Remote sensing should be used more in the Algarve to prevent heritage destruction

The heritage and archaeological characterization of Ilhéu do Rosário, at the confluence of the Odelouca river with the Arade river, in the municipality of Lagoa, is just one of the most recent works by the specialist company ERA Arqueologia in the area of ​​remote sensing.

This project, which will be presented on the 30th, in Lagoa, was one of the interventions addressed in the workshop «Remote Sensing in Rural Areas», promoted by the company in Loulé, within the scope of the Odissey project – Remote Prospecting of the Past, which ERA Archaeology led, with two universities – Aveiro and Maia.

Nesse workshop, which was aimed at professionals, from archaeologists to municipal technicians or land managers, aimed to raise awareness among all participants about the potential of applying remote sensing methods in the context of heritage and land management.

According to the company, it was “a motivating action to raise awareness and debate with archaeology professionals from the Algarve about the potential of applying the most advanced techniques for detecting, characterizing and delimiting sites to archaeological heritage, without resorting to intrusive actions”.

Miguel Lago, administrator of ERA Archaeology, explained to Sul Informação what are the objectives of the initiative.

«Our idea is to overcome some deficiencies that exist in the Portuguese heritage, but not only, also in territorial management and planning», since this was «a workshop on identification and remote detection of heritage, that is, without intrusive methods, but from a perspective of managing heritage assets and also managing the territory”, he began by saying.

The idea is that “professionals, both in the field of archaeology, as well as technicians from regional administration, municipalities, and companies that have a major impact on the territory, are made aware of the new possibilities of characterizing and, above all, delimiting archaeological sites without intrusive actions and at much lower costs,” he added.

In the opinion of the archaeologist and administrator of the company specializing in services in this area, “one of the major problems in Portuguese archaeology is precisely the delimitation of sites”, “whether at the level of PDMs, or at the level of environmental impact studies and the application of their minimization measures in approved projects, or even at the level of urban and rural licensing, related to the construction of roads, motorways, photovoltaic plants, wind farms, in short, all types of projects that interfere in the territory”.

For investors or project promoters, Miguel Lago highlighted, “one of the dramas that always exists is, after all, where are the archaeological sites and what is their size?”

Now, “through this type of technique that we have been using recurrently and increasingly in recent years, it is possible to achieve many of these objectives, through very modern technology, which complements the traditional way of the archaeologist working, which is to travel the territory, look at the ground, look at the landscape, collect what is possible in terms of shards and observation of certain structures that emerge on the surface”.

All this using technologies such as LiDAR, which allows us to “observe what is hidden by bushes or forests, to observe hidden realities that archaeologists often cannot even access”, or “through methods such as geophysics, which allows us to observe what is completely buried”.

«It is through the combination of these various techniques that we are now able to obtain a set of very valuable data, which allows us, before even digging an archaeological excavation hole, to provide decision-makers, investors, property owners, construction producers and local authorities with very important information to help them plan their current lives».

The question that often arises, Miguel Lago points out, is to know “which projects should go ahead, where should they go, how will they affect heritage?”

“The planet is full of heritage. It is obvious that we cannot preserve all of it,” he stressed. But “the more we are able to understand it, the better we will be able to make decisions about what we can preserve and what we can give up, and under what conditions we can give it up.”

ERA Archaeology, thanks to the investments it has been making in recent years, in equipment, but also in people who know how to use them and take advantage of the data they produce, now has a “very strong installed capacity”.

O workshop which took place in the Activity Room of the Islamic Baths and Manor House of Barreto, in Loulé, also allowed the presentation of the Odyssey-
This is a project that was approved within the scope of Portugal 2020, “financially heavy”, as it involved an investment of 1,3 million euros, “with a very strong contribution from the European Union”.

It was based on a consortium led by ERA, which had “the basic idea, which was precisely to try to find mechanisms that would allow the automation of remote sensing work. In other words, it is one thing for us to have all this information. It is another thing to be able to automate human work based on aerial information. It is one thing to have maps and to search on maps, or in aerial photographs, or in LiDAR for anything that seems to us to be an archaeological site. It is another thing to teach machines to do this work for us and for us to simply go and confirm it”, from the perspective of “machine learning algorithm », explained Miguel Lago.

To verify whether this dimension was possible machine learning algorithm , "this involved scientific research, and we had to look for partners. We identified two academic partners: at the University of Aveiro, specialists in Artificial Intelligence, and at the University of Maia, specialists in image data processing."

According to the administrator of ERA Archaeology, “it was this synthesis between archaeologists, heritage technicians and specialists in engineering areas that made it possible to prepare the project, which was approved, received funding, and allowed us to achieve most of our objectives”.

And will the Odyssey project stay here?, I wanted to know. Sul Informação.

“In research of this kind, when it comes to an end, we can see that there is much more research to be done. That is why we are already planning a new application to continue the research with the same consortium, because all the members are interested in continuing the research, especially because there is still a lot of work to be done so that this can be widely applied”, replied Miguel Lago.

The company ERA Archaeology already has extensive experience in working with remote sensing technology, from North to South of the country, and even in France and Spain, as was shown in workshop in Loulé. Thus, João Fonte spoke about «Aerial LiDAR applied to heritage research and management», Tiago do Pereiro addressed the topic of «Geophysical prospecting for mapping buried archaeological anomalies», Bruno Gambinhas dealt with «Aerial Archaeology in Portugal: evolution and impact of aerial imaging in archaeological research» and José Carvalho spoke about «the practical application of remote sensing in the processes of valorization of archaeological sites», presenting some case studies.

These technologies, they explained, “do not replace archaeological excavation, they are always complementary.”

One region where these methods have been widely used, particularly in agricultural projects, is the Alentejo. Miguel Lago explained that his company has been working extensively in the Alentejo region, “in terms of geophysics, for several years now, particularly in the delimitation of archaeological sites”.

The archaeologist gave the example of “a farm that is going to undergo redevelopment, where it will be transformed from a traditional olive grove to a modern olive grove. Sometimes it involves dozens, hundreds of hectares.”

Now, there it is necessary to do “all the prospecting work, which traditionally was based on observing the terrain, seeing the fragments that existed on the surface”.

However, "from the moment we identify a reality that justifies geophysics, geophysics will allow us, for example, to map the plan of a villa Roman, quite rigorously. And we can tell the developer, the official heritage entities that will evaluate projects, where is, for example, the limit of this villa "Roman". All this saves the developer time and even money, but at the same time allows the project to move forward. "We are providing data that allows us to protect the archaeological site and develop the agricultural project in areas where this is possible".

The person responsible for ERA Archaeology highlights that, despite current good practices, initially «there was major destruction in the Alentejo, within the scope of the implementation of agricultural projects associated with the Alqueva system. And for several years, gross errors were made».

But, largely due to the influence of the then Regional Directorate of Culture of Alentejo, “there was the ability to significantly reverse this trend and, today, I think that quite meritorious work is being done in Alentejo”.

Large agricultural clients are “our biggest geophysics clients”. Often, with the data provided by this specialized equipment, it is not even necessary to carry out archaeological excavations, because the areas where possible structures are detected are left untouched, as a “reserve”.

“This type of client has no interest in archaeology, they simply want to know what is there on the ground, so as not to have any problems,” he added.

In Alentejo, Miguel Lago highlighted, “the archaeological approach to agricultural projects is very different compared to what happens in the Algarve, where we have little experience in this area, I don’t know if there is even anyone who has experience in this area”.

“There are agricultural projects with some relevance and probably with an impact on archaeological heritage in the Algarve that are not being carefully assessed and minimised in terms of impact”, as they should be, he stressed.

ERA Archaeology has already carried out a lot of work in the Algarve region, in this field of application of remote sensing technology: “we have already carried out some projects, namely in photovoltaic power plants, within the scope of environmental impact assessment processes”.

The truth is that, in this expert's opinion, "probably due to differences in regional approach, agricultural projects in the Algarve are being less careful, as they are being approved without being properly assessed from the point of view of interference with archaeological heritage."

In the Algarve region, geophysics is also being used by ERA Archaeology “in urban projects”. Miguel Lago recalled a project in the historic center of Faro, «in a sensitive area, in a very large development, with a very large area in terms of size, in which, before the architectural project was drawn up, a geophysical survey was carried out».

This allowed us to “get an idea of ​​what could exist there, namely Roman heritage” and thus it was possible to “direct the archaeological surveys that were required by the authorities to the right places, that is, we went straight to the sensitive points”.

«The geophysics tool is used as a preliminary approach, as a kind of x-ray that is taken before performing any type of operation on a patient, through which we have the ability to collect data, support the options for intrusive diagnostic approaches and greatly complement the information».

“This means that, for example, an urban planning department will have a much more acute capacity to analyze the heritage-friendly nature of an architectural or engineering project. And heritage entities will also have the capacity to make much more consistent licensing decisions,” he argued.

With this type of approach, “it is possible, in certain situations, that the developer himself, instead of excavating in a certain area that is very sensitive archaeologically, can opt for other interventions and, for example, create a garden in a very sensitive area archaeologically and build a building in a less sensitive area. Or, if he really has to build in that sensitive area, he already knows what he is going to do. There are no surprises.”