It's never been clearly defined how much time a standard action takes. A round takes 6 seconds, and at Earth gravity, an object will fall about 170 meters, or about 600 feet, in that time. If you assume that a standard action takes about half of that time, or three seconds, that would be about 1/4 as great a distance.
I think LazarX is correct that glide is not intended to substitute for feather fall.
Maybe it was 3.5 rules, but I remember someone finding a rule that mentioned how high up you must be to cast a standard action without hitting the ground.
Couldn't you move action jump, standard cast the spell?
You could cast it while already feather falling to get some sideways movement in - though that seems mostly useless. But then a spell that does nothing if cast while touching the ground but which takes a standard action is pretty useless anyway.
I could see that but it apparently has to be cast when you are in freefall, as it states that the spell ends when your feet touch the ground regardless of duration. That would mean that the minimum safe downward distance for this spell would be around 160 feet unless you can leap of the edge just as you are completing the spell..It's never been clearly defined how much time a standard action takes. A round takes 6 seconds, and at Earth gravity, an object will fall about 170 meters, or about 600 feet, in that time. If you assume that a standard action takes about half of that time, or three seconds, that would be about 1/4 as great a distance.
I think LazarX is correct that glide is not intended to substitute for feather fall.
As far as I can tell, that's exactly the intended use.
It could be used towards the end of a fly spell to give you more time and distance in the air.
I feel this is a horribly conceived spell. You move downward at the rate of Feather Fall (60'/rnd). The spell has a duration of 1 minute/lvl, but ends as soon as you touch the ground. How often will any character ever even get 1 minute of the duration (having to fall a full 600 feet!)? Earliest entry to this spell gives a 3 minute duration, for 1800 feet of downward motion. Is that EVER going to happen in a game!? The ONLY advantage I see is the ability to move 5 feet in any horizontal direction for ever 1 foot of vertical descent. Figuring the likelihood of, say, a 100 foot fall, that's 500 feet of horizontal movement over the course of 2 rounds (300 ft for the first 100 ft descent, 200 ft for the last 40 ft descent).
This spell is SO circumstantial, it's (quite frankly) stupid! At least they could have designed it so the duration is a flat 1 minute/level (dismiss-able) that does NOT end upon contact with the ground! Heck, even 1 round/level (D) without that restriction would have been better! With a 1 rnd/lvl (D) duration, at the lowest entry to this spell, that's 3 rounds = potentially up to 180 ft worth of descent with up to 900 ft of horizontal movement. It's a circumstantial escape method.
Frankly, I feel this should have been a 1st level spell, modeled as follows:
Glide
School: Transmutation
Level: druid 1, ranger 1, shaman 1, sorcerer/wizard 1, summoner/unchained summoner 1, witch 1
Elemental School: Air 1
Casting Time: 1 standard action
Components: V, S, M/DF (a leaf)
Range: Personal
Targets: you
Duration: 1 minute/level (D)
Becoming as light as a leaf on the wind (insert Serenity jokes here), you float one foot above the ground. You may move horizontally at a rate of 30 feet as a move action (20 feet with medium or heavy encumbrance), and may take an ground based movement you would otherwise be allowed while this spell is in effect, albeit at this movement rate. No effects which increase movement speed affect the movement speed of this spell. If at any point in the spell's duration you find yourself falling, you descend at a rate of 20 feet per round.
If you are under the effects of Levitate, as well, you can choose to not descend during a fall. In this situation, you can choose to move horizontally without descent, move horizontally with a descent of your choosing (up to 20 feet per round), or ascend vertically as per the Levitate spell. You may not move ascend vertically (per Levitate) and horizontally (per Glide) in the same round.
As with Levitate, this spell makes you very unstable, and you suffer all combat penalties associated with Levitate while under the effects of Glide. The penalties from Glide and Levitate are not cumulative.
While under the effects of Glide, you are very susceptible to effects which force you to move or alter your positioning. You take a -5 penalty to CMD against bull rush, drag, reposition, and trip attempts made against you, a -2 penalty to all reflex saves made against area spells, and a -5 penalty (not cumulative) to reflex saves made against wind-based spells. You are vulnerable to such spells and effects, taking double the effect, where applicable. When affected by spells and effects which affect flying creatures (such as Gust of Wind), you are treated as two size categories smaller (in addition to the aforementioned vulnerability).
Characters may start and stop horizontal movement without penalty, but any change in direction requires a Fly check at poor maneuverability. Failure indicates no movement can be performed, you are treated as flat-footed, and a standard action requiring a successful Fly check (again, at poor maneuverability) is required to regain your bearing (and no longer be flat-footed).
I think its supposed to be less of a "weaker featherfall" and more of a "horizontally oriented weaker levitate." You get to a high point, cast it, jump down, and glide across to where you are going. Like accessing rooftops of tall buildings, or going from the top of a chasm to a cave on the other side.
From the PRD
A character cannot cast a spell while falling, unless the fall is greater than 500 feet or the spell is an immediate action, such as feather fall. Casting a spell while falling requires a concentration check with a DC equal to 20 + the spell's level. Casting teleport or a similar spell while falling does not end your momentum, it just changes your location, meaning that you still take falling damage, even if you arrive atop a solid surface.