For purposes of the GAME distances are basically one-third with respect to
spell and missile range from outdoors to indoors/underground situations.
Thus most ranges are shown as inches by means of the symbol “, i.e. 1“,
etc. Outdoors, 1” equals 10 yards. Indoors 1” equals 10 feet. Such a ratio is
justifiable, to some extent, regardless of game considerations.

Actual effective range of an arrow shot from a longbow is around 210
yards maximum, in clear light and open terrain. Underground, with little
light and low ceilings overhead, a bowshot of 210 feet is about maximum.

Archery implies arching arrows. Slings are in this category as are hurled
darts and javelins, all arching in flight to achieve distance. Crossbows are
a notable exception, but under the visibility conditions of a dungeon
setting, a yards to feet conversion is not unreasonable.

Magic and spells are, most certainly, devices of the game. In order to
make them fit the constrictions of the underground labyrinth, a one for
three reduction is necessary. It would be folly, after all, to try to have such
as effective attack modes if feet were not converted to yards outdoors,
where visibility, movement, and conventional weapons attack ranges are
based on actual fact. (See MOVEMENT.)

Distance scale and areas of effect for spells (and missiles) are designed to
fit the game. The tripling of range outdoors is reasonable, as it allows for
recreation of actual ranges for hurled javelins, arrows fired from
longbows, or whatever. In order to keep magic spells on a par, their range
is also tripled. IT IS IMPERATIVE THAT OUTDOOR SCALE BE USED FOR RANGE
ONLY, NEVER FOR SPELL AREA OF EFFECT (which is kept at 1” = 10’) UNLESS
A FIGURE RATIO OF 1 :10 OR 1 :20 (1 casting equals 10 or 20 actual creatures
or things in most cases) IS USED, AND CONSTRUCTIONS SUCH AS
BUILDINGS, CASTLES, WALLS, ETC. ARE SCALED TO FIGURES RATHER THAN
TO GROUND SCALE. Note that the foregoing assumes that a ground scole
of 1” to 10 yards is used.

Movement scale is kept as flexible as possible in order to deal with the
multitude of applications it has, i.e. dungeon movement (exploring and
otherwise), city travel, treks through the outdoors, and combat situations
arising during the course of any such movements. Your referee will have
information which will enable him or her to adjust the movement rate to
the applicable time scale for any situation.
 

Fharlanghn (god of distance)
 

Q: What does the inch sign (?) mean in reference to distances and
length?

A: When discussing height or small items, it means inches. When
discussing spell ranges, missile ranges, and spell areas of effect
indoors, it means 1" = 10 feet. When discussing spell ranges and
missile ranges outdoors, it means 1" = 10 yards (30 feet); however,
areas of effect for spells are always measured in tens of feet, never
tens of yards.
(76.64)

Q: The spells? areas of effect listed in
the Players Handbook have got to be
incorrect. The lower water spell, for
example, has an area of effect of a
1" × 1" square per level of the caster.
Surely a cleric can affect more water
than one square inch.
A: The area is measured in scale inches.
One scale inch equals 10?, and one scale
square inch equals 100 square feet. Remember
that the areas of spell effects
never get larger outdoors, although ranges
do get larger (see page 39 in the Players
Handbook).
(153.7)
 

Q. What do 'inches' mean when given
in the rules?
A. The exact meaning of the term
'inches' varies throughout the rules,
depending on context.
    Ranges for both missile fire and spell
casting are given in inches. The meaning
of 'inch' in this context depends on
where the missile or spell is being
used. Inside structures (eg a dungeon)
1 inch equates to 10 feet.
Outdoors, 1 inch represents 3
times this distance -- 10 yards.
    Regardless of where the spell is cast
the area of effect remains the same
-- 1 inch always represents
10 feet.
    Movement rates are more complicated.
for mapping movement in a
dungeon setting, 1 inch represents
10 feet per turn.  For movement
through areas which are not being
mapped 1 inch represents 10 feet per
1/5 turn. In combat (or when fleeing)
movement is based on 1 inch equals
10 feet per round.
    Movement rates also apply to other
situations.  When adventuring across
wilderness terrain, and using the
standard mapping scales, 1 inch
represents 1 mile per 1/2 day of
travelling.  In a city context 1 inch
represents 10 feet per round (if
characters are not mapping).  Finally,
movement rates while flying roughly
work out at 3 inches representing
1 mile per hour.
(Imagine #3)