Recently it has become more common in city and canton governments to manage and update
spatial data of all parts of the government in one central data pool called geodata
warehouse (a spatial database management system). This makes huge savings as the data
is now stored redundance free and needs to be updated only once. Until now, some data
needed to be stored and updated in different departements of the government. This
made it enormously difficult to have current data in all places. Additionally, when
doing bigger projects the data can now simply be taken out of the geodata pool and
does not need to be gathered in tedious and lengthy work.
The most important characteristics of such database systems:
Concurrent
Use
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A central geodata warehouse is a nice example of concurrent use of a database system.
On the one hand different users get their data from it - the employees of the different
departements. On the other hand different application software (e.g. GIS system) are
used to access the geodata warehouse. Therefore, it is possible that the forestry
departement uses GIS software A for access to the data while the surveyor departement
uses GIS software B.
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Separation of
Data and Applications
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As described above, different users’ with different applications get access to the
data. This is only possible, if the data is separated from the applications. If data
were connected to the application it would be much work to process the data in way
that other applications could read and use it. This independence is especially important
in cases where the DBMS software needs replacement. With the separation of data and
applications this is possible without having to re-write all of the application software.
Example: A Microsoft Word file (where the data is included in the application format)
is quite difficult to open with the Microsoft Excel software even though both applications
are made by the same company.
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Data
Persistence
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The capture of geodata: and other data is most often a lot of work and very expensive. Therefore, data persistence
is a very important characteristic of a geodata warehouse. This way, it is possible
to ensure that data is not lost and needs then to be replaced, which is costly. |
Data Integrity
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Governmental data often give information about legal conditions for example, the cadaster.
Therefore, these data need to be thoroughly correct and reliable. That is achieved
through the definition and following of specific consistency requirements and rules.
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