[Shop-talk] plumping question and sandrock sewers

[Randall]

> USGS sea level reading - 694.10  =  Saint Paul City Datum

Phil, are you sure that's Mean Sea Level ?  Sounds to me more like an
ellipsoidal height (meaning the theoretical model of the entire earth's
surface that datums like WGS-84 are based on).  There are of course, some
places that are below MSL, but even Death Valley is only 282 feet below.

> Sometimes a surveyor will not call for benchmarks and just pick a random
> place on the site and call it "100.00".

Which of course is the same basic process that produced your "Saint Paul
City" datum.
<G>

Randall