Working with GIS

GIS

geographic informational system lets us visualize/analyze spatial data to understand relationships/patterns/trends

• shows the world as a stack of layers where each layer represents a specific feature

ESRI

Environmental Systems Research Institute

• industry leader of GIS software and geo-database management

• ESRI ARCGIS is a software package that is the industry standard for GIS analysis, used to make maps

Dr. John Snow case

Spatial analysis of people infected with cholera during an outbreak in London

• found a dense cluster around a contaminated pump

Key uses of GIS in archaeology (6)

Can ask questions about migration, landscapes, people, and settlements over time because archaeology is fundamentally spatial

• GIS provides tools to visualize and interpret the past in context

• GPS and drone data can feed into GIS data

6 uses

1. site/landscape mapping: locating a site within a landscape, environmental data (terrain, land cover, etc.), and cultural features (ancient roads, structures, field systems, etc.)

2. cultural heritage management and preservation: document, protect, and make decisions about archaeological resources; identify threat, looting patterns, erosion risk, etc.

3. survey planning and predictive modeling: creating excavation grids for survey and identifying high-probability sites for excavating

4. excavation mapping: mapping features, artifacts distributions, and spatial relationships

5. 3D reconstruction: terrain models, site morphology, and architectural visualization

6. detecting change: using historical maps and satellite or arial imagery to understand how a place changed over time

Examples

• tracks migration over time (i.e. across Indo-European routes)

• detects change over time (i.e. the shrinking of the Aral sea

• maps heritage and culture (i.e. interactive native lands map)

• tracks historic trade networks (i.e. Roman routes and Mediterranean trade)

• maps demographic data (i.e. US socio-economic status by county)

• maps ecosystem and landscape across the globe

Vector

points, lines, and polygons that represent discrete features in an attribute table. with limitless data

• points as (x,y) coordinates and lines as a series of connected points

• all depends on scale of the map

Raster

a grid of pixels or cells that show continuous data (i.e. 1 pixel = 1 value)

• cells can be numerical (e.g. elevation, precipitation, and temperature) or categorical (e.g. land cover)