Create Lifting Gas
Conjuration (Creation)
Level:  Clr 2, Sor/Wiz 2
Components: V, S
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Effect: up to 1000-cu. ft. /level
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No
This spell creates up to 1000-cu. ft. of lifting gas per caster level at any point within range of the spell.  If the lifting gas is not created inside of a mostly airtight container, the spell fails. If the caster attempts to create the lifting gas in a area occupied by a living being, the spell fails.  If the caster chooses to have the lifting gas appear inside of a container that can hold it, it will fill the container up to the amount it can hold, but will not damage the container by overfilling it; any excess lifting gas is wasted (not created).

Note: lifting gas can lift 50 lbs per 1000 cu. ft.  Lifting gas is invisible and non-flammable.  Lifting gas is not breathable. A creature that needs to breath and is stuck in a container filled with it must hold their breath (see rules for holding breath and drowning).

Know Altitude
Divination
Level: 1 Bard, 1 Drd
Components: V, S
Casting Time: 1 standard action
Range: Personal
Target: You
Duration: Instantaneous

You instantly know your current altitude.  This spell may not work in extraplanar settings.