UseCase 3, Use Case 4, UseCase xx : referenceElevation

[sgrellet]

Many discussions around this in many use cases and standardisation group (esp in GWML2)

One expression of need not to forget

• shapes/logs still remain are relative : first vertex is 0,0,0 and other vertices are dx,dy,dz – dz
• with referenceElevation
• but instead of attaching the referenceElevation to the well, attach it to the logs instead because
  • this could evolve throughout the life of the well/borehole
  • and because various work domains don't always reuse the same referenceElevation
• within referenceElevation have
  • a/ the Z of the ground (with SRS) and precising what type of ground it is ('Natural', 'after being reworked before putting a concrete pad', ...)
  • b/ the height of the 'benchmark' ('repère' in French) above the Z of the ground
    There is a need to differentiate both because over decades one or the other (or both) can change -> easier when stored separately
  • who/when this was measured

[John-Sharples]

That looks like a good summary - don't need to reinvent the wheel.

[sgrellet]

add depth clarification

• measured depth
• true depth

[sgrellet]

Shall also be linked with #56 discussions