Distribution Mapping

What distribution maps can do

-plot sites, features or artefact locations in space/time

-plote events in space/time

-suggest pathways of movement> suggest histories of movement

-suggest pathways of communication and influence

-suggest correlations between different variables

Sources of bias in distribution maps

-sampling effort: location of universities or other kinds of research institutions, homes of fieldwalkers and metal detectorists, any activity that gives focus to some parts of the landscape and not others

-things inherent in the landscape (Schiffer’s N-transforms): becomes problem when not destroyed evenly

-sometimes maps hide more complexity, always questions not being asked, can be distorted by metrics and scales people use

Distribution maps- definition

-refer broadly to maps on which the location of some element is mapped, usually as a point or dot, in order to visualize wider trends over larger area

-useful in visualising density, or distribution, of instances of an element within a given area

Distribution maps in archaeology

-archaeology has adopted them as ways to visualize and analyze distribution of items of arch interest like built features, artifacts, natural features, etc

-maps can then be compared and further analysed to represent variety of relationships between points like hotspots in human activity, intervisibility of features, networks of movement, etc

-with prevalence of GIS and other quantitative approaches to arch, increasingly useful tool for modeling and analysing data within landscape archaeology

-encourage new ways of thinking about space and place

‘Deep mapping’ approach to distribution mapping (Earley-Spadoni 2017)

-’deep mapping’ in the digital humanities: multilayered, digital cartographic representation

-multi-media elements and super-imposing layers

-allows for dissent, discussion, and multivocality regarding contested geographies

-in contrast in arch geospatial technologies used almost entirely as analytical or data capture tools rather than exploratory approach

Literary GIS (Cooper and Gregory 2010)

-interdisciplinary ‘mapping the Lakes’ project in which GIS used to explore relationships between two textural accounts of English Lake district

-authors: Thomas Gray and Samuel Taylor Coleridge

-digitized texts, place-names identified and tagged, coordinates found for each reference, converted into GIS

-includes exploratory maps like ‘mood maps’ where map moods in writing, critical analysis

-however things excluded from maps, Cartesian reduction of experience of space, makes it hard to convey sense of physical movement

Types of scale in archaeology (Harris 2006)

-cartographic scale: level of abstraction at which a map is constructed and relative correspondence to reality

-methodological scale: scale selected by researcher in order to garner info necessary to pursue a research problem

-geographical scale: overarching spatial extent of study lain over these scaled landscapes

small scale/ large scale can refer to both coarse/fine scale and large/small area

Modifiable Areal Unit Problem (Harris 2006)

-differing outcomes can be obtained by aggregating areal units in different ways

-happens when data assigned to arbitrary areal units that form base spatial units for study and aggregated into larger arbitrary units

-consists of three problems: scale problem in which question as to number of zonal units needed for a study, aggregation problem, impact of ecological fallacy (makes inferences from coarse to fine, eg from population to individual)

-real life example: gerrymandering

Portable Antiquities Scheme (Robbins 2013)

-since 1997 recorded over 860,000 objects in an online database

-have been recovered by general public across England and Wales

-date from Palaeolithic to early modern era

-used by academics in over 350 projects

Robbins (2013) seven-stage categorisation of collection bias

-deposition: either deliberate burial or accidentally lost, some items easier to lose/harder to recover so more prevalent

-preservation: affected by both material of object and physiochemical conditions of surrounding environment

-survival: may not survive to present due to environment and removal

-exposure: to be “exposed” must be in position from which it can be perceived by collector, depends on artifact’s position and technique used to detect it

-recovery: dependent on arch factors, visual apparency, etc

-reporting: dependent on whether finder wishes to report it, knows where to report it to, etc

-recording: bias introduced when only some finds recorded

PAS case study: Isle of Wight (Robbins 2013)

-669 artefacts recorded on PAS, bulk recovered by independent detectorist and a detecting club

-bias because individual collected much of finds and focused on just one area

-metal detectors don’t find all artifacts or work on all terrain

-’home range’ effect: both practical and based on interest in area where you live

-can only collect on 27% of total land, biased collecting

-hard to know if everything has been reported

Problems with arch maps (Green 2018)

-many archs forced to make maps as part of their projects or employment, but little expertise in good cartographic practice, tend to learn through trial and error

-common practice: to map all the sites mentioned in the text and call it a day

-practically useless, distribution of all sites of the same type should be included, not just those the author wanted to write about

Post-modernist critique and response (Green 2018)

-maps seen as tool of positivism

-provide top-down perspective at odds with lived experience

-yet recovery of lived experience of the past not possible anyway

-can be very useful when principles of ‘good’ map design are followed

Maps and the Uncertainty Principle (Green 2018)

-uncertainty principle in quantum mechanics: the more accurately you try to measure the position of the particle, the less accurately you can measure its speed

-for arch: the greater precision one can discover about one aspect of an element on a map, the less precision one can discover about another aspect of an element on a map

-ex: spatial scale vs. spatial resolution: when working on a broad scale dots placed on a map will often cover many kms of space, low spatial precision

EngLaId Project (Cooper and Green 2016)

-5-year research project based in Oxford

-aims to produce history of the English landscape from 1500 BC to AD 1086 using digital and published data from across English Archaeology

-analysis of evidence available at nationwide level interwoven with more specific studies of the material from 14 widely distributed regional case studies

-exploring themes incl identity, forcefulness of nature, community and change, making place

-also exploring character and interpretative capacity of various digital datasets

EngLaID data (Cooper and Green 2016)

-almost 1 million text-based digital records amassed formally in a database

-in small case studies integrated datasets manually

-for larger scales used GIS spatial binning techniques in which apply coarse gridded mask across data points, record presence/absence of object of particular period and type for each cell in mask

-end result virtually indistinguishable from manual integration

-difficulty: large number of variant terms for similar sites

‘Characterfulness’ of data (Cooper and Green 2016)

-have diverse histories, contents, structures, and are riddled with gaps, inconsistencies, and uncertainties

-many of the decisions that archaeological curators make in the handling of their data not black and white

-usefulness of turning to how strategies might be developed for employing intricate archaeological data ‘as if’ they are accurate

Settlement of Actuncan, Belize (Fulton 2019)

-Maya settlement in Belize

-during Late Classic Xunantunich became established as provincial political center, Actucan likely subordinate center

-Xunantunich experienced demographic decline and abandonment during Terminal Classic, political resurgence of Actuncan

-remained viable center into the Postclassic

Actuncan: methodology (Fulton 2019)

-focuses on three patio-focused residential groups Northern Settlement area: Group 1, 5, and 6, all occupied during Terminal Classic

-Group 1: large-scale excavations conducted previously, repeatedly used burials

-used clam-shell style posthole diggers on along predefined grid to systematically collect overlapping datasets of macroartifacts, microartifacts (less than ¼ inch), and soils for multielemental analysis

-plotted and analyzed distribution of over 2000 macroartifacts and 74 microartifact samples

Actuncan: results and implications (Fulton 2019)

-large deposition of Manganese and Phosphorus in group 1 associated with food activities, may have been used for ceremonial feasting

-also had higher macrofact and microartifact levels

-may indicate locus for specialized activities/focal residence

-shared practices at Actuncan could have helped reinforce social ties, community affiliation

Allen Site: Overview (Bamforth et al. 2005)

-Paleoindian campsite in SW Nebraska, occupied for >3,000 years

-first excavated in 1940s, much of data comes from then, very good stratigraphic provenance for many finds (although not unmodified bone)

-over 13,000 unmodified flakes, other finds

-diversity of artefacts and number of hearths indicates residential camp

Allen Site: Methodology (Bamforth et al. 2005)

-generated all distribution maps in using Surfer software package

-examined vertical patterns of conjoined artifacts to assess degree of postdepositional processes

-horizontal distribution of artifacts within each SU, plotting horizontal patterns of artefact counts per grid square, size per grid square, horizontal patterns of connections among refitted artefacts

-compared with ethnoarchaelogical studies, intrasite analysis with other paleoindian sites

Allen Site: results (Bamforth et al. 2005)

-artefacts and features scattered throughout levels

-limited postdepositional disturbance

-hearths and artefact concentrations show almost perfectly mutually exclusive distributions

Allen Site: implications (Bamforth et al. 2005)

-ethnoarchaeology: domestic areas kept clean of dangerous, inconvenient, or messy debris, trash and debris accumulate outside, hearths in these areas used for non-domestic hearths

-Allen site: prob trash heaps, site used frequently enough that heaps from previous occupation would still be visible, hearths made around trash rather than vice versa, peripheral to domestic (hearth≠domestic)

-intrasite: Paleoindian HGs usually viewed as moving unpredictably and nonrepetitively, eg at Bison kill-sites

-Hell Gap in Eastern Wyoming: also occupation over long range of time, important source of flakeable stone that dominates assemblage (use of local stone at Allen Site as well)