Aerial Photography for Archaeology

Monte Alban in southern Mexico

What are some of the advantages of aerial archaeology?

What are some of the platforms that have been used for aerial archaeology?

What are soil marks, shadow marks, and crop marks, and how are they used to find sites?

What are some of the difficulties encountered when using aerial imagery for archaeology?

Learning Objectives

How can aerial photography contribute to archaeological research?

“It is a common opinion that an aerial archaeologist is sitting in an aeroplane, trying to discover archaeological sites and to take a few nice photographs of them.” (http://www.univie.ac.at/Luftbildarchiv/intro/aa_aaint.htm)

Many archaeological sites have been severely damaged by land use – like plowing or urban development, or by natural processes like erosion.

An important goal of archaeology is to find sites over large areas quickly and cheaply so that they can be preserved rather than destroyed or exploited

Air surveys are an efficient way to accomplish this.

Partly true…but aerial archaeology is more useful than that…

5 sites identified in one aerial photograph around Hornsberg, Austria (University of Vienna photo)

Big picture can allow archaeologists to learn about the relationships between sites and between a site and its environment.Signs of roads and trails connecting sitesRemnants of old waterwaysVegetation relationships with sitesAssociations of sites with particular landforms,

etc. (e.g., sand dunes in Wyoming)

Other functions of aerial archaeology

Neolithic circular ditches in southern Austria(University of Vienna photo)

Linear roads radiating from Chaco site in NM contrast with modern roads that follow topography more (from a TIMS image)

Sites can be mapped effectively from the air to provide archaeologists with a guide for ground excavation

Applications, continued…

Roman villa (“lumps and bumps”) as seen at ground level in farmer’s field – difficult to tell something was there and farmer had no idea that it was an entire villa.

Image by Ashley Dace: Creative Commons

Same Roman villa as seen from the air – site discovered from air in 1979 associated with pot shards found in 1977. Original walls 60 cm below surface.

Plow disturbance of rock pile used for building

Site continues into another field but obscured by different vegetation

Map of the villa created from the air photo and ground survey

(http://www.villa-rustica.de/villa/indexe.html)

Partially restored villa

Aerial images also provide an archive of site characteristics that can be a valuable record of sites in their original conditionSite configurationSurrounding features (e.g., ancient roads, etc.)

Can serve as a permanent record of the undisturbed site

Archiving

Balloon flights in early 1900s1906 – Air photos of Stonehenge from military

balloon Cameras attached to kitesOpen seated biplanes in 1920s and 30s

O.G.S. Crawford in England active in this period and said to be the “father of aerial archaeology”

P.A. Poidebard active at same time in SyriaWorld War II pilots documented sites that they

noticedAerial archaeological survey became more

systematic in the 1960s

History of aerial photography for archaeology

1931 air photo of Braunsberg, Austria(University of Vienna photo)

Manned fixed winged aircraftManned helicoptersKitesBalloonsUltralight aircraftUnmanned aircraft

Platforms used for archaeolgical photos

Shadows of features (shadow marks)Differences in soil color (soil marks)Differences in height and color of crops (crop

marks)

Aerial view gives an archaeologist the perspective necessary to integrate clues over large areas to see pattern that might not be visible on the ground.

Photo features useful for identifying sites

Shadow marks in New Mexico

Shadow marks in Wyoming – rocks point to a pass(Photo ©Rita Donham)

Crop marks: Signs of old walls in Moravia(Photos from University of Vienna, Austria)

Soil marks in Austria(University of Vienna photo)

Site visibility affected by many factors:Soil typeVegetationClimateTime of day or year when photos takenSometimes only major features visible—or none

at all expressed clearly at surfaceSome sites hidden in caves, under cliff

overhangs, etc.

Challenges and problems with air photo interpretation for archaeology

New tools like Google Earth provide ability to do aerial archaeology of anywhere on earthSomewhat resolution-limited for non-populated

areasAbility to tilt for terrain visualization

Aerial Archaeology with Google Earth

Aerial photography is widely used for archaeological surveys, site mapping, site context and archiving

Discovery of sites relies on clues – differences in soils, vegetation, topography

Modern tools like Google Earth provide easy access to aerial archaeology

Identification of sites can help preserve them—especially important as human developments expand globally

Summary