Monitoring Methods for the Mitigation of NaturalHazards' Impact on Tourist Cultural Sites

Land Information Science

Monitoring Methods for the Mitigation of Natural Hazards' Impact on Tourist Cultural Sites Christiana Mitsakaki and Amanda Laoupi ABSTRACT: This paper deals with a tentative proposal for the development of a monitoring framework in order to evaluate the vulnerability of a cultural site with respect to various types of hazards. The ultimate purpose of the research is to protect and conserve cultural heritage. In our paper, we investigate procedures for monitoring the long-term behavior of a cultural landscape in order to determine the most appropriate one to deal with such probable natural hazards as seismic events, volcanic eruptions, soil liquefaction, landslides, tsunami, and flooding.

Introduction he Nations' Universal tionUnited of Human Rights states, inDeclaraArticle 27, that "the right to a cultural heritage is an integral element of humanity." In many cases, once lost, cultural heritage cannot be restored or recovered, but we can prevent further losses. Disasters take a heavy toll not only in terms of human lives and economies but also the environment, society, and culture, all over the world.

Usually, countries take action after damage has occurred. But rather than financing relief, it is essential to think of hazard risk management as a coherent set of actions comprised of cultural hazard assessment and proactive planning, monitoring, risk prevention, intervention, and sustainable reconstruction. Although not all disasters can be avoided, preventive measures play an important role in mitigating their effects in a cost effective manner. In order to increase our capacity to handle disastrous events and decrease vulnerability of our cultural heritage to hazards, policies at all levels of government are needed that support and encourage integrated vulnerability assessment. The availability of a robust hazard assessment and monitoring system would then help nations absorb natural or human-triggered shocks.

While there are many methods of evaluating, classifying, and analysing hazards, an archaeologist or a cultural heritage manager would probably Christiana Mitsakaki, Higher Geodesy Laboratory, School of Rural and Surveying Engineering, National Technical University of Athens, Greece. E-mail: <topocris@central.ntua.gr>.

Amanda Laoupi, External Research Associate, School of Rural and Surveying Engineering, National Technical University of Athens, Greece. E-mail: <alaoupi@otenet.gr>.

like to know the main factor of risk and its spatiotemporal distribution. Cultural heritage objects cannot be evaluated in a void; surrounding landscape must be taken into account, too, especially if the landscape itself is part of the cultural site.

Places of worship, and palaces and castles, for example, have traditionally been built in elevated areas, sometimes surrounded by water for added protection; cities have risen up along trade routes and major waterways; bridges and tunnels have been built to cross a challenging terrain; and peace and tranquility surround the resting places of the rich and powerful of empires past.

All these places of our cultural heritage need to be better protected. Given that protection of historic places is a complex task, a wide range of disciplines-among them geoinformatics-needs to be involved in order to collect data, analyze them, make them available through a common reference system, and document the actions taken to implement effective protection. Efficient data sharing among specialists and its management are crucial for the success of any multi-disciplinary endeavor.

Tools such as the geographic information system (GIS) are particularly useful for compiling, comparing, and integrating data from research areas using geography as a common base. GIS is a virtual space where every kind of information can be referred to a specific point in a known spatial reference system while the data themselves are connected in a logical environment (i.e., the database). These attributes make GIS an appropriate tool to use then attempting to document and monitor a cultural site. It may also be used for predictive modeling to support conservation efforts with respect to a specific or future hazard risk.

To assess risk and long-term effects of decaying, systematic monitoring of our cultural heritage is

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required within a scheme of planned maintenance. Attention should be given to the monitoring or "experimental investigation" methods used to collect data that would help in damage assessment, may contribute to identifying potential threats to protecting cultural heritage, assist decision making in maintenance management, and, provide sound basis for an adequate prevention policy. Until recently, however, the cost of such investigations involving modern surveying and mapping procedures and landscape visualization procedures was admissible only when there was evidence of severe damage or in the case of major world monuments such as the Acropolis in Athens or the Trajan's column in Rome (Skar 2007). Contingency plans aimed at the protection of cultural heritage should always rely upon monitoring programs involving different kinds of measurements, which obviously depend on the target to be investigated with respect to the most probable hazards as well as on the available budget.

In the work reported in this paper, an attempt is made to classify the suitability of monitoring techniques, particularly geoinformatic techniques, according to the criteria that play an important role in the analysis of risk and the protection and maintenance of cultural monuments. The objective is to provide heritage managers with a framework of requirements for the monitoring stage so that they may develop their own strategy for the protection and maintenance of local cultural heritage.

Basic Concepts Cultural Heritage All kinds of evidence related to human action, any "product" of human creativity and expression, widely accepted for their scientific, historic, artistic, and anthropological value, may be considered as cultural heritage Natural landscapes are included in the lists of patrimony objects that must be protected. Natural features (physical or biological formations), geological and physiographical formations, protected natural areas (marine parks, national parks, aesthetic forests, protected monuments of nature, game reserves and hunting reserves, eco-development areas), along with the four types of biodiversity (genetic, species, habitat, landscape), all belong under this umbrella category. Some are living landscapes, but usage has altered them considerably, while others are largely unchanged. Sometimes, "fossil

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landscapes" (e.g., Pompeii or shipwrecks on the sea floor of the Black Sea) are unusually well preserved due to various environmental conditions or geological/physical processes (Laoupi and Tsakiris 2007).

Monuments, caves of archaeological interest, groups of buildings, archaeological sites (openair areas, subterranean, submarine, or coastal), mobile objects, archival material, scientific works, paleoanthropological and paleontological landscapes of memand remains, industrial sites sacred, and traditions, oral languages, ory (e.g., mythical landscapes), museums, and collections are all prone to various types of hazards, with impacts that range from those that are impossible to remedy to those that demand extremely expensive restoration programs.

Hazard and Vulnerability The term "hazard" refers to the unexpected or uncontrolled/inevitable event of unusual magnitude that threatens the life and activities of humans. Hazards possess certain special characteristics: (a) they affect the natural and cultural landscapes; (b) they intensify the degradation processes, especially when human factors play a prominent role; and (c) they may provoke abroad spectrum of losses within human society (http:// wvv.naturalhazards.org/discover/index.html; http://www.unesco.org/science/disaster/index_ disaster.shtml; Burton et al. 1978).

In order to provide accurate assessment of hazard to cultural heritage hazard assessment, the current/potential hazards that may have impact on patrimony's units, either natural or cultural, should be identified and classified before appraised. Both natural and human-induced hazards need to be subjected to this process.

The natural hazards include land movements (e.g., landslides, avalanches, volcanic eruptions, earthquakes, soil liquefaction, coastline regression), sea-level changes, tsunamis, submarine pockmarks of natural gas, gravitational waves, electromagnetic storms, changes in the biochemical synthesis of waters, rapid climatic changes, prolonged drought, floods, hail, unexpected frost or snow, prolonged burning heat, typhoons, tornadoes, stormy winds, soil erosion, desertification, extensive disappearance of plant and animal species, transgression of marshy areas, lethal mutations ofpathogens/pandemics, massive movement of populations, meteoritic fall, wild fires, insects, birds, reptiles, carnivores, and undesirable plant species within the site (Laoupi 2007).

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Examples of human-induced hazards are drainage of marshes, lakes, and rivers, burying of streams, changes of river's course, destruction of wetlands, habitation of sites near volcanoes or faults, intentional fires, land deforestation, dams, extended industrial units, mines and quarries, over-exploitation of natural resources, intensive cultivation of the land, trans-boundary pollution, non-cooperative management of cultural resources among states that share common frontiers, war/conflict, biological war, chemical and/ or nuclear pollution, noise pollution, exhaustion of ground water tables, explosives and other kinds of vibrations, overpopulation, aesthetic alteration of the landscape, etc.

Neglect is perhaps the most subtle threat, whether by deliberate intent, lack of awareness or concern, or lack of the necessary resources. Neglect is not only the failure to undertake necessary steps of protecting cultural buildings and objects, it can also consist of failure to develop appropriate legislation, failure to observe incompatibilities between different statutory measures or policies, or failure to undertake necessary research into preventive and remedial measures [European Parliament Directorate-General for Research (EP-DGR) 2001].

Cultural heritage also continues to become more vulnerable on its own, due to new socioeconomic demands resulting from increasing population density, urbanization and other development pressures, and poverty. Many types of development projects can have a direct adverse impact on cultural heritage. Examples are damaging and thus diminishing the value of the cultural heritage through unregulated building activities, conversion and degradation of traditional habitats, environmental pollution, or disruption of traditional ways of life. Traditional habitats and other environments at risk often are not included in the official definition of "heritage" particularly in the developing world, thus putting cultural heritage at grave risk in those countries (Jigyasu 2003).

Human-induced changes pose the greatest threats, with tourism and urban growth being, perhaps, the two most pervasive mechanisms of change at heritage sites. Tourism creates growth and economic benefits for local communities, regions, and countries while simultaneously making both tangible and intangible cultural heritage vulnerable to irrevocable damage and loss. The economic development of developing countries accelerates this impact, by making heritage sites more accessible to the global tourism industry.

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Exploitation of heritage resources is often more expansive in developing countries, which experience rapid urban growth but have insufficient development regulations in place (Stubbs and Rodway McKee 2007).

Vulnerability is most often conceptualized as being constituted by components that include exposure to multiscaled perturbations or external stresses, sensitivity to perturbation, and the capacity to adapt (Adger 2006). "Vulnerability" is also thought of as a susceptibility to harm or the potential for a change or transformation of the system when it is confronted with a perturbation, rather than as the outcome of this confrontation (Gallopfn 2006). A system (i.e., a city, a human community, an ecosystem) may be vulnerable to a certain perturbation but persists without problems insofar as it is not exposed to it. Although measuring vulnerability is a difficult task, the need for its assessment is obligatory. Recently, in order to simplify estimation procedures, a factor approach has been proposed that considers economic, environmental, social, and patrimonial damages (Tsakiris 2006).

Monitoring Methods and Means Usually, early detection of probable damages due to decaying effects as well as hazard risk assessment requires systemsfor long-term monitoring. It is, however, procedures and technologies that directly observe the cultural target in situ, as well as the surrounding landscape, without causing any significant harm that are preferable. During the last decade, new methods (radar, ultrasonic, strain gauges rooted on optical fibers, GPS, remote sensing, etc.) have been applied in monitoring and diagnosis in order to protect, remedy, and preserve cultural heritage. As a result, a variety of real-time monitoring systems may currently be employed in disciplines in need of geo-referenced information obtainable through geodetic surveying and modeling and tying objects through their coordinates into a common reference system. These monitoring systems offer a set of powerful tools for the protection and preservation of cultural heritage.

However, only in very few cases, have these monitoring methods been applied (ECTP Report 2005). Effective risk management of cultural assets is also hampered by inadequate knowledge of the assets, failure to estimate the true cost of loss and damage, and the difficulty of determining the inherent, non-commercial value of many 31

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etc.) or GPS methods are recommended.

Although these methods record discrete points, scanning techniques using terrestrial I Millio - ,-" - "â&#x20AC;˘ â&#x20AC;˘ "-" 'r"5 Iâ&#x20AC;˘''........

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SCA 100000 light detecting and ranging (LIDAR) sensors AFHOT CLPHOT" and devices, and photogrammetry (close -A.PHO 10 000 range or aerial) can record surfaces with even 1000 millions of points in a very short time. Also, ]TACTILE-=-TACHEOt.synthetic aperture radar (SAR) technology, GPS Ai -.- SIMPLE1 implemented through either space-borne or ground-based sensors, has demonstrated its .. _1 capability in the assessment of ground surquasi-continuous displacement over face 0 blect(area)slze 0.1miml10m 100m km 10km 100km 100kOkn wide areas (Crosetto et al. 2007).

I:IMIIl 1:1000 1:1 Scale (max) Photogrammetry has seen some use in on archaeology because it enables metrical meaFigure 1. Surveying methods for cultural heritage documentati while also yielding a high level of (Boehler et al. 2004): SCAN: close range scanners, CL. PHOT alnd surements detail. The method used to be A. PHOT: close range and aerial photogrammetry; TACHE "0: radiometric costly and time consuming, providing the tacheometric surveying of all kinds; R.S.: remote sensing. final result in the form of a vector plot. Presently, aerial photogrammetry and remote are considered the simplest methods of sensing cultural heritage objects. Moreover, as with other extensive cartography over large areas obtaining types of environmental risk, the risks to cultural The method may prove helpful regions. entire or heritage are highly location dependent, which difficulties in undertaking facing countries in reduces the possibility of rigorous national or with satellite imagmonitoring, ongoing proper international efforts. This condition is more prohelping to bridge photogrammetry aerial and ery nounced in developing countries where both 2001).

(UNESCO gap enormous the underland-use planning and risk policies are The use of stereoscopic images (e.g., mostly rated, with very few funds assigned for natural from aerial photographs) is considered imporhazard investigations. tant in slope instability studies because of the Possible surveying techniques for cultural docudiagnostic morphology created by some mass mentation are shown in Figure 1. The use of any movements (e.g., disrupted vegetation cover, given technique will depend on the scale of the that can clearly be seen in large-scale aerscarps) final product document required, which in turn With the availability of high spaphotographs. ial is a function of object size andcfeasible generalizasatellite imagery (IKONOS, resolution tial tion. If the object is small and not very complex, and the IRS series Indian satSPOT-5, QuickBird, simple hand measurements or tactile methods research has opened for the of area a new ellites), (the position of a probe touching the object is inventory maps (Metterlandslide of production recorded) are sufficient. Geotechnical monitor2005). al. et nicht ing instruments (inclinometers, extensometers, Finally, all natural hazards may be studied, to strainmeters, 3D shear displacement meters, degree, by remote sensing because nearly some etc.) fibers, strain gauges rooted on optical all geologic, hydrologic, and atmospheric phedesigned to observe the structural behavior of nomena that create hazardous situations are man-made structures and unstable natural formarecurring events or processes that leave evidence tions (land and rock slides, glaciers, etc.) in conof their previous occurrence(s) which can tact with the object may fall under this category. recorded, analyzed, and integrated into future be A number of sensors and probes are sensitive to (http://www.oas.org). planning changes of pressure and heat, providing data for between ground and airborne distinction The hazard assessment studies of patrimony (e.g., is rather vague. New sentechniques satellite or open cultural sites that may be prone to fires or of new sensors (e.g., fusion the mostly, and, sors museums and institutions that are apt to fires aerial photogramGPS-controlled Kinematic and/or theft, etc.) which, in some cases, may also digital comlarge-format sensors, inertial metry, be considered as supporting tactile methods. as new well as etc.), LIDAR, cameras, pound When points are further apart, conventional cartoexchanging and delivering of means topographic survey (total stations, digital levelling,

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Surveying and Land Injormation .cience

Surviying and Land Information Science

graphic information, new algorithms-which not only render geometry and radiometry but also provide quality estimates-and new relations between photogrammetry, image processing, remote sensing, computer graphics, and robot vision have created a fertile field in which architects, archaeologists, risk-prevention researchers, land managers, and other non-skilled geoinformatics professionals may join in a passive (users) or active (designers and developers) fashion (Rubio et al. 2005).

Modern surveying methods require investment in specially trained personnel and costly technical equipment, which may make them less attractive to smaller entities involved in monitoring cultural heritage, but, on the flip side, not using such techniques may result in unnecessarily high costs of time and money (Boehler et al. 2004).

Water-related hazards-be they human-induced or natural (flooding, tsunami, landslides, debris flow and soil liquefaction, dam construction, loss of the wetlands, acid rain, sea-level rise, etc.)can be monitored and evaluated using remote sensing techniques that serve a broad spectrum of applications, as well as methods specifically developed to measure water levels and other characteristics of large bodies of water. Tide gauges, buoys measuring water salinity, temperature, and current velocity, as well as satellite altimetry and remote sensing are some of the geoinformatics techniques that provide information on sea-level changes and changes in coastal areas. In-situ stations with stream gages, precipitation gages, radar, and multispectral satellite imaging together with various geomorphologic observations are some of the monitoring methods used in flood studies and in the creation of flood hazard maps.

It is not sufficient to examine and document only the object by itself; the landscape surrounding the object should be considered, studied, and documented as well. Surveying, mapping, and visualizing surrounding topography over a given period of time will yield historic evidence that may be used to reconstruct landscape development from ancient to present times. Data depicting present topography (erosion, slides, flooding) or land use (agriculture, industry, traffic) can then also be used to foresee and possibly prevent obstacles to conservation efforts (Boehler et al. 2004).

Virtual representation of landscapes comprising objects of cultural heritage is much more important than using virtual images of the objects themselves. Virtual landscape representation can be implemented using digital elevation models

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(DEM). For detailed DEMs, tacheometric surveys or stereophotogrammetric measurements from aerial photographs should be used. Larger areas can be surveyed using smaller-scale aerial photographs or GPS measurements. Some Earth observation satellite sensors supply images suitable for stereoscopic vision which allow automatic DEM generation by matching techniques, thus providing a robust method of creating DEMs for large areas (Boehler et al. 2004).

Because all types of cultural heritage evolve and survive in a spatio-temporal framework, miultilevel understanding of change within the cultural landscapes-either as a long-term decay process or as a result of hazardous events throughout human history-requires complicated evaluation techniques that can register all possible factors affecting the existence, function, and appearance of cultural heritage units (Laoupi 2007).

Recent trends in GIS technology have led to the development of a temporal GIS (TGIS), a system capable of tracing and analyzing the changing states of study areas, storing historic geographic states, and anticipating future states. A TGIS could be used to analyze the processes causing geographic change and derive patterns in the data.

Obviously, all information stored in a GIS-or TGIS-has to be evaluated in terms of accuracy, reliability, and completeness -in short, quality.

Integrating information acquired from all types of monitoring systems into a TGIS generates a powerful multiscalar (multitemporal and multispatial) analysis tool that can be used to create an urban dynamics model that visualizes future consequences of environmental and human-made threats. The tool would have two components; a broad-scale spatial analysis that could be used to extrapolate the causes and effects of human activity over time from regional dynamics. The second component would be a regional settlement model of historical and contemporary habitation patterns. This analytical tool is technically superior to the random-sample procedures used so far to analyze cultural heritage because it provides valuable information about past and present environments, land use, and settlement patterns (Stubbs and Rodway McKee 2007).

Monitoring Outline As of today, a notable discrepancy exists in the choice and application of appropriate technological interventions for the protection and conservation of the various categories of patrimony.

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I

Large-scale monitoring of cultural heritage in situ is still a relatively weak research field, with no international standards established as yet. Consequently, uncertainty remains concerning the impact of various natural and man-made hazards on our cultural heritage. Furthermore, in the absence of relevant, accurate data, it is difficult to design a preservation and management strategy in conformity with international agreements on cultural heritage sustainability (Skar 2007).

One of the first steps to be undertaken in the management and protection of cultural heritage is to distinguish the various categories of cultural heritage found in a given country, region, or continent. This can be efficiently done by considering the environment. Three broad categories of environment have been identified: outdoor, indoor, and buried (including terrestrial, coastal, and marine) (EP-DGR 2001).

In order to link researchers with decisionmakers and end-users, a focus on the necessary process stages is required (EP-DGR 2001). A realistic applied research method would thus distinguish the process into discrete stages: understanding materials; monitoring changes; modeling and predicting behavior; managing cultural heritage; and preventing damage. Geoinformatics is at the heart of the monitoring stage.

This is because geoinformatics methodology can provide periodic and intermittent monitoring data as well as continuous data for a GIS-based geo-database. In view of the multicriteria risk evaluation analysis necessary for most types of hazards, choosing the most efficient monitoring method for a given risk in terms of accuracy, efficien(y, speed, economy can be tricky.

An attempt is made below to outline methodsmainly in the field of geoinformatics (except in the case of the tactile methods where geotechnical and water-related hazard monitoring are also

considered)-that would be suitable for monitoring hazards affecting cultural heritage. The parameters/criteria associated with certain characteristics of the studied cultural targets and aspects of hazard risk assessment are given as well (Tables 1 and 2).

Monitoring methods can be broadly categorized into tactile (strainmeters, inclinometers, strain gauges, tide gages, precipitation gages, electronic probes, sensors, etc.), surveying (total stations, LIDAR, close-range photogrammetry, electronic sensors, cameras, etc.), satellite positioning (GPS, SLR, VLBI, etc.), aerial photogrammetry, and remote sensing methods (Table 1). Although remote sensing is typically grouped together with satellite positioning methods, it should be noted that GPS provides positional and velocity information of higher accuracy and reliability than does remote sensing. Another hazy distinction exists between aerial/satellite photogrammetry and remote sensing. High-resolution satellites such as IKONOS and QuickBird which collect imagery with spatial resolution of 1 m or better provide highly improved accuracy.

The criteria impacting risk evaluation analysis are given in Table 2, together with the monitoring methods that best fit these criteria.

Short explanations referring to the selected criteria follow: The types of naturalhazardsare grouped as follows: water-induced hazards, geologic hazards, Earth changes (climatic changes, sea-level changes, coastal regression, etc.), atmospheric phenomena, erosion, and wildfires.

The types of cultural targets are distinguished according to their environment: outdoor, indoor, and buried.

The level of risk is chosen as normal, transitional, or prohibited, as determined by a variety of risk

Monitoring Method Tactile

Type of Hazard

Satellite Positioning

Aerial Photogrammetry

Remote Sensing

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Surveying

Water-induced hazards Geologic hazards

Yes (in situ observations)

Earth changes Atmospheric phenomena Erosion Wild fires

Yes

Yes

Yes Yes

Yes Yes Yes

Yes (heat sensors)

Table 1. Monitoring methods with respect types of hazards that often threaten cultural objects.

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Monitoring Method Parameter Type of cultural targets

Tactile

Surveying

Indoor + outdoor

Indoor + outdoor + buried

Level of risk

Satellite Positioning Outdoor

Aerial Photogrammetry

Remote Sensing

Outdoor + buried

Outdoor + buried

Intermittent monitoring of low cost for normalrisk Monitoring should be requisite in cases of transitionaland/orprohibited risk

Spatial relevance

+

+

0

+

+

+

0

0

Accessibility

Contact/remote

Contact

Remote

Remote

Remote

Monitoring time schedule

Continuous

Periodic/intermittent

Continuous GPS or periodic/intermittent

Periodic/ intermittent

Periodic/ intermittent

State of hazard

Proactive

Size of target

Proactive risk assessment/damage evaluation Small to average

Average to large

Accuracy and reliability of data

Low or high

High

High

High

Middle to low or high

Tentative cost estimate

Low to average

Average to expensive

Average to expensive

Expensive

Low to average

Table 2. Assessment of the appropriate monitoring methods with respect the criteria chosen to better associate hazards with the cultural targets.

criteria [European Spatial Planning Observation Network (ESPON) 2006].

Spatialrelevance of risk (high = +, low= 0, none = -) (ESPON 2006). The spatial relevance criterion refers to whether the hazard-should it turn into a disaster-will affect a continuous extensive disaster area or whether it occurs sparsely in space (e.g., meteorite impacts, car accidents, etc.). Thus, all monitoring methods may be used in high spatial relevance (+) according to the other criteria. In the case of low relevance (0), the first two method types appear to be more appropriate, while remote sensing data may be also used if they are available. No action is considered if the hazard has no spatial relevance.

The accessibility criterion refers to the ease of access of the cultural target in conjunction with the type of hazard (contact or remote monitoring). Thus, tactile methods may be used for contact monitoring (e.g., electronic probes, sensors, etc.) or remote (e.g., for monitoring the surrounding landscape in case of fire, landslide, etc.). Satellite and remote sensing techniques usually deal with extensive cultural targets and the surrounding landscape.

With respect to the monitoring time schedule (continuous, periodic, intermittent), it should be mentioned that the monitoring time-table is dependent on the recurrencerate of the hazard as

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well as the expected magnitude of its consequence on the target should it turn into a disaster.

The state of hazardmakes the distinction between the state of hazard (proactive risk assessment) and the outbreak of the disaster (mitigation and damage evaluation) The size of cultural targetrefers to small-size targets (artifacts or fragments, statues, or buildings) covering an area of about 0.1 to 100 M 2 , average-size targets (100 m 2 to 1 kM 2), and large-size targets (1 to 100 kM'2 ). It should be mentioned

that, instead of the size of the target, the scale of the final product document might be used but this may vary according to accuracy and generalization requirements, making the categorization via the actual size of the cultural target preferable.

In several cases (e.g., geologic hazards), high accuracy and reliability of positional and velocity information is needed. All geoinformatics methods (ground and satellite) provide data of high accuracy and statistically reliable. The same is true for most of the geotechnical instruments (tactile). This may not hold for other types of sensors and remote sensing, where a more-qualitative interpretation is required.

Cost ranges: low (<50.000f), average (50.000 to 200.000â&#x201A;Ź), and expensive (>200.000f). It should be noted that no instrumentation price is included, and these annual costs are very

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rough estimations. For ground and aerial photogrammetry as well as GPS methods, field campaign expenses are highly dependent on the size of the area to be observed and the problem to be dealt with (frequency of campaigns).

Thus, respective cost estimations are extremely sketchy.

From Table 2, it is clear that choosing an appropriate monitoring method is not easy. In many cases, a combination of satellite techniques and remote sensing is preferred mainly because they provide information not only about the cultural monument but also about the surrounding landscape. Type and size of the cultural target and level of risk are of paramount importance, while data quality is primarily imposed by the character of the hazard and, thus, the possible size of the impact on the target. However, even if the parameters taken into consideration suggest otherwise, the final choice of the monitoring technique and schedule cannot be decided without considering its fiscal requirements.

Discussion and Conclusions It is widely accepted that national inventories of cultural targets are the keystone of heritage management simply because knowing what one's resources are is a prerequisite for their effective safeguarding. This notwithstanding, in many parts of the world, they remain incomplete, dusty, hard to access, and unrelated to overall spatial planning (Taborof 2000).

It is, also a fact that the preservation of cultural heritage requires a deeper knowledge than we currently have of how various hazards may affect the patrimony and which types of modern geo-information technology are best suited for monitoring cultural heritage. Thus, universal solutions are not the answer while deterministic approaches and an eagerness for standardization have, often, oversimplified reality. In addition, in developing a suitable strategy for the protection and preservation of cultural heritage, government authorities need to recognize not only the legislative requirement to classify and protect heritage but also the value that local communities place on heritage resources as a means of defining their place in history and realizing their cultural differences. Furthermore, because heritage is vulnerable to development, it must be taken into account when planning for future development and growth (Wellington Regional Strategy 2005).

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Total protection and conservation are unrealistic ambitions, particularly in light of the complex environmental interactions that take place continuously. Protection and conservation can only be achieved through effective communication among specialist disciplines, decisionmakers, and end-users about their requirements for protection and access. Maintenance may currently be an easier and ptobably more economic solution to pursue although it is still considered less desirable than restoration. This is due to its periodic nature which is perceived as expensive, particularly when compared to the indistinguishable improvements it often produces (EP-DGR 2001).

In many countries, including Greece, the preservation and protection of cultural heritage leave much to be desired in terms of efficiency. The shortcomings in the process may be: (a) administrative, (b) socio-economic, and (c) archaic-environmental. Among the administrative drawbacks are: (a) lack of unified national inventories, and few of those data are in digital form; (b) lack of unified source of information (multiple data providers); (c) lack of a widely acceptable method for hazard assessment of cultural heritage; (d) shortage of qualified people to address the topics of hazard management of cultural heritage; (e) low level of data sharing and data quality; and (f) time-consuming bureaucratic procedures when dealing with services, such as the Greek Ephorates of Antiquity.

Examples of the socio-economic problems are (a) low level of collaboration among the different departments (i.e., civil defense, fire, police stations, Supervisory Offices of Antiquities) concerned with the contingency planning; (b) low level of coordination/cooperation concerning the research teams; (c) socio-economic conditions hindering the funding of research projects; (d) and today, the majority of the most popular tourist cultural landscapes are often within areas of fast development rates, industrial installations and activities, summer resorts, and even hazard-prone areas, while other areas face abandonment, lack of tourist infrastructures, lack of stable financial support and managementoriented funding, as well as long-term pollution and illegal activities.

Finally, the archaeo-environmental drawbacks may include (a) archaeological features within modern landscapes/seascapes fragmented by nature and (b) landscapes representing multiple co-existing cultures simultaneously expressed or overlaid historically.

Survtying and Land Injarmation &aen ce Surviying and Land Infonnation Science

Given these limitations on traditional methods, the use of integrated GIS solutions for the protection and management of cultural heritage may prove valuable, especially for countries such as Greece. The monitoring stage is indispensable for risk evaluation, early-warning purposes, and risk management in order to ensure efficient and lasting Cultural Heritage Management. The necessity and importance of a well designed monitoring process is highlighted by DEMOTEC (Development of a Monitoring System for Cultural Heritage through European Cooperation), and is supported by the European Commission under FP5 (Mets and Skar 2003).

This paper demonstrated the need for accurate monitoring of cultural heritage, addressing key issues for future heritage managers and institutions. A national program for efficient Cultural Heritage Management should include, as a longterm objective, the establishment of guidelines for the application of monitoring and diagnostic methods, for both decaying and hazard problems of cultural assets. Expert systems and user-friendly software for the analysis of acquired data should be part of the guidelines. Periodic assessment of cultural heritage as part of a management system should be a pre-requisite, as should the expansion of databases with all available data about typical damage, testing problems, assessment methods, monitoring and diagnosis methods, case studies, structural models, research projects, etc. should be a requirement.

In order to prevent further loss of cultural heritage and ensure adequate level of conservation, government policy should include the following steps: (a) Integration of the Cultural Heritage Management (CHM) into the Environmental Management so that long-term interactions between living and past populations and their environments could be clarified. (b) Development of a more efficient and internationally accepted policy and legislation on CHM. (c) Budget provisions for CHM from national fiscal programs. (d) Dissemination of information on CHM topics and the activation of public awareness as well as involvement of local communities in all stages of CHM. (e) Coordination with respect to the international community in order to secure necessary funding and ensure agreement with global guidelines and legislation, as well as professional standards.

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