Crutchley, S. 2009. Ancient and modern: Combining different remote sensing techniques to interpret historic landscapes. Journal of Cultural Heritage, 10-1: 65-71.

Doneus, M., Briese, C., Fera, M. and Janner, M. 2008. Archaeological prospection of forested areas using full-waveform airborne laser scanning. Journal of Archaeological Science, 35-4: 882-893.

Opitz, R. and Cowley, D. 2013. Interpreting Archaeological Topography: Lasers, 3D Data, Observation, Visualisation and Applications. Oxford, Oxbow.

Pires, H., Gonçalves-Seco, L., Fonte, J., Parcero-Oubiña, C. and Fábrega-Álvarez, P. 2014. Morphological Residuals Model – a mesh decimation filtering tool for detection and contrast of archaeological evidences in point-cloud derived models, Journal of Cultural Heritage (forthcoming).

Bibliography

You can download this poster here Please, use the URL for citations http://hdl.handle.net/10261/101376

Conclusions

The use of interdisciplinary perspectives in which different methods are combined allow to improve the analysis, representation and interpretation of cultural heritage.

These techniques can speed up the work, retrieve the geometry of many of the sites destroyed or difficult to access and to facilitate the documentation and on-site registration, and also to generate topographical information that allows proper representation and to perform more detailed analysis.

Benefits of LiDAR

?Open access: LiDAR data in Spain is free and open access, freely distributed by the Spanish National Geographic Institute (IGN).

?Open source: one can generate such models using free (FrugoViewer, LAStools) and open source software (Quantum GIS, SAGA GIS).

?Low cost: with open access data and free/open source software one can generate good representations and very comprehensive analysis.

?High resolution data that covers large areas, allowing to map cultural heritage at different scales.

Benefits of Photogrammetry

?One can retrive geometric information from archival photos.

?It allows to recover missing landscapes and structures.

?Low cost: one can create geometry from multiple aerial photos, with software becoming cheaper, even free;

?Affordable technique in areas with no LiDAR data.

?It can be easely combined with other techniques like LiDAR.

Results

Application of airborne LiDAR to Baixo Minho bastioned fortifications

Visualization of the Amorín (Tomiño) and São Luís Gonzaga (Valença do Minho) forts

Visualization of the Atalaia de San Pablo de Porto (Salvaterra do Miño) and overlay of its plane (Jaime Garrido, 1982)

Google Earth 2003Vuelo Americano 1957

Visualization, analysis and reconstruction of Forte de Medos (Tomiño) from different data

Look at Sketchfab: https://skfb.ly/yUWD

Jaime Garrido Plant (1982)

LiDAR pointcloud

3D Model in GIS: visualization and analisys with MRM technique (Pires et al. 2014)

3D model from LiDAR data online

Aerial Photo and analysis of elements

3D reconstruction of the main elements

Sketch of the plant in Google earth

Based on 2 historical aerialphotos (1956)

Photogrammetric process with Agisoft PhotoScan

3D MODELSthat recover lost information (A Pereira´s fort now destroyed) and represent the landscape

Identification of homologous points in both photos Point cloud and aligned photos Dense point cloud

Photogrammetry

Reconstruction of the Extremo fortifications from historical photography (1956) with elements that do not currently exist (destroyed)

Aerial Photo overlay with Amorín’s historic plane

Aerial Photo overlay with São Luís Gonzaga’splane of Jaime Garrido (1982)

Bragandelo´s and A Pereira´s forts (Extremo, Arcos de Valdevez, Portugal)

Study Approach

Problems to identify the fortifications Visualization techniques used

LiDAR

Photogrammetry

In areas which are usually densely forested, the identification of archaeological features is still very problematic (Doneus et al. 2008). The introduction of Airborne Laser Scanning (ALS) or Light Detection and Ranging (LiDAR) helped to overcome this problembecause of its unique capability to penetrate vegetation canopies, allowing the documentation of the underneath topographic surface and thus the identification of cultural remains (Opitz and Cowley 2013).

However, in order to get an improved understanding of the landscape, we have combined airborne LiDAR data with historical aerial photos, which proved to be a valuable tool because each technique revealed different features, allowing the maximization of results (Crutchley 2009).

From aerial photos, we have used photogrammetry to build three-dimensional geometric information with which we have been able to generate new cartography, analyze it in GIS, compare it with other geometric representations, create 3D models, etc.

One of the key issues when we work with this type of architecture and its relationship with the landscape is to obtain a correct geolocation and capture its geometry.

In the case of Baixo Miño / Vale do Minho, several aspects have affected the fortifications identification and visibility:

?Fortifications built with earth, sometimes seems natural hills.

?Fortifications are complex structures that involve a succession of different geometric forms which materialize the maxims of bastion fortification, including the subordinate defense.

?Poor state of preservation due to:

?problems caused by the construction materials used (earth);

?many of them were intentionally destroyed at the end of the Guerra da Restauração Portuguesa (1640-1668);

?contemporary uses of land that have partially or totally altered the constructions.

?Its geometry and big size impede, in many cases, to capture in situ an overall picture of them, unless from elevated positions.

?Many of these architectures have been hidden by the vegetation, which means they can not be displayed either from elevated positions.

From the architecture to the lanscapeAnalysis of archaeological and patrimonial entities

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Micro-levelAnalysis of Nsa. Sra. da Concepción (Goián)

Map of impact

Plant of the fortification(Jaime Garrido 1982)

Viewshed in a range of 2 Km

Intensive survey

Semimicro-levelAnalysis of Goián-Vilanova de Cerveira-Medos Subsystem

Survey strategies

Relations betweenfortifications

Visibilities in a range of 2 Kmand fortifications relationship

with transit routes

Definition of the subsystem, of the fortifications that integrate it and of their control area

Intensive-selective survey

Macro-levelAnalysis of Baixo Miño / Vale do Minho Fortified System

Articulation of Baixo Miño / Vale do Minho landscape in defensive sets or Fortified Subsystems

Extensive survey strategy

Map with the relationship between visibility of the fortifications and fire beacons and the roads

Roads Zones with dense vegetation

Preserved areas

Urbanized respecting the previous form

Destroyed areas

Zones with vegetation

Areas with growing grapevine

Forte das Chagas

Torre dos Correa

Forte de San Lorenzo

Nsa. Sra. da Concepción

Torre dos Ratos

Intensive survey

The project: Modern Age Fortified Landscape in GaliciaWith the development of the Rebeca Blanco-Rotea PhD Architecture and landscape. Border fortifications in Southern Galicia and Northern Portugal, we have continued to investigate the relationship between the fortified architecture of this period and the construction of a cultural landscape that today has become an heritage benchmark of different areas of Galicia.

Many fortifications built in this period had a number of specific characteristics that obstructed their visibility directly in the field, which led to establishing a collaboration between disciplines like Archaeology of Architecture and Geospatial Technologies, so that we could explore different tools to enable us to locate these fortifications in this area, make them visible and acquire its geometry.

Modern Age Fortified Landscapes is a transversal and self-sustained project from Incipit, CSIC. It has been incorporated information from different archaeological projects. It focuses on the study and interpretation of Modern Age Galician fortified landscapes and is conceived from the Built Heritage Management, combining various links in the Cultural Heritage Value Chain. This is an interpretative chain establishes a series of successive instances from the identification of cultural heritage heritage until its receipt by the society.

One of the projects-base it was Fortrans, Plan Director de las Fortalezas Transfronterizas del tramo bajo del río Miño (2003), sponsored by the Dirección Xeral de Patrimonio Cultural of the Xunta de Galicia and directed by the architects Antonio Hoyuela, Fernando Cobos and Jaime Garrido, in which our team participated developing the archaeological work.

Studies areas in Modern Age Fortified Landscapes Project, wtih the diferents fortifications identify

Using airborne laser scanning and historical aerial photos to identify Modern Age fortifications in the Minho valley, Northwest Iberia

Rebeca Blanco-Rotea (LPPP, USC), João Fonte (Incipit, CSIC), Alejandro Güimil Fariña ( ), Patricia Mañana-Borrazás (Incipit, CSIC) LPPP, USCrebeca.blanco.rotea@usc.es joao.fonte@incipit.csic.es patricia.manana-borrazas@incipit.csic.esalejandro.guimil.farina@gmail.com