Project Management and Mapping AS

 

 

CRONO GIP details - Quality Control routines

Development of Quality Control Routines in CGI

One of the main objectives in CRONO GIP was to enhance CGI’s capability to carry out quality control of geodetic products according to internationally accepted standards. This task can be divided into two main components:

  • Development of formal quality assurance documents describing the policies, methods, and quality elements.

  • Development of tools and work-procedures for executing QC for each geodetic product.

Regarding the first task, this work resulted in a comprehensive set of specifications and quality control documents.

The development of tools and procedures for executing QC was done with the following in mind:

  • Some quality controls can be automated using software, for example those concerning the logical consistency and formatting of digital data files.

  • Some quality controls can only be done manually and are very time consuming. These are done either by field inspections or in some cases by in-house inspection of delivered data, both analogue and digital.

  • During quality control the operator needs an efficient tool which enables him/her to do the following:

    • Keep track of each defined quality element for the particular product as well as control-type, tolerance, sampling information, etc.

    • Log each result as the control work is being carried out.

    • Automatically indicate whether a control is accepted based on the given tolerances and rules for sample techniques.

    • Automatically print the QC report after the control work is finished.

Quality Control Logging and Reporting Spreadsheets

To enable the QC operator to efficiently log and report quality control work, a number of Excel based tables were developed, one for each geodetic products. The spreadsheets enable the QC operator in CGI to do all that is mentioned above. The picture below shows an example of such a spreadsheet. Note that all fields in green colour are automatically calculated by the tool itself, which is good practice in quality assurance to minimize human errors.

 

FME Workbench files for Automated Controls

Topographic Data and DTM data are well suited for automated controls using software. The topographic data specifications comprise a very comprehensive mapping catalogue of layers, colours, and styles in a Microstation design file. It would be next to impossible to control this kind of data satisfactory without using software automation.

The Feature Manipulation Engine (FME) software was chosen as the tool to implement such quality controls. The advantage of this software is that it is relatively cheap and it supports more or less every known GIS format in the market. 

The FME software can be configured using so-called workbench files, which instructs the FME software how it should interpret the input data. During the CRONO GIP project FME workbench files were developed to do the following:

  • Check that topographic data is according to mapping catalogue in product specifications, which involves many hundred different combinations of layers, colours and styles.

  • Check that topographic data is geometrically and topologically correct according to specification.

  • Log any error to specifically named output files used for reporting.

  • Convert topographic input data on DGN format to an intermediate object oriented format (features/attributes), which can be easily uploaded by SGA to their topographic database.

  • Similarly to topographic data, a workbench file was also developed to control DTM data.

The figure below shows and example of the comprehensive workbench file for controlling topographic building data:

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