In kOS, this code would store a list of altitudes around the equator:
local the_body is Mun. // or set to some other body to measure.
local alt_list is list().
local startlong is 0.
local stoplong is 360.
local steplong is 0.5. // samples 0.5 longitude degreees apart. Set smaller for more fine-grain measure.
for long in range(startlong, stoplong, steplong)
{
// latitude = 0 to hardcode equator, longitude varies through the loop:
alt_list:add( the_body:geopositionlatlng(0, long):terrainheight ).
}
// Now alt_list is a list of terrain heights around the equator.
// Do whatever statistical work on that list that you like in the lines below...
// for example - to get the mean:
local sum is 0.
for long in alt_list
set sum to sum + long.
local mean is sum / alt_list:length.
Warning: the above code is not tested. I typed it in without trying to run it. It may have errors.
(1) - The function call : VANG(ship:up:vector, ship:srfprograde:vector) will give you the angle between straight up and your surface-prograde vector. (I assume you want surface and not orbital here). So, for example, a pitch of 80 would mean there is 10 degrees angle between up and prograde. If you do 90 - VANG(ship:up:vector, ship:srfprograde:vector) then you should get the pitch number you are looking for.
(2) - There is no such thing in kOS. Instead you can explicitly mention which you are interested in because prograde comes in two varieties - surface and orbital. You can say srfprograde for surface, or just prograde for orbital. You can say ship:velocity:surface or ship:velocity:orbit to get velocity vectors in the two frames. For target-relative there isn't a shortcut, but you can always subtract your target's velocity vector from your velocity vector to get the same thing the navball would have shown you in target mode.
(3) - Not really. But if you want this kind of information, look at lib/navball in the community library. It's possible to get this information with a few lines of kOS script code and this example shows how.
The documentation describing the functions is here: https://github.com/KSP-KOS/KSLib/blob/master/doc/lib_navball.md
The actual functions themselves are here: https://github.com/KSP-KOS/KSLib/blob/master/library/lib_navball.ks
