Presentation on theme: "6 December 2007 Intro to GIS GCSU Geography Research Performed by : Dr. Jeff Blick GIS Analysis/Presentation Performed by: Hope Hopkins."— Presentation transcript:
6 December 2007 Intro to GIS GCSU Geography Research Performed by : Dr. Jeff Blick GIS Analysis/Presentation Performed by: Hope Hopkins
To perform a GIS analysis on Pre-Columbian Settlements found on San Salvador Island in the Bahamas. The purpose of this analysis will be to: help identify abundances in particular ecological sites use spatial references to establish a Settlement Pattern Analysis both will help with Anthropological questions and also with the indication of the location of future sites.
Put on Different Layers Prehistoric Sites (Red Dots) ‘prehistoric_sites’; 556-1500ADHistoric Sites (Yellow Dots) ‘colonial_sites’; late 1700s-1900AD Total Land Area of Island (sq.km) 163km2? Settlement Pattern Analysis Prehistoric site density per 1500 meters (approx. 1 mile) Distance Between Sites Point Distance Buffer Analysis to Indicate What Resources are Within the Radius 500m 1000m 1500m Trends in vegetation or marine ecosystems indicating locations of future unexcavated sites. Site Proximity of 1500m Agriculturally Disturbed Area (Soil Fertility?) Freshwater Wetlands Lake or Pond?
1. Load archeological_sites from X:\DATA\Bahamas\featureclasses 2. Use selection menu to select features including those classified as ‘prehistoric’ 3. Export data to create new layer and shapefile titled ‘prehistoric_sites’ 4. Deselect features 5. Select attributes for ‘colonial sites’ 6. Export data to create new later and shape file title ‘colonial_sites’
Total Land Area: Previously calculated as approximately 163km2 New calculation performed at request of Dr. Blick for actual land area estimate excluding tidal creek, lakes and wetlands Result: Approx. 94km2
Add Data for ‘prehistoric_sites’ Add buffer using analysis tools, proximity, buffer- 1500m Add shapefiles as necessary Ex: ‘vegetation’ Identity tool Analysis tools, overlay, identity Enter properties file of shapefile and under symbology- Categories, value field-’type’
After creating the new layers for Pre-Historic sites and Colonial Sites, various applications were used with the ‘prehistoric_sites layer’ and shapefile. The total land area calculated excluding wetlands, lakes and tidal creek is 94km2. Using ‘Spatial Join’, the number of sites within 1500m of one another, averaging 3 sites per 1500m Buffers indicate resources within a 1500m area. Using ‘near’ function, distances between sites and other sites were noted: Avg. Distance= 979m Avg. Shortest Distance=844m Pre-Historic Sites showed the trends: Located within 1500m area of agriculturally disturbed areas, perhaps an indication of soil fertitlity Located within 1500m area of marshes Located within 1500m of water resource-lake or pond, particularly ponds as they are more numerous in dispersion. There is much more research to be performed- The analysis of this information more thoroughly could answer many question about the past.