Geodetic Framework – software considerations

Software Considerations

During the exploration life of the project, data will pass through numerous software applications most of which will offer some functionality to convert and transform geo-spatial data between different coordinate reference systems.  Typically, a project is created and in doing so is referenced to a base project CRS.  Data is then added to that project where the data loader must identify the CRS to which the data is referenced at the time of input.  The data will be either stored in its original form or converted to the project CRS during data loading.  However, where data sets are referenced to several different CRS’ the data must be converted at some stage to bring it all into one common coordinate system.

Software applications that offer geodetic functionality have two fundamental components, namely:  an inventory of pre-defined geodetic parameters and a library of geodetic algorithms.  The latter using the parameters of the former.  Furthermore, many applications offer users the ability to create their own coordinate reference systems which are typically appended to the inventory of pre-defined systems.

Therefore, the inventory comprises a collection of pre-defined and user-defined geodetic parameters.  However, this is often limited to an individual installation as it is uncommon that E & P applications (developed by different vendors) share geodetic libraries from a central server.  Additionally, the geodetic parameter library may also be limited to a particular ‘instance’ of an application.

To ensure geo-spatial data is treated in a consistent fashion requires rigorous checks be made, for example:  the result of a coordinate operation (conversion or transformation) performed by application A must be the same that achieved by application B, within an accepted tolerance.   To aid the process it is important to ensure that the geodetic parameters used within the different applications are the same.  It is appreciated that different algorithms are available to perform similar operations but the parameters within by the algorithms must be like for like. Therefore, it is critical to know the authority from which the geodetic parameters are sourced.

 

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