Occult systems of knowledge, at least those in European traditions, have a huge affinity for symbols.  For instance, astrology has the stars, the zodiac, the planets, and the aspects; Tarot has its 78-card deck; qabbalah has its sephiroth and paths and names of God and gematria.  Sometimes these symbols in different systems can be corresponded neatly (or not-so-neatly) with each other, much as different metric units can be converted into each other by reducing them down to a particular set of units.  Geomancy, with its sixteen geomantic figures, is no exception, and has connections to the planets, the elements, and so forth.  Nifty figures, them.  You might be interested in reading up about them if you’re so inclined.

Unlike other occult systems of knowledge, however, geomancy doesn’t have a fixed or canonical order for the figures.  Tarot has the Major Arcana and Minor Arcana with their numbered cards and ranks and suits, which can afford some structured ordering, and astrology has the order of the zodiac signs plus the planets in geocentric order from or to the Earth.  Geomancy hasn’t held a specific or meaningful ordering of its own for the figures, which is a little confusing at first.  Sure, there are ways to order the figures, but there is no ordering of them of geomancy’s own design for its own benefit.  Every author seems to prefer their own order in every single text, though it usually borrows at least in part from astrology (either the order of the zodiac signs or the planets associated with the figures).

First, let’s make two terms clear from computer science: sets and lists.  A set is a collection of things with no implication of order, while a list is an ordered collection of things.  There is no notion of “first” or “last” or “next” within a set; something is either a member/included with the set, or excluded from the set.  On the other hand, lists impose an ordering on the things within itself, with there being a first thing, a next thing, and so on until we get to the last thing; every think in a list has an index, its position within the list.  While astrology, Tarot, and the like have lists for their symbols (the numbering of the cards in the deck, the planets from geocentrically furthest to closest to the Earth), geomancy has never really had a fixed list.  It’s more accurate to talk of sets instead of lists for geomancy, at least in its historical development.

Several common methods of ordering the geomantic figures that I’ve seen include:

• Binary ordering, where each geomantic figure is read as a number in binary.  As with the geomantic emblem notation, a line with two dots is represented as 0 and a line with one dot as 1.  Thus, Populus becomes 0000, which in binary is zero; Tristitia becomes 0001, which is 1; Via becomes 1111, which is 16; and so forth.
• Planetary ordering, where each geomantic figure is ordered by its corresponding planet.  This relies on the use of a particular order of the planets; I prefer the traditional Chaldaean order, moon-first (Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn).  I set the figures Caput Draconis and Cauda Draconis, ruled by the nodes of the Moon, at the end; for each pair of figures, I put the masculine/active/direct/waxing/rising figure first and the feminine/passive/retrograde/waning/setting figure second (e.g. Populus followed by Via followed by Albus followed by Coniunctio…).
• Zodiacal order, where each geomantic figure is ordered by its corresponding zodiac sign.  This is complicated by there being different zodiacal attributions to the figures, but I tend to stick with Gerard of Cremona’s system (as presented in his “On Astronomical Geomancy”), but I know other geomancers use Agrippa’s system (such as John Michael Greer).  This is further complicated when several figures are assigned to the same sign; some authors (like Gerard of Cremona) simply set them next to each other without care for order, while others (like JMG) place them at the end.
• Emblematic order, where each figure is ordered by its placement in a particular geomantic emblem.  Which of the 256 emblems you pick, however, depends on a particular purpose and other factors.

Personally speaking, I use either the binary ordering or Chaldaean planetary ordering, when I care to order them at all.  Do you guys care about imposing an order on the geomantic figures, or do you care?  Does the notion of a list versus a set of geomantic figures matter in your work?