Site Report - Valley of Oaxaca

For my final project, I chose to revisit the Valley of Oaxaca dataset from a previous module assignment. I used the soil and site data from the grids N6E4, N6E5, and N6E6 to test a hypothesis concerning the rise of the Zapotec state. If population pressure was exceeding the regional carrying capacity, we would expect to see phases where the population is much greater than could be supported by agricultural yield estimates in their catchment circles. I completed this analysis with the help of ArcGIS products. Here is a basic outline of steps I created for myself to help with the         analysis process.

Methods:

1) Determine time periods to use and make into separate layers.

     - 4 time periods total

2) Buffer the sites with a 2 kilometer radius with the Buffer tool.

     - Make sure buffers are set to dissolve all.

     - 4 buffer outputs total

3) Convert the site polygons into point features using the Feature to Point tool.

     - 4 site point feature outputs total

4) Use the site points to create Thiessan Polygons for each time period.

     - 3 Thiessan Polygons total

5) Combine the site buffers with the Thiessan Polygon outputs using the Intersect tool.

     - 3 intersects total

6) Edit the intersect outputs, snapping the edges of the Thiessan polygon to the buffer and grid boundaries.

     - 3 edits total

7) Clip the soil type to the newly edited intersect outputs with the Clip tool.

     - 9 clips total

8) Calculate area in hectares of soil clips using the Calculate Geometries function.

9) Perform a spatial join between the clip layers and point file data.

     - This combines the population data with the land area data.

Based on these results, I was able to determine if the population of each site could subsist on the amount of hectares available within their 2 km catchment radius. One adult human can subsist on a minimum of .5 ha of arable land. For ease of results, 1 ha will equate to feeding 1 human

The Rosario phase settlement had an estimated population of 10, and had 192 ha of Type I land and 451 ha of Type III all arable land. With only 10-20 hectares of land required for subsistence, the Rosario phase settlement would be able to support their population on Type I land and Type III land.

The Early I phase settlement had an estimated population of 185, with 220 ha of Type I land and 1507 ha of Type III all arable land at their disposal. They would require 185 to 370 ha at most in order to sustain their population. Based on the amount of each land type available to them, they should have been able to support their population on Type I and Type III all arable land.

The Late I phase has an estimated population of 941, with only 220 ha of Type I land available, 415 ha of Type III 10% arable, and 1834 ha of Type III all arable land. They would require 941 to 1882 hectares of land at most in order to sustain their population. In terms of yield productivity, they would not have enough Type I or Type III 10% arable land to sustain their population. There would be enough Type III all arable land, but productivity and yields would not be as reliable as Type I land. 

The Monte Alban II phase had an estimated population of 774, with only 220 ha of Type I land and 1579 ha of Type III all arable land available to them. They would require 774 to 1548 hectares at most in order to sustain their population. They would not have been able to produce enough yields with Type I land. They barely meet the requirements for subsistence on Type III all arable land, which was established as not having reliable yields.

Remote Sensing

For this assignment, we classified the site Monk's Mound, located in Cahokia, Illinois. Cahokia Mounds is the largest prehistoric earthworks north of Mexico and was inhabited from ca. 600-1400 AD. It originally consisted of 120 earthworks, but today is reduced to 80. It is estimated that around 40,000 people may have lived in Cahokia at its peak, yet the reason for it's decline is still unknown. Although there is little known about Cahokia, it is still an important national landmark.

Supervised classification allows you to choose how many classes you use and their general location. I made six classes based off of what I predominantly saw in the Cahokia TIFF image. There is still some slight error in the classification, but I had more control over classification than with unsupervised.

 Unsupervised classification automatically classifies areas for you based on the number of classes you desire. This one has eight classes, with almost every single one merging into the class of another (based off toggling back and forth between images). Unsupervised is prone to more error with a fewer number of classes specified.

3D Modeling

   In this module's lab, we used ArcScene to create a 3D representation of a shovel test site on the College Lake County Campus in Grayslake, Illinois.

Here is my fly-through animation showing the strata of the shovel test sites.

https://youtu.be/47pO8lqqLpg 

This image shows the geological layers belonging to each strata. The red-blue scheme is representative of high to low depth.

This image shows the cross section I completed of a proposed cable trench through the study area. The trench runs from the NW to the SE, in a diagonal line.

This is the map I made of the cross section for the proposed cable trench.

This is the map I made for the geological layers and their strata.

Surface Interpolation

In this lab, our objective was to utilize different types of interpolation methods and to compare and contrast their uses in varying site scenarios.

This was my extra deliverable as a graduate student. This poster shows 5 different maps using varying powers of IDW interpolation. The final map on the bottom right shows the power I felt best portrayed the settlement pattern of prehispanic peoples in coastal Ecuador. This map also uses contouring to highlight the areas with a larger population.

This poster shows the varying density maps I used to portray population density at the Barriles site.

This maps shows the varying density maps I used for the Machalilla site.

Digitizing, Module 6

   In this lab, we georeferenced old maps of archaeological sites and land cover to Oaxaca Valley, Mexico. In addition to that, we created shapefiles for and digitized the land cover and archaeological sites for each grid. Finally, we were to join tables of our digitized sites to a prepared excel file. My grids were N4E3, N4E4, and N4E5. 

This is a map of my three georeferenced grids. The most difficult part of this assignment was determining the grid locations. The historical topographical map I was georeferencing was especially blurry in the location of my grids, so you see that they do not line up perfectly.

 These next three maps show each grid and its digitized features. This part of the assignment was not difficult, but very time consuming. However, it was hard to read and determine the labels on some of the site features.

 This map shows the population estimate for a Monte Alban IIIB site in my N4E5 grid. The assignment was to find the most densely populated IIIB site cluster and symbolize it according to the low population field in the attribute table. However, I only had one IIIB site out of all my grids, with a low pop of 10. The site is located in an all arable land type, but is far from a river. I can only guess that even though it was on good land, it must have been isolated in some way from other resources.

Georeferencing, Mod 5

   In this lab, we georeferenced a historical map of Macao (present day Macau), created by explorer James Cook and published in 1785. Macau is located nearby Hong Kong, China and is a popular tourist location. The image was downloaded from the David Rumsey Historical Map Collection website. I georeferenced the historical map to a present day basemap by selecting control points on each map to connect to one another. The historical map is distorted due to 'historical' inaccuracies concerning actual island locations and present day differences. However, I based my control points off of still existing features, such as elevation points (with the help of a topography basemap), and was able to get the historical map to represent present day Macau as close as I could.

Historic, Module 4

   The purpose of this module was to acquaint us with online resources of historic information and how to locate and interpret historical records on these sites. In the lab we learned how to hyperlink the historical images seen on the map into a point shapefile of Paul Revere's house location in the city of Boston.

   This map was created for the purpose of illustrating historic Boston and the location of Paul Revere's home. Included on the map is an image of Paul Revere, a star point indicating his home location, and an image of a census count with his name listed on it. Below is a short description of who Paul Revere is and what he is known for. Also included is the URL to the Google Map location of his home in Boston.

Ethics

   This map shows Jordanian archaeological sites. The purpose of this module was to familiarize ourselves with ways to access site location coordinates, and how to use that information to make point locations in a map. Data for site locations was obtained from a publicly accessible site domain called MEGA, which is an archaeological site searchable database for the country of Jordan. While MEGA does provide site location, it also has varying levels of archaeological site information security based upon user identity. A guest to the site would have less access to site information than a user with administrative capabilities. Precautions like these aid in the prevention of site looting. 

   However, there is the concern that public domains like these and Google Earth give looters more accessibility to site location whereabouts, if not per say information about the sites. In retrospect,  this might in turn increase looting capabilities. Needless to say, site location sharing should be handled cautiously, considering there are now more ways than ever to view and find archaeological sites.

Module 2, Queries and Clips

   

   This lab implemented queries and clipping to show historical landmarks affected by the Chicago Fire of 1871, as well as the landmarks built in the twenty-year regrowth period afterwards. Also shown are the wards damaged by the fire and the starting point of the fire.