Marc Linsner wrote:
> For those who are struggling with this, it is not our intention to
> (re)define zero altitude. We are simply attempting to provide a
> mechanism for people who understand altitude values to share them
> amongst each other via a standardized mechanism. If one were to receive
> such data, it is assumed that they will understand the definition of
> zero altitude within the jurisdiction/authority from which the data
> originated. Some map datum define zero altitude, some don't. For those
> that don't, we define mean low tide.
Like the datum, what's wrong with providing an indication of the unit of
the measurement?
I think it is generally a bad idea to assume that all parties along a
chain of transmission know what the data meant initially. This only adds
a modest number of bits to the format, given that the number of choices
appears to be on the order of two.
Received on Wed Jul 2 21:41:21 2003
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