A DIDACTIC PROJECT FOR LANDSCAPE HERITAGE MAPPING

IN POST-DISASTER MANAGEMENT

Piero Boccardoa,b, Filiberto Chiabrandoa, Anna Facelloa, Loretta Gnavia, Andrea Linguaa, Paolo Maschioa, Fabio Pasqualec and

Antonia Spanòa

aPolitecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italy, e.mail: filiberto.chiabrando@polito.it ,

anna.facello@polito.it , loretta.gnavi@polito.it , andrea.lingua@polito.it , paolo.maschio@polito.it ,

antonia.spano@polito.it bITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action), Via Pier Carlo Boggio 61,

10138, Torino, Italy, e.mail: piero.boccardo@polito.it cSiTI Istituto Superiore sui Sistemi Territoriali per l’Innovazione, Via Pier Carlo Boggio, 61, 10138 Torino, Italy,

e.mail: fabio.pasquale@siti.polito.it

KEY WORDS: cultural heritage, disaster management, education, risk mapping

ABSTRACT:

In recent years natural and human induced hazards have increasingly turned into disasters with rising frequency and intensity. These

disasters pose threats to prominent cultural and natural heritage sites of the world and, therefore, require the intervention of skilled

technicians and staff with specific scientific and cultural training. It is necessary to contribute towards reducing slow as well as

catastrophic risks in short and long term, through the training of staff for intervention aimed at emergency management and

mitigation of the impact and development of solutions with the collaboration of professionals working in this area.

This paper presents a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA

(Information Technology for Humanitarian Assistance, Cooperation and Action). The main goal was the training in geospatial data

acquisition and processing for students attending Architecture and Engineering Courses, in order to start up a team of “volunteer

mappers”. Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to

improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing using

the modern geomatic methodology and techniques (terrestrial and aerial LiDAR, close-range and aerial photogrammetry,

topographic and GNSS instruments etc.. All the acquired data and processing results have been implemented in a WebGIS platform

to share information with local authorities and the Civil Protection. The proposed area for testing the training activities is inside the

Cinque Terre National Park (Vernazza), registered in the World Heritage List since 1997. The area was affected by flood on the 25th

of October 2011.

1. INTRODUCTION

Some 75 per cent of the world’s population live in areas that

have been affected at least on one occasion from 1980 to 2000

by earthquake, tropical cyclone, flood or drought. Natural

disaster and their consequences are intimately connected to

human development processes. The loss of human beings and

the destruction of economic and social infrastructure are

expected to worsen as climate change increases the frequency

and magnitude of extreme meteorological events, such as heat,

waves, storms and heavy rains. The community has already

developed a set of instruments to address various aspects of

disaster preparedness, response and recovery (UNDP, 2004).

Therefore, some organizations in the world (UNESCO,

ICOMOS, ICCROM, ecc.) emphasize the importance of the

protection of cultural heritage as a priority of our society. The

heritage conservation field places great importance on the use of

principles in guiding practitioners to appropriate interventions

for heritage properties. Conservation professionals recognize

these principles as being contained within the family of

doctrinal texts loosely linked to the Charter of Venice (1964),

for which ICOMOS is generally recognized as custodian.

ICOMOS has taken responsibility, primarily through the efforts

of its specialized international Scientific Committees, for

extending the basic general principles presented in the Venice

Charter by elaborating complementary texts in related fields

(Massue et al, 2001).

In this context, the “Cinque Terre project” is directed to provide

specific contributions to improve the attention for the natural

and cultural heritage, environmental protection and

enhancement, through the safeguard of the landscape and of the

architectural and archaeological heritage, damaged or under risk

(Spanò and Costamagna, 2010). The purpose is to develop

capacities in the Geomatic field using innovative methodologies

and techniques for achieving advanced metric surveys using

multi sensors and multi scale data (from space, aircraft and

terrain) (Boccardo and Giulio Tonolo, 2008).

The project has involved graduate students attending master

degree in Architecture and Engineering at the Politecnico di

Torino; the students can rely on basic qualification in

topographical and mapping or GIS technologies derived from

core subjects, and the key point for achieving the effectiveness

of the training consists in the organization of all day long

activities on site. The full immersion work, managed in small

groups of students (4 or 5) per each tutor, adding the pre and

post site experimental sessions, allow to obtain a good level of

expertise for the new crisis mappers team.

2. TEST SITE: VERNAZZA (CINQUE TERRE

NATIONAL PARK, WORLD HERITAGE LIST)

The Cinque Terre National Park was selected as test area for

two principal reason: the high value of landscape and

environment, then the severity of the flood event happened on

the 25th October 2011 and the severe damages occurred after

that.

The Cinque Terre area (Monterosso, Vernazza, Riomaggiore,

Corniglia e Manarola) covers approximately 15 km along the

extreme eastern end of the Ligurian coastline, between Levanto

and La Spezia.

The position of the five small towns and the shaping of the

surrounding land-scape, characterised by steep and uneven

terrains, encapsulate the continuous history of human

settlements in this region over the past millennium

(Dongiovanni and Valle, 2007; RSA Parco Nazionale delle

Cinque Terre, 2004). This Park was recognised by UNESCO

on its ‘World Heritage’ list, on the basis of cultural landscape

criteria and its out-standing value, representing the harmonious

interaction between people and nature (World Heritage Report

1997).

Figure 1. The orthophoto of Vernazzola stream (a) pre-event

August 2011 and (b) post event November 2011 (Source:

BLOM-CGR Parma).

The coastal area is typically characterized by high and steep

slopes artificially re-shaped during the centuries by human

activity, through the construction of dry stone walls.

In the Cinque Terre area, slope instability is mainly due to the

presence of land-slide-hill and lithological composition of the

substrate to which has been added, over the last decades, the

gradual loss of maintenance and defence of the territory

operated by human activity (Federici et al. 2001).

The drainage network is poorly developed and consists almost

exclusively of canals, ditches and channels. These are rivers,

with a very limited scope, which, in some cases, may remain

almost dry during the dry season.

2.1 Flood event (25th October 2011)

The surveys have been focused in the area of Vernazza, a

coastal village which reported extensive damages since the

flood event of 25th October 2011 that has been caused by the

overflow of the Vernazzola stream (Figure 1).

The heavy precipitation event, occurred in autumn 2011 over

the Ligurian Sea and the rainfall accumulated on the 25th of

October 2011, over the area of Vernazza, exceeded 500 mm in

12 hours, with peaks above 100 mm/hour, leading to a real

hydrogeological disaster over the zone by the most organized

convective systems.

All along the mountainside and hillside of the area characterized

by an artificially altered substrate (the typical terracing of the

Cinque Terre hillside), the rain-falls have caused an instability

both of land and vegetation.

As a consequence several slides were occurred in the area. The

surface runoff, due to the inclination of the terrain caused a big

amount of detritus resulting from landslides and soil cover and

in few hours the centre of the town (figure 2) was reached and

partially flooded (Ortolani, 2011).

Figure 2 shows the harbour of Vernazza before and after the

flood event.

Figure 2. Vernazza and its harbour before (a) and after (b) the

flood event

The Vernazzola watercourse and the provincial road along the

river, which were seriously damaged by the flood, were the

main objective of ground documentation of the calamities.

Moreover, along the stream of water, several artefacts,

including bridges, stone masonries opposing the slope

pressures, gardens, houses, terraces and other built structures

have been heavily damaged or completely destroyed (Figure

3).Finally, in order to complete the survey, the acquisition of the

main street of the Vernazzola village was realized using the

same methodology.

(a)

(b)

(a)

,

(b)

Figure 3. Examples of damages to buildings.

3. METHODS

3.1 Aerial data acquisition

Since the area is large and complex, the most suitable strategy

for assessing impacts and damages caused by the flood, is the

analysis of images acquired by satellite or aerial platform (pre

and post event), conveniently integrated by ground surveys.

LiDAR data and high-resolution aerial orthophotos, adding to

the basic and thematic multi-scale maps, have been collected for

supporting the project development, in order to plan and locate

the deepening area, to detect the major damages and to check

the accessibility.

The aerial orthophotos and LiDAR flights (post event) were

provided by Blom CGR Parma and Helica for the Friuli

Venezia Giulia Region (Figure 1).

Moreover, the Liguria Region has provided several

geodatabase: the basic maps (Carta Regionale 1:25.000 ed

1994/95; CTR 1:10000 ed 2007; CTR 1:5000 ed. 2007), the

Regional Geological Map 1:25000, the Inventory of landslides

1:10000 (IFFI project), the monitoring network of the slopes

1:10000 (Remover) and post flood erosion/accumulation maps,

performed by the difference of LiDAR data acquired in 2008

and2011. Even this last products have been achieved by the

Friuli Venezia Giulia Region.

3.2 The geodetic network

The geodetic network of the area (Figure 4) has been defined by

the GPS/GNNS method, it was connected to the permanent

ITALPOS stations of BRUGNATO ( 11 km from Vernazza)

and LA SPEZIA ( 15 km from Vernazza). The vertex situated

on the school has was used as local master station. The vertex

coordinates was calculated using Leica Geo Office obtaining a

good accuracy for the application (RMS: 5 mm in 2D, 10 mm in

height). Inside the centre of Vernazza, 3 vertexes were surveyed

using total station with a redundant network schema.

The ellipsoidal heights was converted in geoidal heights using a

local model of geoid (ITALGEO95) furnished from IGM

(Istituto Geografico Militare, the national military geographic

institute).

The network represent the basis for the next maps updates and

for the multi-scale integration that will support the recovery and

rehabilitation projects of the land.

Figure 4. The geodetic network frame.

3.3 Terrestrial laser scanning (TLS) surveys

The scanner Focus 3D (Faro Cam2) effectively fitted to the

needs of damages documentation due to the portable, the handy

characteristics and the simple use. The range of scan distances

is variable from 0.6 to 120 m for reflective surfaces (> 90%),

the error in linear distances is equal to ± 2 mm at 10 m and 25 m

for reflectivity of 10% and 90%; the scan speed is up to 900 000

points per second. In addition, the noise is low and it is possible

to acquire radiometric in-formation thanks to the included

digital camera with the optical axis coaxial to the laser beam.

The Faro instrument was used for surveying the Vernazzola

watercourse (about 2 km from the beginning of the overflow to

the sea estuary), and the area of the village where we planned to

document the state of built heritage (the main street, the square

with the harbour and the castle built on the top of the little hill

dominating the town); finally we surveyed a little new beach

created by the accumulation of debris due to the flood event

(Figure 8).

The scans resolution has been chosen medium-high in order to

be suitable for both natural and man-made land elements (the

scan density was set to obtain 1 point for each 6 mm at

distances of 10 meters). During a first step of elaboration a

regular set of cross sections at the distance of about 10 m have

been briefly extracted, without performing accurate clouds

filtering and colouring procedures.

The availability of automated tools in terrestrial laser data

management software, allow the use of recording techniques

that are endowed with procedures of automatic recognition of

geometric correspondences (best fitting).

However, the detected object features, characterized by very

few geometric elements easily identifiable and the abundance of

repetitive and similar elements (the stones of the river) have

advised the use of procedures strictly controlled by measured

targets. By means of these control points we achieved the

transformation in a single coordinate system based on the

reference system WGS84-ETRF2000.

Other targets, with a spherical shape and unknown position,

have been acquired during points clouds collection with the sole

function of tie points, aimed to the registration of adjacent

scans. The presented workflow together with a good distribution

of tie points and control points enabled rapid registration and

recording of scans, obtaining a contextual georeferencing of

data and an accurate control of the residuals.

Furthermore, two scans were acquired using the RIEGL LMS

420i in order to describe the roof of urban centre (not surveyed

from other TLS scans) and a visible rock face near a landslide to

modelling of fractured rock masses.

Table 1 shows some information about raw data and results of

the performed processing. Figure 5 shows a single coloured

points model, the mesh surfaces and an overview of recorded

clouds representing the entire section of Vernazzola.

Total Scans 50

Used GCPs/CPs 94

Total raw points 1 Billion

Dimension (.xyz file format) 50 Gb

Total points after the post processing (cleaning,

noise reduction, decimation etc.) 260

Million

Dimension (.xyz file format) 13 Gb

Table 1. Data showing large size of LiDAR ground collection.

The large set of cross sections extracted from the recorded point

clouds along the Vernazzola stream (Figure 6) has been used to

develop an hydraulic model, using HEC-RAS software. The

simulations implemented intend to evaluate the stream cross

sections more vulnerable to flood events. The roofs of Vernazza

have been collected using RIEGL scans as shown in figure 7.

Figure 5. A collection of images showing TLS data processing

results. Coloured models, mesh models and (top) overview of

recorded clouds representing the entire section of Vernazzola.

3.4 Report on the new beach valorisation

The heavy precipitation event, occurred in autumn 2011, caused

the surface run-off upstream the Vernazza village; a big amount

of detritus resulting from landslides filled the little creek,

generating a new beach. From the new beach many small and

coloured buildings (Figure 8), standing very closed each other

can be observed; they have been constructed on the top of the

cliff, making a typical scenery of Ligurian villages, that are

usually placed in a surrounding landscape characterised by steep

and uneven terrains. The access to the new beach is possible

through two different tunnels. The first one enable the

Vernazzola river to flow in the sea, while the other underground

passage connects the new beach to the centre of the village

(white ellipse in Figure 8).

In order to realize a complete survey of this new beach, we

opted to use the same acquiring resolutions and equivalent

registration strategies employed in other areas, to achieve an

high resolution model (Figure 9).

Figure 6. The extracted cross sections of Vernazzola stream

Figure 7. The roofs of Vernazza extracted from a RIEGL scan

Figure 8. A view from the sea of the new beach

Figure 9. An example of TLS acquisition

After the flood, this area have been under careful attention

because the uneven coastline of the region offer little place to

accommodate people, and a large stony beach, easily and

rapidly approachable from the train station, is a very interesting

place for the local administration.

After the needful stability controls of the rocky slope and safety

conditions of the area, this place can emerge as a cultural and

tourist resource for the village.

TLS points were used to generate a surface of the beach area

and near rock faces. Figure 10 is a semi-nadiral view to

emphasize the different directions of the tunnels.

The contour lines were extracted by planar sections and the

coastal line was collected using the limit of TLS data (Figure

11).

Section profiles derived from high scale and high resolution

models are not suitable for digital maps, because their geometry

is complex and they present an huge amount of vertexes, due to

triangulated surface. The generalization algorithm PAEK

(Polynomial Approximation with Exponential Kernel;

Bodansky et al.,2007) was applied to obtain a natural and

suitable shape of contours by smoothing lines (Figure 12).

Figure 10. The beach surface

Further more in order to evaluate the seabed in the areas of the

harbour and near the new beach a low cost sounder (GPSmap

421s by Garmin) mounted on a little boat was employed; the

followed trajectory was recorded by a kinematic GNSS

positioning based on geodetic receiver. Figure 13 shows the

obtained result with the used instruments.

Figure 11. Contour lines with new sea border line.

Lastly two diving missions (figure 14) were realized in order to

explore the seabed using GoPro video cameras:

- the first was performed in the normal direction to coastline, in

front of the beach. A sandy and downgrading seafloor (until 18

m), without abundant flora and wildlife was detected.

- the second mission was performed about 500m southern the

beach and allowed the finding of a car (Figure 15) and the trees

rattletrap.

Figure 12. An example of contour lines generalization using

PAEK algorithm

Figure 13. Survey of seabed near coastline using low cost

sounder

4. CONSTRUCTION OF GIS

In the field of natural disasters and emergency management

there is a strong interest in geospatial data sharing, with the aim

of avoiding duplication of efforts and allowing a quicker

operational response. GeoNode (http.geonode.org) is an open

source platform that facilitates the creation, sharing and

collaborative use of geospatial data.

Figure 14. The two diving missions itinerary

Figure 15. The sunk car

The aim is to surpass existing spatial data infrastructure

solutions by integrating social and cartographic tools. The

promotion of data sharing is a main factor. On the one hand data

sharing means that a user is put in condition of being able to

upload data into the system and to give other users the

possibility of exploring these data. Contemporary the user is

provided with the capacity of taking advantage of data shared

by others either through online tools or by downloading them

locally in formats suitable for desktop applications (Heinzelman

and Waters 2010).

In this case, the data collected from available database

collection and from terrestrial surveys will be implemented in a

WebGis. Thus, through a dedicated platform, the end user may

consult and interrogate in a simple and rapid way all the

available information.

5. CONCLUSIONS

The enhancement of documentation processes and the

development of procedures for the planning of emergencies

management has been continuously updated according to the

renewed methods and technical tools.

Regarding the on site training, all the students attending the

apprenticeship are now able to manage independently the

acquisition of topographical and TLS data.

The integration of data obtained by advance ground metric

surveys, with those derived by the analysis of aerial or satellite

images will lead to the achievement of a WebGis, aimed to the

collection and sharing of spatial information suitable for the

updating of the existing maps collection. Even in this phase the

students were involved in maps generation from different

sourced data, assessing metadata editing and evaluating overall

data quality. All the data collected during the activity will be

available for local and regional authorities and for the Civil

Protection through the GeoNode platform, in order to provide

useful information for disaster management and emergency

response.

In perspective, this experience will seek the feasibility of

implementing 3D metric data archives pertaining architectural

heritage, yielded by high detail surveys intending to identify the

architectural features of building complexes, within those

systems currently adopted for high scale 3D urban mapping, and

following their paradigms in geometric and semantic

organization (van Oosterom et al., 2005).

ACKNOWLEDGEMENTS

In order to be able to perform the different steps of project,

including the data acquisition phase, we thank the Liguria

Region for making available all the documentation, basic and

thematic cartography. We also thank the town of Vernazza,

represented by Matteo Spona; the FAROEurope-CAM2,

specifically Alberto Sardo, who made available a second laser

instrument for both rounds of the internship (June and July

2012). We also thank Blom CGR for facilitating the use of low

altitude photogrammetric data and post event Lidar data.

REFERENCES

Boccardo, P., Giulio Tonolo, F., 2008. Natural disaster

management: activities in support of the UN system. In:

Advances in Photogrammetry, Remote sensing and Spatial

information sciences: ISPRS Congress book / Zhilin Li; Jun

Chen; Emmanuel Baltsavias. Taylor & Francis Group, London,

pp. 385-396.

Bodansky, E., Gribov, A., Pilouk, M., 2002. Smoothing and

Compression of Lines Obtained by Raster-to-Vector

Conversion, LNCS 2390, Springer, p. 256-265, 2002.

Bornaz, L., Lingua, A., F. Rinaudo, 2003. Multiple scan

registration in LIDAR close-range applications. In: The

International Archives of the Photogrammetry, Remote Sensing

and Spatial Information Sciences, Vol. XXXIV, Part 5/W12,

pp. 72-77.

Dongiovanni, A., Valle, M., 2007. Il Piano di Gestione del sito

UNESCO “Portovenere, Cinque Terre e le Isole” Subambito

Cinque Terre, SiTI – Istituto Superiore sui Sistemi Territoriali

per l’Innovazione.

Federici, P.R., Baldacci, F., Petresi, A., Serani, A., 2001.

Atlante dei Centri Abitati In-stabili della Liuria, in Provincia

della Spezia- Regione Liguria, Consiglio Nazionale delle

Ricerche, Gruppo Nazionale per la Difesa dalle Catastrofi

Idrogeologiche, Università degli Studi di Pisa, Dipartimento di

Scienze della Terra, Unità Operativa 2.13

Heinzelman, J., Waters, C., 2010. Crowdsourcing Crisis

Information in Disaster- Affected Haiti, (Special Report 252),

Washington, DC, United States Institute of Peace (USIP).

Massue, J. P., Schvoerer M., 2001. Protection of Cultural

Heritage, Handbook of school of civil protection, Module bl-4/c

Ortolani, F., 2011. Alluvione nelle Cinque Terre-Lunigiana:

evento da manuale, difesa da migliorare con l’Allarme

Idrogeologico immediato (www.climatemonitor/?p=20863).

RSA Parco Nazionale delle Cinque Terre, 2004. Relazione sullo

stato dell'ambiente - Parco Nazionale delle Cinque Terre.

www.parconazionale5terre.it/upload/AG21Rsa.pdf

Spanò, A., Costamagna, E., 2010. Geomatic training

experiences for a high vulnerability cultural heritage item. In:

Remote Sensing And Geo-Information For Environmental

Emergencies, Torino, 2-4 Febbraio 2010.

United Nations Development Programme (UNDP), 2004.

Reducing Disaster Risk a Chal-lenge For Development, Global

Report, New York, Printed by John S. Swift Co., USA.

van Oosterom, P., Jansen, E., Stoter, J., 2005. Bridging the

worlds of CAD and GIS, in Large-scale 3D Data Integration:

Challenges and Opportunities, S. Zlatanova and D. Prosperi,

eds., ch. 9, pp. 9-36, Taylor&Francis - CRC Press, Boca Raton

US-FL, 2005.

World Heritage Report, Napoli 1-6 dicembre 1997, Portovenere,

Cinque Terre and the Islands (Palmaria, Tino, Tinetto) n.8267.