sphericalToLatLon[{theta_, phi_}] := {Rescale[
theta, {0, Pi}, {-90, 90}], Rescale[phi, {-Pi, Pi}, {-180, 180}]}
latLonToSpherical[{lat_, lon_}] := {Rescale[lat, {-90, 90}, {0, Pi}],
Rescale[lon, {-180, 180}, {-Pi, Pi}]}
geoSteps[{pos1_, pos2_}] :=
With[{dir = GeoDirection[pos1, pos2]},
Table[First@GeoDestination[pos1, {d, dir}], {d,
QuantityMagnitude@UnitConvert[GeoDistance[pos1, pos2], "Meters"] //
Append[Table[i, {i, 0, #, 1000000}], #] &}]]
Manipulate[{p1, p2, p3, p4} // Map@sphericalToLatLon //