This specification contains a detailed topographic survey specification and supporting quality assurance (QA) procedures for 1:250 urban works as implemented by the QBN Project Office and Dublin City Council. It has been developed over a period of years by a working group including members representing the interests of the City Council, private land survey firms, local government, civil engineering consultants, professional survey organisations, and survey software developers. In addition to the specification itself, the document provides a checklist of QA activities to be carried out to ensure that any given survey fully meets the specification in terms of accuracy and content.
The specification has been applied and refined over a number of large projects such that it has been shown to fully meet the demanding requirements of dense urban topographic surveys while being readily achievable by the survey contractor in a cost effective manner. Specifically, the specification has been shown to deliver consistent results in terms of high quality cartographic and 3d model output to AutoCAD / MX / Microstation and SCC, with well-defined relative and absolute accuracies.
The specification is based in the ITM grid, while still fully supporting the older IG75 grid. As such, the specification has proven a good mechanism for transitioning between the two grid systems. The specification currently requires that all outputs be provided in both grid systems, with the intention that the requirement to provide outputs in the older grid can be dropped once it becomes redundant.
This is the first full public release of the specification, and as such there is a bias towards the specific needs of the QBN Project Office in terms of content, accuracy, and desired output formats. It is intended that the specification will be updated based on feedback to this document to meet broader requirements.