The GDS Data Bridge controls the initial conversion of the SICAD/open data into an ArcSDE secondary database, as well as the regular differential updates of ArcSDE data. GDS Data Bridge allows for the use of both the existing data in SICAD as well as in ArcGIS applications. Due to the numerous, flexible application- and user-specific customization possibilities, the GDS Data Bridge can be used in many different sectors, like e.g. utilities, land management or public administration. The original data management and administration in a SICAD Geodata Server is a prerequisite.
The GDS Data Bridge consists of various components. It allows for the implementation, control and monitoring of the processes that are required for the conversion. For the data transfer, GDS Data Bridge uses FME with the respective Readers and Writers as well as SICAD specific extensions within FME. Specific extensions within SICAD allow the performance of differential updates.
Prerequisite for the data conversion is the definition and description of both the source data model and the target data model. The rules for a data conversion will be defined in an FME mapping file. For standardized data models, like e.g. the conversion from a SICAD-UT data model into the ArcFM UT data model, there are mapping files that have been processed by AED-SICAD. However, the technical structure like “Which SICAD layers exist?” or “Which layers are to be represented in which ESRI feature classes and how?” differs from customer to customer. Therefore, the mapping files have to be customized according to the client’s existing source data structure. Here, customer-specific enhancements of the data model may be considered.
Having defined the conversion rules, the data can be transferred for the first time. Here, the geodata can be written into an ArcGIS geodatabase, either directly from a GDS with the GDS Reader for FME or from the SQD files with the SQD Reader for FME.
In order to perform a differential update, administration information is needed to describe coherences between SICAD elements and ArcGIS features. On the GDS side, these allow for recording changes of the data. When writing into the ArcGIS database, the administration information is needed to know which of the already existing data have to be processed.
With the GDS Data Bridge the entire process can be automated to a large extent. Meaning:
GDS Data Bridge can also manage and control various different conversion processes. For example: Only the gas network from a central database may be transferred into the ESRI geodatabase of department A, whereas the electricity network is transferred to the geodatabase of department B. Additionally, further content-specific restrictions for different target groups may be defined, so that, for example, only the type and the nominal value of the gas pipes will be transferred, but not the year of construction.
Furthermore, the GDS Data Bridge offers the possibility to add further processes. For instance, it might control the data transfer from a central ArcGIS geodatabase into decentral personal geodatabases.
The GDS Data Bridge is especially recommended when performing regular differential updates. However, it may also be used for a regular exchange of the entire database. Differential updates are only necessary when a daily update of the entire database is no more possible, due to large amounts of data.
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