Catchment Area Analysis in the Valley of Oaxaca

The final project for applications in archaeology involved a research project, the default being a catchment area analysis for a portion of the Oaxaca Valley. Estimates were made of collection unit populations for various periods in a given set of (digitized) grids from the Valley of Oaxaca Settlement Pattern Project performed by Blanton et al. in the late 1970s. From these, an estimated target yield for maize production needed to satisfy food security for these populations was arrived at and compared to an estimate of the maximum maize yield from a catchment area of 1 kilometer around each collection unit as generated by a buffer in ArcGIS.

Catchment Areas for Guadalupe Period

Catchment Areas for Early Monte Albán I

Catchment Areas for Late Monte Alán I

Catchment Areas for Monte Albán II

Land Cover Classification Analysis

This week's maps were produced by running spatial analysis tools to run, first an unsupervised raster classification on an ortho-rectified aerial photo and then a supervised raster classification (wherein a point file was created that identified various points in the raster as having a particular classification. The goal of this would be to create high contrast classes of land cover in aid of using remote sensing as an archaeological prospection tool.

The results indicate that while this type of analysis may be helpful in the right circumstance and with the right kind of data, it is not necessarily the most useful approach. Land classes need to be differentiable enough to prevent mixed classes that cross different classes, causing the resulting classification scheme to obscure more than reveal.

Unsupervised Raster Classification

Supervised Raster Classification

3D Modeling for Archaeology

This week's assignment involved composing interpolated subsurface soil layers (interpreted as the interfaces between topsoil and cultural layers, then cultural and natural layers) from shovel test data. From a point shapefile of shovel tests with the depths to cutural and natural recorded as attributes, depth lines were composed for each test location in ArcScene. The data was also used to create Inverse Distance Weighted surfaces in ArcGIS that were then transferred into ArcScene and extruded to the correct depths.

Also, a flythrough video was generated through the depth lines of the shovel test points.

shovel tests

interpolated layers

depths of proposed fence posts calculated from IDW surfaces.

Using Surface Interpolation to interpret Archaeological Survey Data

This week's assignment went over the details and intricacies of importing various types of survey data into ArcGIS and performing spatial analyses upon them, specifically surface interpolation of artifact density patterns. Various types of interpolation were performed on two sets of data, one on the scale of a occupation site where shovel tests were performed across the site and a second on a regional scale looking at the density of collection areas.

The work focused on the nuts and bolts of performing the analyses and did not touch on, nor explain much of, how best to chose analysis methods and the parameters thereof to provide an accurate and useful analysis.

Various interpolation method examples shown across two regions at variable scales.

Digitizing Archaeological Datasets

This project spanned two weeks and was rather intensive. Scans of survey grids from the Oaxaca Valley Settlement Survey Project were georeferenced and the spatial data from the surveys were digitized into attribute tables of shapefiles. The task of georeferencing was made difficult by the poor quality of the scan of the survey grid and also by difficulty in finding a suitable basemap of the Oaxaca Valley onto which to rectify the grid. Eventually a solution was found, though, and the grid was tied in. Afterwards, the separate grids for land cover and collection surveys were tied into the grid and then their data was digitized. Finally, each grid was laid out with land cover and survey results and a map was created, or three in the case of Grid N2E3, which had 3 grids of survey collection data due to the density of occupation.

Grid Locations

N2E3a

N2E3b

N2E3c

N2E4

Georeferencing 1785 Map of Macao

This week the assignment involved georeferencing (as best as possible) an historic map. While the map couldn't be georeferenced with utter precision, using a spline algorithm, it could be placed well enough to provide a recognizable regression from the current state of the area.

Macao, 1785

Dress Rehersal for Presenting Historic Maps

This week's assignment was simple. We were given a raster of an historic, late 19th Century topographical map of coastal Massachusetts that was already mosaicked and geo-referenced. From this, a basic map was created that showed the Boston area, located Paul Revere's home and presented Revere's portrait and a census record from his household recorded in 1790.

Paul Revere's Home

The map produced this week was based on data pulled form MEGA Jordan, an online spatial database for Jordanian archaeological sites. This resource was designed and implemented in order to aid in the management of archaeological and heritage resources in Jordan, is based on free and open source software and, being well supported by the government of Jordan is comprehensive and responsive. All in all it seems to be an excellent resource for heritage management.

This week's course content also touched on the ethics involved in maintaining archaeological databases (as well as other types of archaeological resource output). As recorded data is often all that is left of an excavated archaeological site, data protection is critical to preserving the archaeological record. Also, site protection and preservation requires that archaeological databases, spatial or otherwise, be kept secure, especially for vulnerable sites.

Jordanian Archaeological Sites

The first assignment for Applications in Archaeology involved creating a map of Chicago that showed the extent of the 1871 fire as well as landmarks that pre- and post-dated the fire. Much of the assignment focused on performing attribute queries as well as clipping layers.

The Impact of the Great Chicago Fire of 1871