An important note about the construction of the data layers: as you may have already noticed, only a portion of the Early Classic Period sites in the Marana Community are used in this analysis. We include only habitation and rockpile field sites from Zones 2 and 4 (see Figures 2 and 3) to simplify the construction and interpretations of the exercise.

The decision to separate Zone 2 sites and their associated ecological variables from contemporaneous sites and variables in Zone 4 was based on archaeological interpretations suggesting that the Classic Period occupants of the two zones employed different subsistence strategies. Interestingly, Zone 3, between Zones 2 and 4, is relatively free of rockpile fields and habitation sites (Figure 2). This distribution supports the idea that the two zones above and below Zone 3 were distinct in some meaningful fashion in the conceptual frameworks of prehistoric farmers. Ultimately, by treating Zones 2 and 4 as separate units of data, we have left it for you to decide for yourself whether or not the spatial data lend support to this hypothesis.

Separate polygon themes were created to represent the ecologically viable regions for agave growth for each of the two zones. In each zone, the rockpile field sites at the highest and lowest elevation, as well as with the steepest and most gentle slopes were recorded. The extreme elevation and slope ranges obtained from known archaeological data were then used to create polygons that include all known rockpile field sites as well as other areas of comparable elevation ranges AND slope ranges that could have possibly supported agave, given our knowledge of known prehistoric fields.

The final theme, , provides a simplistic model highlighting which other areas might be suitable for agave cultivation, given the measured ranges of two basic ecological characteristics (elevation and slope) of archaeologically known Early Classic Period rockpile field sites in Zones 2 and 4. By definition, then, it includes all known rockpile field sites. There may be rockpile fields that have gone unnoticed by, or that were destroyed prior to, investigation that this model cannot take into account. In other words, is our best approximation based on all available data. This situation is one with which researchers must live when conducting spatial studies of this nature, because, unfortunately, one can never acquire ALL pertinent data due to financial constraints, visibility problems, and/or time's detrimental affect on archaeological remains.