Spec is missing 'declination' - body's current pointing angle above horizon

Hello,

I was reading the draft W3C spec for GeoLocation here http://dev.w3.org/geo/api/spec-source.html

It occurred to me that there seems to be a missing attribute in the Position Interface.
You have the following (inherited from the World Geodetic System [WGS84] )....

latitude
longitude
altitude
accuracy
altitudeAccuracy
heading
velocity
timestamp

What is missing from this list is the notion of the current pointing angle above the horizontal (or tangent to the earth's surface at the relevant Lat and Long). May I suggest that "declination" would be the appropriate attribute name.

http://en.wikipedia.org/wiki/Declination

This would be extremely useful, and would enable specifying a body's current motion in space, as well as its position on (or above or below) Earth's surface. The compass heading alone does not allow a proper 3D vector to be constructed (rather, only motion along the surface).

Another example: if a user knows their position in a city and wishes to point at something in their environment in order to retrieve information about it, knowing the angle above the horizontal as well as the direction is extremely important. It would be the difference between pointing at a drain at ground-level, or a shop at the horizontal level, a second-storey apartment, or the moon.

I was thinking along the lines of using a service like this one http://www.earthmine.com/media/ (I am not affiliated to this company).

Please excuse me if this aspect has already been considered, but it seemed important enough to mention to you. I would be interested to hear your thoughts on this.

Best Regards,

Mathew Tizard