Geography, Spatial Data Analysis, and Geostatistics: An Overview

Geostatistics is a distinctive methodology within the field of spatial statistics. In the past, it has been linked to particular problems (e.g., spatial interpolation by kriging) and types of spatial data (attributes defined on continuous space). It has been used more by physical than human geographers because of the nature of their types of data. The approach taken by geostatisticians has several features that distinguish it from the methods typically used by human geographers for analyzing spatial variation associated with regional data, and we discuss these. Geostatisticians attach much importance to estimating and modeling the variogram to explore and analyze spatial variation because of the insight it provides. This article identifies the benefits of geostatistics, reviews its uses, and examines some of the recent developments that make it valuable for the analysis of data on areal supports across a wide range of problems.     

An evolutionary model of social change in the Middle Ohio Valley: Was social complexity impossible during the late woodland but mandatory during the late prehistoric?

We present an evolutionary model of social change in the Middle Ohio Valley during the Fort Ancient period (AD 1000–1650), primarily relying on an application of Winterhalder’s (1986) and Kelly’s (1995) evolutionary ecology model of cultural responses to environmental variability. We predict changes in social organization, political complexity, and patterns of stylistic similarity. As the environmental background for our model we employ recently published moisture data. By iteratively applying the synchronic Winterhalder–Kelly model we are able to predict a sequence of general trends that agree with much current interpretation of Fort Ancient development. Specifically, the model leads us to expect increasing village size, the development of regional traditions, and the development of leadership roles and a region-wide style Horizon around AD 1400. However, our model provides the ability to make testable predictions that deviate from the accepted cultural history and predicts that the Middle Ohio Valley and the groups referred to as Fort Ancient were far from homogenous.     

Morphometric identification of bovid metapodials to genus and implications for taxon-free habitat reconstruction

Principal Components Analysis (PCA) of measurements on twelve metacarpal and ten metatarsal dimensions indicates that metapodials differ much more in size than in shape among the twenty-three genera of extant Sub-Saharan bovids. The only conspicuous shape variation is in metapodial length, which sometimes differs significantly among genera that are similar in all other dimensions. It follows that Discriminant Analysis (DA) intended to identify metapodials to genus will depend primarily on size, and except for the occasional like-sized genera that differ in metapodial length, DA will often confuse genera of similar size. DA of the same metapodials subjected to PCA supports this prediction. PCA further shows that bovid species that favor the same habitat often differ in metapodial size, shape, or both, and species that favor different habitats often overlap substantially in their metapodial morphometrics. DA intended to assign metapodials to habitat will thus produce different results depending on the species used to characterize each habitat type and on the number of specimens by which each species is represented. Habitat reconstruction founded in DA is therefore taxon dependent rather than taxon-free, and it cannot supplant reconstruction based on taxonomic identifications below the family level.     

Distinguishing between archaeological sheep and goat bones using a single collagen peptide

We describe a method of isolating and analyzing a single collagen peptide able to distinguish between sheep and goat bone collagen. The 33 amino acid peptide from both sheep and goat collagen was sequenced and shown to differ between the two species at two positions. Analysis of a range of caprines indicated that the sequence changes occurred between the divergence of the Himalayan tahr (Hemitragus jemlahicus) and the ibex (Capra ibex) and that the proposed goat marker is diagnostic of all Capra species and breeds. The survival of these markers in archaeological bones was tested using a set of 26 ovicaprid specimens from Domuztepe, a Neolithic site in south central Turkey. These markers were used to test the osteological determination of 24 of the Domuztepe bones, and determine the species for two immature specimens. The collagen-peptide method has advantages over other non-morphological methods of sheep/goat distinction because of the long-term survival of collagen over other biomolecules such as ancient DNA. The results also highlighted the problems in relying upon one morphological criterion, in this case on the distal radius, to distinguish between sheep and goat bones.     

GIS-based modeling of drought and historical population change on the Canadian Prairies

This article describes the development of a GIS-based model of historical drought and population change in western Canada, designed to support qualitative field research into drought adaptation and migration. The model combines digitized census data and recently available modeled historical climate data at a 10 km² grid cell scale and can be used to generate maps of ‘hotspots’ where historical declines in rural populations may be associated with extended periods of heat and lack of precipitation. The results suggest a promising avenue for expanding and refining GIS-based modeling of historical human–climate interactions to support qualitative research and to potentially serve as a stepping stone toward forecasting future risk areas of drought-related migration in continental dryland areas.