[pcap-ng-format] Proposing new block type for PCAP-NG (UNCLASSIFIED)

[Guy Harris]

On Apr 1, 2015, at 6:05 PM, Guy Harris <guy at alum.mit.edu> wrote:

> Is "mean sea level" here something defined by a particular specified standard, in which case the proposal should indicate what standard that is, or is the particular standard being used something that can be chosen, in which case the Location Provider Block should probably indicate what standard is being used.

OK, there's the WGS84 ellipsoid (a simple geometric figure), to which the 3GPP altitudes are relative, and the WGS84 geoid (not so simple, as it takes varying Earth density and gravitational field into account).  By "mean sea level" are you referring to the WGS84 geoid, or something else?

	https://en.wikipedia.org/wiki/Geoid

says

	If the ocean surface were isopycnic (of constant density) and undisturbed by tides, currents, or weather, it would closely approximate the geoid. The permanent deviation between the geoid and mean sea level is called ocean surface topography.