Abstract Architecture conservation deals with
heritage structures as well as heritage sites, where we learn about the
economic and social conditions of the past. In the present scenario, heritage
buildings are under threat from natural disaster, unpredictable weather,
pollution and other illegal activities. There
are many research projects happening in the field of geospatial technologies, which
could bring benefits to urban planners, architects, conservationist, managers
and other experts who deal in the process of heritage management and urban
regeneration. In this paper we will discuss various case studies
using geospatial tools like GIS, remote sensing, laser scanning, drone,
photogrammetry, etc. for architecture conservation and will do their critical
analysis which will provide
answers to a wide range of questions focusing on detail and spatial extent.
Policy-makers, urban planners,
architects and conservationist not only need answers to these questions
but also practice them in a reliable, transparent, spatially explicit and
inexpensive manner.

 

Keywords: critical analysis, remote sensing, geospatial
techniques.

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1.    
Introduction

       1.1 GIS

Geographic information system
(GIS), An architectural heritage carries heterogeneous, multi-layered
information which goes beyond physical characteristics. It requires an
integrated presentation of various types of information for understanding and
management prior to the decision-making process of conservation. This
requirement consists of representation and management processes.

 

 

1.2 REMOTE SENSING

Remote sensing is the science and
art of obtaining information about an object, area through the analysis of data
acquired by a device (satellite) that is not in contact with the object, area
or phenomenon under investigation.

 

 

2.     GIS and Remote Sensing in Landscape Archeology

 

According to Sarah
H. Parcak “Landscape archaeology refers to how modern archaeologists assess,
interpret, analyze, and experience ancient landscapes in their modern forms.” There
are invasive and noninvasive ways in which archaeologists obtain their data. It
should be realized that archaeologists never “analyze” ancient landscapes, just
as they never “excavate” ancient sites. This infers that sites and landscapes
exists the same way as we humans do, in the present.

Landscape
archaeology takes into account a broad range of aspects regarding diverse
types of past human interactions with the environment (e.g., habitus, symbolic
and cognitive landscapes, social organization, subsistence strategies,
overexploitation and depletion of resources), multidisciplinary approaches
(e.g., geoarchaeology and environmental change, climate, winds, sea level and
coastlines, macro and micro flora and fauna,  fluvial systems, other resources), data
collection techniques (e.g., extensive surveys, excavation, coring) and
analyses (e.g., settlement pattern studies, dendrochronology, pollen cores,
soil micromorphology, GIS, simulation modeling) (Renfrew and Bahn 2016). For
this , NASA has a specific Space Archaeology program to fund scientists
applying remote sensing datasets captured from the mid-troposphere to archaeological
sites and landscapes ,according to Oxford Handbooks online .

There are various
practical researches done in Landscape archaeology, that has been proved
beneficial in the Landscape archaeology programme, namely:

Ø
Looting Detection and Site Monitoring

Ø
Exploring natural and anthropogenic risk for
cultural heritage in Cyprus using remote sensing and GIS.

 

2.1  CASE STUDY 1 :Looting Detection and Site Monitoring  

 

Middle East and
North Africa, archaeological site looting has increased over the years. Looting
is recognized by high – resolution satellite image revealing a dark pit or
square surrounded by a donut – shaped embankment of earth which is sometimes confused
with the excavated sites, so to avoid this issue a good GIS using previous excavation
and survey data.

 

To determine the increase
in looting Sarah H. Parcak has used time series data of satellite images. Archaeologists
uses open source data like Google map or Bing  these data to create risk assessment maps for
sites to suggest which parts maybe affected by future development. This, in
turn, may affect long-term site preservation and protection plans.

 

            

Figure 2.1.1: In a
2009 satellite image (left) of el Hibeh, Egypt, few looting holes are visible. An
image made in 2012 (right) documents a dramatic increase in looting. (Satellite
image courtesy: Sarah Parcak).

 

 

Figure 2.1.2: Satellite
photos made in 2010 (left) and 2013 (right) reveal an upsurge in looting at the
ancient site of South Dashur in Egypt.

 

By processing
different spectral signatures within archaeological sites and mapping of
subsurface remains many archaeological sites are detected.

There are few
studies which deal with the application of a risk assessment model to
archaeological monuments. Canuti et al. (2000) addressed the issue of
geomorphologic hazard with regard to erosion, landslide and flood processes for
the historical sites in Italy while Indirli (2009) highlights the use of the
GIS database in order to record natural hazards and structural vulnerability
for historical centre’s. Additionally, Carlon et al. (2002) used both
anthropogenic and natural factors to create a risk assessment model concerning
archaeological monuments in Venice.

 

Figure 2.1.3: Sarah
processes satellite data to find manmade materials underground. This bright
pink area is the ancient city of Mendes in Egypt, long lost in the sands of
time.

 

CRITICAL ANALYSIS

The images obtained are usually days, weeks
even months old and are not real –time, so do not show ongoing events, this can
be solved using “DRONES”, which requires permission. Secondly since Google
earth is an open source, so these images are also available to the thieves.

Dr. Parcak is also training authorities to
thwart looters by involving community leaders in tourism activities connected
to the ancient sites. That model was developed by the Sustainable Preservation
Initiative in Peru, which also has a looting crisis.

 

2.2 CASE STUDY 2: Exploring
natural and anthropogenic risk for cultural heritage in Cyprus using remote
sensing and GIS

 

Here Diofantos Hadjimitsis, Athos Agapiou,
Dimitrios Alexakis & Apostolos Sarris aim to examine and evaluate the
overall risk of cultural heritage (CH) sites in Cyprus due to anthropogenic and
natural hazards.

The risk evaluation involves GIS and Remote Sensing
techniques to highlight the benefit of such tools for monitoring CH Sites and
their surroundings in a systematic way. The site is endangered by different
environmental and human hazards such as air pollution agents, sea erosion and
uncontrolled urban activities. The tools like GIS, drones, satellite
imagery, etc. used for the
management of the archaeological, environmental and spatial information should
be able to transform different types of data mainly maps  to
manageable form as well as to enhance the integration and assessment capabilities.

Figure 2.2.1:
The selected sites are being taken from different historical periods starting from the Bronze Age up to the
medieval

 

METHODS

According to Diofantos Hadjimitsis, Athos
Agapiou, Dimitrios Alexakis & Apostolos Sarris there are four main steps
applied in order to evaluate the hazard and classify the monuments according to
their vulnerability.

1.      Risk assessment

2.      Identification of the risk

3.      Profile hazards

4.      Risk analysis

 

1.     
Analysis

  
Seismic Risk of the CH Sites – It’s a complex tectonic regime with Cyprean
arc being an active plate boundary that accommodates the convergence between the
African plate to the south and the Anatolian plate to the north. The earthquake
magnitudes can reach M_7.0

It is possible to estimate Peak Ground Acceleration
(PGA) or any other parameter relevant to seismic engineering, which can be
extracted from algorithms,
which further helps to offer the alternative for a realistic estimation of the
seismic hazard in those areas for which scarce (or no) historical or instrumental
information is available and to perform the parametric analyses.

 

Figure 2.2.2 : Distribution of earthquakes in
Cyprus from the antiquity (2150 B.C.) until 1995.

Data Source: Geological Survey Department of
Cyprus 1995.

 

Figure 2.2.3 : Map showing the seismic hazard
for Cyprus. PGA values for the island of Cyprus (percentage of average gravity
of earth). Data source: Cyprus Geological Survey.

 

1.1.    Sea water erosion of the CH Sites

The CH sites located near coastline are
threatened by shoreline erosion, sea wave storms, sea level rise, tsunamis, and
salt-decay. For this purpose, buffer zones indicating the proximity of CH sites
to the coastline were drawn in GIS environment.

Figure 2.2.4
: Distance of Cultural Heritage Sites from the sea

 

1.2.    EROSION

Diofantos Hadjimitsis, Athos Agapiou, Dimitrios
Alexakis & Apostolos Sarris believes that there are two factors that are needed to be
considered: the geological regime and the inclination of the relief. Using a
20m pixel size Digital Elevation Model constructed in the GIS environment with
the use of air photos stereo pairs (data provided from the Department of Land
and Surveys, Cyprus), the slope map of the island of Cyprus was created in GIS
environment.

 

Figure 2.2.5:(a)
Slope map of Cyprus.

Figure 2.2.5 : (b) Unified geological map of
Cyprus.

 

1.3.    Urban Expansion

The rapid urban expansion all over the island
has been indicated from

Hadjimitsis et al. (2005, 2009) and Agapiou et
al. (2010). Using archive satellite

images (CORONA) and multispectral Landsat and
QuickBird images Diofantos Hadjimitsis, Athos Agapiou, Dimitrios Alexakis &
Apostolos Sarris found that
 there is remarkable land use change. Moreover, by applying the
change detection techniques in ERDAS Imagine, it was proved that, a 20%
differentiation in the land use has occurred in the surroundings of the
archaeological site of Paphos. The CORINE Land Cover (CLC) database was used to
map different human activity areas. The CLC data set provides a high-resolution
description of land use patterns, making use of 44 different land cover classes
(Janssen et al. 2008). All the villages and cities were mapped in GIS environment
and a buffer zone of 1500m was created around the towns” as
stated by Diofantos
Hadjimitsis , Athos Agapiou , Dimitrios Alexakis & Apostolos Sarris.

 

Figure 2.2.6 : (a) Amathous archaeological site
in 1963 CORONA image and 2010 Google Earth.(b) Amathous archaeological site in
2010 Google Earth image. (c) Palaepaphos archaeological site in 1963 CORONA
image. (d) Palaepaphos archaeological site in 2004 QuickBird image.

(Image # Digital Globe, # 2011 Europa
Technologies, # 2011 Google Earth).

 

 

1.4.    Proximity of CH sites to the roads

Air pollution is a great problem, slowly deteriorating the
building elements of the monuments. Also the accessibility of an archaeological area by the
existing road network could have a positive or negative  consequence to the preservation of CH sites
as it could promote tourism which will help in flow of funds would be a positive
impact but if it would lead to urban expansion that would be negative.
Researchers created the major
road network of Cyprus in digital format in GIS environment through the digitisation
of topographic maps and then buffer zones of 500m and 1000m were created around the road network, in
order to examine the proximity of CH sites to the network. Diofantos
Hadjimitsis, Athos Agapiou, Dimitrios Alexakis & Apostolos Sarris
classified road network into
four categories according to its traffic vibration as follows: highway network,
main road network, secondary road network and rural road network.

 

 

Figure 2.2.7: (a)Towns and villages of Cyprus.
(b) Proximity of CH sites to urban centres. (c) Comparisons of urban areas for
2000 and 2009. (d) Spatial expansion of urban areas during the last decade.

 

Figure 2.2.8 ;(a) Major road network of Cyprus.
(b, c) Proximity of CH sites to road network , (d) Classification of road
network.

 

In order to analyse air pollution impact to the
archaeological sites of Cyprus,

atmospheric path radiance (Lp) and aerosol
optical thickness (AOT) was determined for the cloud-free Landsat image
acquired on 23 August 2009 .

Path radiance is an indicator of air pollution
in the area. The determination ofatmospheric path radiance (and AOT) was
carried out using “the
darkest pixel

atmospheric correction method” that has been found to be an
effective method using grid cells where Lp for each grid was calculated for the visible
bands as shown by Hadjimitsis and Clayton (2009).

 

Figure 2.2.9
:Division of Landsat TM in grid cells

 

3. OVERALL RISK
ASSESSMENT

 

The risk index was specified by the authors
according to certain methodology:

For each participating parameter, a value of
zero was assigned in GIS environment to areas of low risk zones, a value of one
was assigned to areas of moderate risk zones and finally a value of two was
assigned to high risk areas.

Highlighted the urgent need for the construction
of new local plans and an update of planning legislation in order to achieve
the future goal of sustainable management of cultural heritage monuments. This
task will include the control of urban expansion in the vicinity of the
archaeological sites (including the control of air pollution and road network)
and, of course, the designation of sophisticated plans for protecting the sites
from any possible erosion and seismic events. Concerning estimation of losses
from a possible destruction of standing architecture these are mainly dependent
from the cover area of the site and mainly from its cultural asset either for
the whole humanity or for the local society. Moreover, this study provides the
authorities with the basic knowledge that can help them to specify the actions
they need to take for the protection of national heritage from natural
phenomena and anthropogenic impacts.

 

CONCLUSION

 

From the above
case studies we concluded that there is a lot a research going on in the field
of digital technologies concerning geomatics field and its integration with
architectural conservation for large regions but there is a lot to be done and
explored in this area. The role of administration plays an important part and
it needs to be more flexible and secured for the researchers to attain the
maximum potential. 

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