For the Student
Useful Web Links
CHAPTER 2 : Discovery and Investigation
2.4. GEOGRAPHICAL INFORMATION SYSTEMS (GIS)
The expansion of large survey projects raised interesting problems about recording and classification which directed attention back to the question of defining a site. Few archaeologists would find any difficulty in recording artefacts or building materials found on the surface of the ground, or recognising and classifying physical features such as a stone wall or mound. But what combination of surface finds and surviving structures constitutes a site?
- The Discovery Programme 'The Discovery Programme is an archaeological research institution dedicated to investigating Irelands past from earliest times and presenting the results to as wide an audience as possible. Within this site you will find detailed information on the work of the Discovery Programmes projects, past, present and future, and the kinds of technology we use on a day-to-day basis.' This superb website has links to the methods of discovery as well as to the Programme itself.
- Heritage and Buildings English Heritage: Archaeology is the study of past societies and individuals through the physical remains they have left us. Architectural history is about understanding buildings and their surroundings in their wider cultural, historical and social context.'
- Survey and Recording Information about the work of the Royal Commission on the Ancient and Historical Monuments of Scotland: 'Our survey teams use photography, measured drawings and on-the-ground analysis to record the built environment of Scotland. The teams focus their efforts on three keys areas: field survey of archaeological sites and landscapes; aerial survey of all types of sites and buildings; and topographical areas.'
2.2. FIELD ARCHAEOLOGY
2.2.1. Field Survey
2.2.2. Fieldwalking (and shovel testing)
2.2.3. Recording and topographic/earthwork surveying
2.2.4. Historic landscape and monument inventories
2.2.5. Underwater survey
Discovery is pointless without recording, but observers (ancient or modern) only record what they see, and what they see is determined by what they consider to be significant. Bias is inescapable, but may be reduced by modern archaeologists if they explain their ideas and research strategies explicitly, rather than treating fieldwork as an objective recording exercise.
- Hand-held data collection and GPS logging A review of some equipment from Internet Archaeology, with a helpful glossary of terms (Nick Ryan, Jason Pascoe, David Morse: University of Kent at Canterbury)
- Achill Archaeological Summer School A training course in archaeological field methodology at a Deserted Village, Slievemore, Ireland
- Knowlton henge complex, Dorset Survey and excavation at a Neolithic henge complex by University of Bournemouth
- Surveying in Pompeii Example of the use of a Total Station by H. Eiteljorg II, with further explanatory links.
Much fieldwork now takes place in the context of field survey - a comprehensive study of an area selected either because it is threatened with damage by development or agriculture or because it has the potential to answer questions generated by wider archaeological research.
- Fields of North Mayo A neolithic landscape in Ireland
- Pylos Regional Archaeological Project Department of Classics, University of Cincinnati. Follow the links to interesting maps and studies of pottery (etc).
2.2.2. Fieldwalking and shovel testing
Fieldwalking is the simplest procedure employed in fieldwork, and it provides many opportunities for amateurs and beginners to get involved. Although it may include the recognition of sites through minor fluctuations in the form or character of the ground in areas that have had little investigation in the past, the main purpose of fieldwalking is normally the collecting of artefacts from the surface of ploughed fields.
- FIELDWALKING: information from the Sedgeford Historical and Archaeological Research Project- a long-term, multi-period, multi-disciplinary research project set up to investigate the entire range of human settlement and land-use in a typical north-west Norfolk parish, from the earliest times to the present day.'
- Locating sites surface survey and shovel testing: 'In grassy or wooded areas, sites can be found by digging small holes (roughly 50 cm diameter) at regular intervals (usually 10-15 meters apart). The soil is screened to look for artifacts. Each hole is mapped, and any artifacts are mapped by hole and bagged separately. Because this digging destroys a portion of the site, it should be supervised by trained archaeologists who have a good reason for investigating an area.' (Mississippi Valley Archaeology Center (MVAC))
2.2.3. Recording and topographic/earthwork surveying
Ground-level photography remains important for documenting sites, and can place them into a local context as well as including people engaged in fieldwork to illustrate methodology.
- Archaeoscope: digital elevation model of Cawood Castle Garth, N. Yorkshire - 'This image is derived from data collected using Leica GPS equipment recording readings at close intervals. ... This is perhaps easier to interpret when rendered and animated'
- Earthworks: 'A mass of 'humps and bumps' can seem to lack form and pattern, especially when they represent a number of different periods of activity, and are possibly not in a good state of preservation. However, by systematic measurement and recording, it is almost always possible to 'make sense' of these features. Accurate maps of earthworks can be used to reconstruct the plans of villages and field systems, and help archaeologists decide where to excavate for more information.'(Past Perfect: the virtual archaeology of Durham and Northumberland)
2.2.4. Historic landscape and monument inventories
Ideally, a database of sites, with plans, photographs and sources of further information, should serve a number of different purposes. These may include further research by individuals who were not involved in collecting the data, such as academic archaeologists or planning officers considering the impact of development proposals.
- The Archaeology Service for Aberdeenshire, Angus and Moray: 'The databases held in the office by the Service contain information on nearly 25,000 sites of archaeological and historical interest ranging from Mesolithic flints to airfields of World War II. The information consists of a computerised database linked to a GIS (Geographical Information System) with further physical records of maps, photographs, articles and reports. The databases are updated regularly with all new discoveries, including those made by our own aerial photography programme. They used as a resource for planning, forestry, roads, water services, oil & gas pipelines, electricity companies, tourism, as well as educational establishments, local societies and individuals.'
- Enhancing the record through remote sensing The application and integration of multi-sensor, non-invasive remote sensing techniques for the enhancement of the Sites and Monuments Record. Heslerton Parish Project, N. Yorkshire, England (Dominic Powlesland, James Lyall and Daniel Donoghue: Internet Archaeology)
- National Monuments Record A division of English Heritage with extensive pictorial archives (click on Online Resources)
- National Archaeological Database: 'NADB-MAPS (Multiple Attribute Presentation System) Library provides GIS layers related to archeological data. The GIS maps below show national distributions of cultural and environmental resources across the United States. For each entry you will be able to view/download a map, as well as metadata information.' (US National Park Service)
- Hampshire and Wight Trust for Maritime Archaeology 'After one and a half decades the Hampshire and Wight Trust for Maritime Archaeology is continuing to contribute to our understanding of the region�s cultural heritage. 2005/2006 has witnessed the discovery of new sites which range from submerged Stone Age settlements to shipwrecks lost within the last hundred years. As we learn more we have been keen to disseminate information widely and to this end we have invested time in exhibitions, displays and education.'
- Historic Environment Record (HER): The Archaeology Section maintains and enhance the HER. The HER is principal source of information about the Historic Environment of County Durham and Darlington. Local authorities, developers, consultants, academic researchers and members of the public all use the HER. It records all aspects of our surrounding environment that have been built, formed or influenced by human activity. However, much of the information on the archaeology of County Durham is available on our extensive 'Keys to the Past' website at: www.keystothepast.info.'
Fieldwork under water is not unlike that on land, for it relies both on broad-scanning methods for identifying wrecks or other underwater structures, and on detailed visual inspection of smaller areas or individual locations by divers.
- 2007 Aegean and Black Sea Expedition. 'The 2007 Aegean and Black Sea Expedition consists of three distinct projects � a geological study in the Sea of Crete, an archaeological survey and shipwreck excavation off the coast of Ukraine in the Black sea, and an archaeological investigation of a well-preserved shipwreck off Turkey in the Black Sea. In addition to the scientific objectives, this cruise will be used as an opportunity to test new technologies that will be utilized on board the new NOAA ship Okeanos Explorer.' (Institute for Archaeological Oceanography (IAO)Institute for Archaeological Oceanography, University of Rhode Island)
2.3. REMOTE SENSING
2.3.1. Airborne prospection
:: Multispectral and thermal prospecting
:: Interpretation of aerial images
2.3.2. Geophysical and geochemical surveying
:: Ground penetrating radar (GPR)
:: Seismic prospecting and geochemical examination of soil
:: Underwater location devices
2.3. REMOTE SENSING
Remote sensing devices do make contact with the ground, but are still 'remote' from the buried archaeological features that they are designed to detect.
- The Practice of Remote Sensing in Archaeology document describing and illustrating the principal methods of studying sites on the ground or from the air (The Center for Advanced Spatial Technologies, University of Arkansas)
Optical aerial photography has undoubtedly made the greatest single contribution to archaeological fieldwork and recording. Besides giving attractive bird's-eye views of surviving sites, aerial photography is overwhelmingly important in bringing to light buried sites visible through discolorations in the overlying soil or vegetation .
Aerial photography provides a useful supplement to observations made during fieldwork on visible sites with traces of earthworks or walls surviving above ground.
- Introduction to Aerial Archaeology '...aerial archaeology is more than just taking photographs, although this was and sometimes is still considered to be its main subject. In fact, it goes far beyond the mere acquisition of data, and you even don�t need photographs to perform aerial archaeology: you can use also satellite images, thermal images or airborne radar images. To perform aerial archaeology means above all, to make archaeological use of this kind of remotely sensed information.' (Aerial Archive, Institute for Prehistory and Protohistory of the University of Vienna)
- Aerial Archaeology Research Group (AARG) "...provides a forum for the exchange of ideas and information for all those actively involved in aerial photography, photo interpretation, field archaeology and landscape history. This also includes the use of aerial photography in defining preservation policies for archaeological sites and landscapes."
- Archiving Aerial Photography and Remote Sensing Data - A Guide to Good Practice (Arts and Humanities Data Service). See in particular Section 2 (Aerial Photography, Remote Sensing, and Archaeology): 'This section presents a brief overview of the history and role of aerial photography and remote sensing in archaeology. It discusses the principal methods employed and, briefly, the data formats output. The section ends with a 'suggested reading' list pointing the reader to key texts.'
- Cranborne Chase Bournemouth University: details of geophysical surveys and excavations, related to aerial and ground-level photographs of the sites
- THE PAST REVEALED 'In 1928, a pilot flying over Caistor noticed a regular grid pattern of pale parched corn in the green barley fields inside and around the Roman town.' The photograph is accompanied by photographs of the excavation of stone structures, and forms part of A virtual tour of Caistor Roman Town, Norfolk. (John Peterson, University of East Anglia, Norwich, UK)
- Baker Aerial Archaeology Introductory information and explanations, primarily from Southwestern U.S.A.
- Aerial-Cam Commercial company offering low-level aerial photography from a telescopic mast extending up to 22 metres -no aeroplane required! Beautiful sample photographs of sites and buildings on this site.
----- Multispectral and thermal prospecting
From the 1970s airborne prospecting has expanded to include devices that record a wider range of wavelengths, including multispectral imaging sensors, thermal imaging radiometers and imaging radar. All of these collect data in digital form that is eminently suitable for processing by computer to produce the best results.
- Classification of multispectral aster imagery in archaeological settlement survey in the Near East: PDF document by Bjoern H. Menze and Jason A. Ur: 'Overall we found that multi-spectral ASTER imagery can be used to provide highly specific information on character and composition of the ground, a tool which can be used in survey planning or the screening of wide regions for conservational issues or studies in landscape archaeology.'
This is a new technique for surveying surface remains from the air or from the ground. It can also be used to record standing buildings.
- Surveying Knowlton Church and Henge using 3D Laser Scanning: PDF document by By A. Carty (Archaeoptics Ltd) and Thomas A. Goskar (Wessex Archaeology)
- Heritage3D This project supplies information to professionals and students on all forms of 3D survey and recording and has case studies to view.
----- Photogrammetry
Conversion of optical photographic images into digital formats allows them to be used more easily with other data (for example from surveys and geophysical instruments) and incorporated into GIS.
- Photogrammetry and Archaeology: Aerial Archive, Institute for Prehistory and Protohistory of the University of Vienna
----- Interpretation of aerial images
It is not always easy to distinguish between archaeological features and natural geological phenomena; a thorough knowledge of archaeology is required for any attempt to classify and date sites according to their form.
- Air Photo Services Ltd Case Studies Index: 'A skilled aerial photographic interpreter can differentiate archaeological and natural features, and rectify the features to an Ordnance Survey map base. This interpretation and mapping is used directly by our clients as an accurate guide to locate trenches for evaluation and areas for further survey.'
2.3.2. Geophysical and geochemical surveying
The use of geophysical prospecting devices is an efficient method of exploring invisible aspects of the buried site and relating them to a measured survey. As with aerial photography, the main purpose of geophysical instruments is to distinguish anomalies, hopefully of human origin, from the natural subsoil.
- Geophysics clear introduction from Past Perfect (Durham and Northumberland County Councils)
- Archaeological Prospection Classified collection of links from Bradford University
- The WROXETER HINTERLAND Project: geophysical surveying (PDF doc) 'relies in large part on non-invasive surveying techniques for the mapping of archaeological features both inside Wroxeter itself and on sites in the Hinterland. Such techniques include aerial photography (AP), geophysical prospecting, and topographical surveying.'
- Knowlton henge complex Some very impressive results from the Neolithic henge complex of Knowlton, Dorset, by University of Bournemouth
- Cranborne Chase Bournemouth University: details of geophysical surveys and excavations, related to aerial and ground-level photographs of the sites
- List of Projects Interesting results from sites in Gloucestershire - project information from Dr Alistair Marshall
- Conservation Bulletin A lavishly illustrated magazine published by English Heritage containing examples of geophysical surveys.
When an electric current is passed through the ground between electrodes, the resistance to its flow may be measured. A current will pass relatively easily through damp soil, but drier compact material such as a buried wall or a cobbled road surface creates higher resistance.
- Resistivity explanation from Past Perfect
----- Magnetic surveying
Magnetometers detect deviations from the general background of the subsoil, indicated by variations in its magnetic field. Several aspects of past human occupation cause suitable anomalies.
- Magnetometry explanation from Past Perfect
- STANTON DREW STONE CIRCLES "...the [technique] that has so far proved most effective at Stanton Drew is magnetometry. This relies on the fact that all soil is slightly magnetic and that this magnetism is concentrated and enhanced in many types of archaeological feature." Paul Linford: Copyright Historic Buildings & Monuments Commission for England.
----- Metal Detectors
Metal detectors are not only popular with members the public who regard their use as an innocent hobby, but also with professional treasure-hunters who plunder sites for profit. Most types penetrate the soil only to a very limited extent, but they have been used by archaeologists to locate dispersed metal artefacts.
- Portable Antiquities Scheme: 'The Portable Antiquities Scheme is a voluntary scheme to record archaeological objects found by members of the public in England and Wales. Every year many thousands of objects are discovered, many of these by metal-detector users, but also by people whilst out walking, gardening or going about their daily work. Such discoveries offer an important source for understanding our past.'
----- Ground penetrating radar (GPR)
Electronic signals are transmitted into the soil, and bounce back to a receiver. The signals are altered by the density and position of whatever they encounter underground, and the patterns received from the ground are plotted diagrammatically.
- Ground-Penetrating Radar explanation from Past Perfect
- ZODIAC| GPR, Georadar & Geoelectrics ZODIAC is a 3D modeling and outputting service designed for scientific research pertaining to geophysical and archaeological prospection of processed ground penetrating radar tomographies (3D GPR, georadar time slices) and 3D geoelectric tomographies field measurements yielding uncompromising and non-speculative results.' Examples with vivid graphics from cdmb architects, Berlin)
----- Seismic prospecting and geochemical examination of soil
Acoustic or seismic investigation is very common in geological survey and, in the form of sonar, used under water for archaeological purposes, but it has not been utilised extensively for archaeology on land.
- Soil/Sediment Analysis PDF document about prospection techniques, including phosphate analysis: 'This document provides background information on the principal types of soil/sediment analysis undertaken by UWLAS and presents details of the analytical methods employed.' (University of Wales, Lampeter, Archaeological Services)
----- Underwater location devices
Sonar scanning works in the same way as radar, but sonic (rather than electronic) signals are transmitted and received. Side-scan sonar can cover large areas because the signals are transmitted sideways to detect irregularities on the surface of the seabed.
- Side Scan Sonar: clear explanation with illustrations from Nordic Underwater Archaeology pages
- Lake Ontario Maritime Cultural Landscape Project: includes a chart showing planned marine remote sensing survey lines spaced 15 meters apart (from online Museum of Underwater Archaeology)
2.4. GEOGRAPHICAL INFORMATION SYSTEMS (GIS)
Computers that combine large data-storage capacity with fast mathematical processors and high-quality graphic display were typified in the 1990s by Sun workstations, but by the twenty-first century such features had become readily available on desktop PCs. Likewise, GIS software became less complex and more user-friendly over the same period.
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GIS for Archaeology: 'Archaeologists,
as researchers and resource managers, understand the importance of
geography. Its variables exert a strong influence on human behavior
today, and archaeologists are aware of the significance of this
influence in the past. Geography also influences the degree of exposure
of archaeological sites, and the impacts that they face from human
activity and natural forces. GIS facilitates mapping to analyze
depositional patterns as well as catalog and quantify artifacts. It can
provide a well-structured descriptive and analytical tool for
identifying spatial patterns.'
Informative pages from Environmental Systems Research Institute, Inc. (ESRI) including PowerPoint presentation of the basics - Making the Most of Maps: Field Survey on the Island of Kythera (PDF file of article from Journal of GIS in Archaeology, Volume I).Excellent illustrations explaining use of GIS
- GIS Guide to Good Practice 'This document is designed specifically to provide guidance for individuals and organisations involved in the creation, maintenance, use and long-term preservation of GIS-based digital resources.' (Archaeology Data Service)
2.5. LANDSCAPE ARCHAEOLOGY
The term retrogressive analysis is sometimes employed to describe how landscape archaeologists work back from modern features to the fragmentary remains of earlier landscapes.
- Reading the land '50 years ago, most historians thought Britain�s landscape dated mainly from the 18th century. Then landscape archaeology began, and the rest is history, says Peter Fowler.' Article from British Archaeology (published by Council for British Archaeology).
- Historic Landscape Characterisation PDF file from English Heritage: 'England's rural landscape is one of the jewels of our national heritage. It is too easily overlooked when we concentrate on individual buildings or archaeological monuments, and its historic dimension can be too easily missed if landscape is admired as beautiful scenery. Through its programme of Historic Landscape Characterisation (HLC), run in partnership with County Council Sites and Monuments Records, English Heritage is a leader in this field.' For a full account, download Using Historic Landscape Characterisation [Pdf, 8mb].
- Devon County Council HLC: 'In order to record and understand the wider historic landscape of the county, Devon County Council and English Heritage have undertaken a Historic Landscape Characterisation project for the county... Historic Landscape Characterisation is a method for understanding and mapping the landscape that we see today with reference to its historical development. The Devon project has used digital mapping, which means that the results can be updated in the light of future research.' An interactive site that hears you to explore maps at different scales.