When I was asked to give a presentation about non-invasive methods as potential tools for preventive archaeology, I thought that I might not be the right one to talk about this topic as I am neither working for Archaeological Cultural Heritage Management nor am I a technical expert for the various archaeological surveying techniques. On the other hand I am intensely dealing with non-invasive techniques, – mainly remote sensing methods – as the manager of the European networking project ArchaeoLandscapes Europe (ArcLand) which brings together experts and expertise in these fields from all over Europe, to foster the use of these techniques and methods for research as well as for site management, site monitoring, site protection and site presentation. My colleague Martin Posselt is an expert in geophysical surveying and he will focus on this to show you the advantages as well as some pitfalls of geophysics as tools for preventive archaeology. The use of the different tools for remote sensing is not established in all countries of Europe to the same extent. So as Martin is focusing on geophysics with some case studies a bit later, I will start with a brief overview of existing archaeological surveying methods, highlighting the pros and cons of their use for preventive archaeology. - -
From my current project work I am well aware that the use and the acceptance of some non-invasive methods are not equally distributed all over Europe so please allow me to start with a short introduction of methods & techniques. Martin will continue describing potential advantages and pitfalls for the use of geophysical surveying techniques by presenting some case studies. - -
Archaeology is of course dealing with pyramids, temples, large visible mounds and so on. But archaeology also is dealing with invisible things, things that are hidden beneath the soil. - -
And those are the features we mainly have to deal with, and that cause the biggest problems when talking about preventive archaeology – so how can we protect things that are not visible? - -
That leads us to the use of non-invasive techniques. you can only deal with things you know and don ’ t destroy it just to find out how it looks like before you can either protect it or excavate and document it - -
Archaeological features show up on aerial pictures in a number of different ways, depending on soil texture, soil humidity, temperature, lighting and so on. This is the basis of course for the pros and cons of this technique I t is dependent on weather, climate, etc. so cannot be used at all times not all features show on aerial pictures (at all times) the resulting information is relatively coarse as regards the details of the documented sites But on the other hand aerial archaeology is very time effective, it can give a first glimpse of what is there and it can cover very large areas in a short time - -
One of the newer surveying techniques for archaeology is LiDAR, also know as Airborne Laser Scanning. LiDAR is measured from the air with radar like laser scans. With the help of a GPS device the coordinates of each measured point on the ground can be calculated with very high precision. It only works with 3dimensional features but it allows for semi-automatic analyses, highlighting potentially interesting features. One other big advantage is the possibility to not only measure the surface of the ground in open areas but also in terrain that is covered by bushes or trees. Special filtering algorithms allow to digitally remove these features so that for example prehistoric grave mounds or other structures like even ridge and furrow remains can be discovered by their height differences in the woods as you can see on the following pictures. - -
The picture here shows the LiDAR scan of a Celtic hillfort in the Czech Republic, densly covered with trees and bushes which you can see here as the darker areas. - -
After a bit of advanced filtering the vegetation has been removed and the image impressively shows the ditch and rampart system of the hillfort as well as a number of other features. - -
Another example shows a burial mound in the forest near a Celtic hillfort in Germany, which became visible after digitally removing the forest canopy. - -
Geophysical surveying methods comprise a variety of different techniques: Magnetometer survey Earth resistance survey (geoelectric survey) Ground-penetrating radar (GPR) They all are: non-destructive machine-based in most cases less expensive than excavations can cover very large areas But their disadvantage is the expert knowledge one has to have in many cases to be able to handle the data derived from various measurements and the dependency of features and surrounding soil I am not going into any details here as this is the topic of Martin ’ s part of the presentation - -
We have been talking about the disadvantages of various non-invasive methods but let usnow focus on their advantages: non-destructive amend each other very precise nearly complete cover large areas fast much lower costs than caused by excavations - -
Let us conclude: One can only protect, monitor and manage what s/he knows – > Large scale surveys are not only a technique for archaeological research but also for Cultural Heritage Management Site protection is an expensive as well as a time consuming task – > Modern geophysical and remote sensing methods are a possible solution Surveying data is the ideal basis for decision making in urban land-use planning, to assess the threads from erosion, looting and plundering or from ploughing and to monitor archaeological sites During building and construction planning the areas of archaeological interest can be taken into account – > not only Archaeology or Cultural Heritage Management benefit from large scale surveys but also investors and stakeholders - -
Non-invasive Techniques – Tools for Preventive Archaeology?
Non-invasive TechniquesTools for Preventive Archaeology?Axel G. PosluschnyRoman-Germanic Commission ofthe German ArchaeologicalInstituteposluschny@rgk.dainst.deMartin PosseltPosselt & Zickgraf -Archäologisch-geophysikalischeProspektionen GbRposselt@pzp.deArcLand PZP GbRwww.archaeolandscapes.eu www.pzp.de
Content• Introduction of methods & techniques• Aerial Archaeology• LiDAR/ALS• Geophysical surveying• Case studies – advantages and pitfalls• ResumeRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
Roman-Germanic Commission/DAIhttp://www.ohiotraveler.com/images/serpent%20mound.jpghttp://www.ohiotraveler.com/images/serpent%20mound.jpghttp://www.online-reisefuehrer.com/bilder-reisen/tuerkei/ephesos.jpghttp://www.online-reisefuehrer.com/bilder-reisen/tuerkei/ephesos.jpghttp://www.zum.de/Faecher/G/BW/Landeskunde/w3/provence/vienne/http://www.zum.de/Faecher/G/BW/Landeskunde/w3/provence/vienne/augustus1.jpgaugustus1.jpghttp://www.aegypten-spezialist.de/uploads/pics/gizeh-cheops-sphinx.jpghttp://www.aegypten-spezialist.de/uploads/pics/gizeh-cheops-sphinx.jpgVisible features in Cultural Heritage Managementwww.archaeolandscapes.eu www.pzp.de
Roman-Germanic Commission/DAIBraasch/Christlein1982Invisible Features in Cultural HeritageManagementwww.archaeolandscapes.eu www.pzp.de
Aerial ArchaeologyRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de• dependent on weather,climate, etc. so cannot beused at all times• not all features show onaerial pictures (at all times)• relatively coarse as regardsthe details of thedocumented sites• very time effective• can give a first glimpse ofwhat is there• can cover very large areas ina short time
LiDAR/ALSRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.deLiDAR (Light Detection AndRanging) – ALS (AirborneLaser Scanning)• only shows3dimensional features• semi automaticanalyses are possible(highlighting potentiallyinteresting features)• works in forested areas• covers large areas
LiDAR/ALSCeltic hillfort Vlada in Bohemia – with forest canopyřRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
LiDAR/ALSCeltic hillfort Vlada in Bohemia – without forestřcanopyRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
LiDAR/ALSDetecting so far unknown grave mounds in the forestnear a Celtic hillfort in GermanyRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
Geophysical Surveys• Geophysical surveying methods comprise a variety of differenttechniques:• Magnetometer survey• Earth resistance survey (geoelectric survey)• Ground-penetrating radar (GPR)• They are:• non-destructive• machine-based• in most cases less expensive than excavations• can cover very large areas• their disadvantage is the expert knowledge one has to have inmany cases to be able to handle the data derived from variousmeasurements and the interdependency of features andsurrounding soilRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.deFriedberg-Bruchenbrücken, Germany. Magnetogram pasted to a cadastremap.1 Detail with groundplan of house 10.2. Excavation of 1984-85.
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.deTypology of groundplans of early neolithic houses.To the left: earliest type, to the right developed type(Lüning u. Stehli).
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.de(W. Reinhard, Die keltische Fürstin von Reinheim)
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.deArea of magnetometersurveyOutline of the plannedby-pass-roadMotorway A5Bad Homburg-Ober-Eschbach/Ober-Erlenbach (Hochtaunuskreis) 2001.Geophysics and Magnetic ghosts.
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.deMagnetogramBad Homburg-Ober-Eschbach/Ober-Erlenbach (Hochtaunuskreis)2001, Posselt & Zickgraf (PZP)Fluxgate-Magnetometer (Ferex)dynamics +/- 3 nT (white/black)Details with groundplans of houses
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.deBad Homburg-Ober-Eschbach/Ober-Erlenbach 2001.Fluxgate-Magnetometer (Ferex) dynamics +/- 3 nT(white/black)Magnetogram and interpretive drawing of LBK-houses 1 and 2
Posselt & Zickgraf Prospektionen GbRwww.archaeolandscapes.eu www.pzp.deBad Homburg-Ober-Eschbach/Ober-Erlenbach 2001.Section of circular ditch with invisible feature.
• The large variety of modern surveying methodshave a number of great advantages:• non-destructive• amend each other• very precise• nearly complete• cover large areas• fast• much lower costs than caused by excavationsResumeRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
• One can only protect, monitor and manage what s/he knows–> Large scale surveys are not only a technique for archaeologicalresearch but also for Cultural Heritage Management• Site protection is an expensive as well as a time consuming task–> Modern geophysical and remote sensing methods are apossible solution• Surveying data is the ideal basis for decision making in urbanland-use planning, to assess the threads from erosion, lootingand plundering or from ploughing and to monitor archaeologicalsites• During building and construction planning the areas ofarchaeological interest can be taken into account–> not only Archaeology or Cultural Heritage Management benefitfrom large scale surveys but also investors and stakeholdersResumeRoman-Germanic Commission/DAIwww.archaeolandscapes.eu www.pzp.de
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