A method for multi-source data exploitation, support for crisis situations management. Case study: floods in Romania 2005-2006.

Badea, Alexandru ; Dana, Iulia Florentina ; Moise, Cristian 等

Abstract: The emergency situation caused by the massive floods that affected Romania in 2005 and 2006 led to the activation of the International Charter on Space and Major Disasters. The aim of this study is to design an advanced system for disaster monitoring and management that consists of an operational structure for fast activation of the Charter, processing methodologies for multi-source data (optical and radar satellite images, digital elevation models, topographic maps and other types of ancillary data), creation of a complex GIS (vector and raster data) and generation of spatial maps useful in the assessment of the affected areas.

Key words: emergency situation, International Charter, multi-source data, GIS, spatial maps

1. INTRODUCTION

During the past two years disastrous floods occurred in Central and Eastern Europe and caused extensive damage. Romania was affected by:

* Two series of floods in 2005 (Timis and Siret rivers basins)

* Danube river alluvial plain disaster in 2006

In July 2005, these phenomena had triggered emergency satellite operations under the International Charter on Space and Major Disasters which aims at providing a unified system of space data acquisition and delivery to those affected by natural or man-made disasters through authorized users (source http://www.disasterscharter.org/main_e.html).

The Romanian Government requested the help of the International Charter (Charter Call ID-98) in order to provide as soon as possible useful satellite information. The charter was activated by the European Commission.

2. JULY 2005 FLOODS & CHARTER ACTIVATION

The Romanian Community of experts had to answer in real time at the request of authorities in charge with the crisis management. Based on the first available satellite image--MODIS--the dimension of the disaster could be evaluated.

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The RS/GIS group of the Romanian Space Agency (ROSA) and the Romanian Center for Remote Sensing Apply in Agriculture (CRUTA) started the exchange of information with the French team in charge with this application (CNES and SERTIT Strasbourg RS laboratory).

One of the first images acquired after the activation of the International Charter was a 2.5m resolution SPOT 5 panchromatic image. As an objective document for the evaluation of the crisis situation, a merged color SPOT 5 image was also generated.

The SPOT 5 images have been referenced using a previously orthorectified Landsat ETM image based on dTED1 data. At that moment, regarding the emergency situation, the accuracy of the rectification was considered sufficient for an overview evaluation of the areas covered by water.

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The flooded areas were delineated by visual interpretation using the SPOT 5 panchromatic image (Kainz et al., 2004). The resulting vector was intersected with the FAO-LCCS database (Zeiler, 1999). Thus, the first useful product showing the extent of the affected areas was created.

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The activity of the International Charter on Space and Major Disasters allowed the acquisition of multi-sensor and multi-resolution data (RADARSAT, SPOT 2 & 5), useful in the creation of flood spatial maps (www.rosa.ro).

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A multi-spectral SPOT 2 image and a panchromatic one were also acquired during the crisis. The processing steps were: image geo-referencing, delineation of the interest area, creation of masks for clouds and urban areas, unsupervised and supervised classifications. The results obtained were used forward as input for the atmospheric methods or in post-crisis analysis. As future work, the validation of the algorithms could be done using ground truth data.

3. SPIM PROJECT & OASIS PROGRAM

The floods that affected the Lower Siret Basin in July 2005 represent the event from which the idea of elaborating a research & development project has started. The title of the project is Integrated Pilot System for Monitoring and Determining the Effects of the Floods in the Lower Siret Basin (SPIM) and its main objective is building-up an advanced system for the management of the emergency situations (Agouris & Croituru, 2005).

SPIM participated in the OASIS (Optimizing Access to Spot Infrastructure for Science) program. OASIS is a European program financed by the European Commission. OASIS intends to optimize the access to the SPOT infrastructure so as to facilitate European space scientific research (source http://medias.obs-mip.fr/oasis/).

After the visual interpretation of the images, two types of areas still affected by the 2005 floods have been identified: areas covered by water and areas covered by alluvia.

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The total size of the area affected by floods in July 2005 (the part covered by the SPOT image) was of 15903.85 hectares. For example, approximately 42% of the entire area (6715.14 hectares) was represented by arable land. In 2006, from this area of arable land there were remained almost 4% (reported to the initial affected areas in 2005) still affected by floods (568.68 hectares). The estimated overall percent of areas still affected by floods in 2006 is of approximately 43% comparing to the values from 2005.

4. FLOODS IN 2006

In 2006, the floods affected Romania again in the basin of the Danube River. After the experience acquired in 2005, the Romanian Space Agency decided to take the responsibility to fully process the satellite data provided by the designated coordinator of this new Charter Call ID-121 (DLR). The multisensor satellite data used during the crisis derived from RADARSAT, SPOT 4 and SPOT 5, FORMOSAT 2, Landsat ETM, ERS 2, ENVISAT, DMC, IRS and SRTM.

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5. CONCLUSIONS

In managing the emergency situations, the necessity to take into account the quality of the available basic data (DTM, datum parameters, etc) is compulsory. Also, the field information is essential. These "against the clock" GMES applications demonstrated the usefulness of the International Charter on Space and Major Disasters (Badea, 2006). The high and very high resolution SPOT images obtained during (International Charter) and after the crisis (OASIS program) were extremely useful for post crisis evaluation of the areas affected by floods (one year after).

6. REFERENCES

Agouris, P. & Croituru, A. (2005): Next Generation Geospatial Information--From Digital Image Analysis to SpatioTemporal Databases, Routledge, ISBN 0415380499, UK

Badea, A. (2006): Support Activities for Monitoring of Floods in the Danube River Basin, XIIIth ESRI Conference, Bucharest

Dana, I. (2007): Integrated Pilot System for Monitoring and Determining the Effects of the Floods in the Lower Siret Basin (SPIM), 1st SPOTDAY Conference, Bucharest

ESRI. 1992. Map Projections & Coordinate Management: Concepts and Procedures. Redlands, California: ESRI, Inc.

Kainz, W.; Li, Z. & Zhou, Q. (2004): Advances in Spatial Analysis and Decision Making, Swets & Zeitlinger, ISBN 90 5809 652 1, Lisse, Netherlands

Zeiler, M. (1999): Modeling Our World--The ESRI Guide to Geodatabase Design, Environmental Systems Research Institute, Inc., ISBN 1-879102-62-5, Redlands, California http://portal.rosa.ro/index.php?category_id=1&history=2005htm

Table 1. Evaluation of the affected areas (2005 & 2006)

 Area Percent Area Percent
 (ha) (%) (ha) (%)
 2005 2005 2006 2006

Arable land 6715.14 42.22 568.68 3.58
Grassland 3456.55 21.73 2694.21 16.94
Vineyards & orchards 298.86 1.88 9.58 0.06
Built-up areas 1163.81 7.32 162.65 1.02
Forest/riverside 1994.81 12.54 1181.15 7.43
Waters 791.66 4.98 781.86 4.92
Non-productive terrain 1483.03 9.32 1453.29 9.14
 TOTAL 15903.85 100.00 6851.41 43.08