place as a point entity in computer database. All points of places in a city
together may cover the urban area by using irregular tessellation representation in a GIS (Worboys,
1995). An interesting fact is that bus stops are mostly named after the conventional names of the place.
Considering the importance of public transport in Chinese urban systems, the names of transit stops
are well known by travelers. More importantly, the stops cover a large proportion of the build-up area.
Therefore, these stops could possibly serve as location references in the lack of precise location
measures. Although the spatial accuracy of place reference is not very high, the collection of these
data is not demanding. This means the reference base can be set up with relatively less input but can
still satisfy the needs of some applications.
Site of employer (work unit). A site of employer (or a work unit in China) is a place with landmark
where employment taking place, such as a public agency, a business park, a university, or a shopping
center. Because of their popularity, these sites are frequently referred to as references by travelers in
everyday life. These sites themselves could be precise in geographical location and cover a moderate
area. In urban travel demand modeling, employer’s sites are important attracting points and are
especially emphasized in disaggregate transport survey. In a metropolitan city like Wuhan, many large
work units can serve as referencing places because of their popularity or prominence.
Building. The most accurate way of identifying locations is to designate the building (landmark) in
which activities happen. These buildings are available from topographical maps or cadastral maps that
are available from departments of land administration in Chinese municipalities. If the buildings are to
be utilized as a referencing base for activities, their names have to be clearly identified in the database.
Using buildings as referencing base is still a task that facing many difficulties. The biggest problem
lies in the possibility of generating and maintaining such a huge data set. The closest successful
example is the Address-Point dataset maintained by the Ordnance Survey of UK, which contains more
than 25 million addresses.
Administrative unit. The administrative hierarchy of an urban municipality in China is like this: the
city - Districts - Streets - Resident Committee. The system has been used for resident registration and
socioeconomic statistics. Due to its strong structure, the hierarchy is frequently applied in location
expression of activities. However, the resident committee rarely appears in location expression, and
the geographical boundary has not been very clear. In address expressions the administrative units are
usually used to supplement street addresses.
Implementing location referencing in Wuhan, China
Wuhan is a metropolitan city with a population of about 7 million in central China. It bears typical
characteristics that can be found in other large cities of China.
The components of address expressions
The standard postal address should contain street address and postcode. In Wuhan, as the postcode
areas are large and don't correspond with any other spatial units, they cannot fulfill the needs of
location reference alone. Street address has been recommended by postal offices and has been used
more and more frequently. In the absence of street addresses, names of companies or institutions are
usually used as substitutes in postal service. In practice, various methods may be used together when
stating an address. This poses the problem of identifying different parts in an address expression. An
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