INNOVATIONS IN REMOTE SENSING AND PHOTOGRAMMETRY
CONTENTS METHODS TECHNIQUES AND SENSORS FOR PRECISION FLOOD MONITORING THROUGH REMOTE SENSING 1 REMOTE SENSING AS A TOOL FOR ANALYSING CHANNEL DYNAMICS AND GEOMORPHIC EFFECTS OF FLOODS 27 THE USE OF DEM BASED APPROACHES TO DERIVE A PRIORI INFORMATION ON FLOOD PRONE AREAS 61 RIVER FLOOD FORECASTING SYSTEM AN INTERDISCIPLINARY APPROACH 81 MONITORING FLOOD EXTENT AND AREA THROUGH MULTISENSOR MULTI TEMPORAL REMOTE SENSING THE STRYMONAS GREECE RIVER FLOOD 101 ADAPTIVE SAR IMAGE PROCESSING TECHNIQUES TO SUPPORT FLOOD MONITORING FROM EARTH OBSERVATION DATA 115 FLOOD MAPPING IN VEGETATED AND URBAN AREAS AND OTHER CHALLENGES MODELS AND METHODS 135 DATA FUSION THROUGH BAYESIAN METHODS FOR FLOOD MONITORING FROM REMOTELY SENSED DATA 181 METHODS TECHNIQUES AND SENSORS FOR PRECISION FLOOD MONITORING THROUGH REMOTE SENSING ABSTRACT IN THIS CHAPTER WE INTRODUCE THE SUBJECT MATTER OF THE BOOK HIGHLIGHTING THE MANY ASPECTS OF SIGNAL AND IMAGE PROCESSING MODELLING AND INTERPRETATION INVOLVED IN THE PRODUCTION OF HIGH PRECISION OOD MAPS FROM REMOTELY SENSED DATA FOR EACH ELD LINKED TO THE OOD MAPPING ACTIVITY WE SUMMARIZE SOME BASIC DE NITIONS AND RESEARCH ASPECTS REVIEWING BRIE Y SOME OF THE MOST RECENT APPLICATIONS AND CITING APPROPRIATE LITERATURE WE THEN INTRODUCE ORGANICALLY THE SUBJECTS TREATED IN EACH OF THE FOLLOWING CHAPTERS KEYWORDS FLOOD MONITORING OPTICAL AND SAR REMOTELY SENSED DATA AUTOMATIC OOD DETECTION TECHNIQUES GEOMORPHOLOGICAL MAPPING 1 INTRODUCTION CLIMATE CHANGE AND ANTHROPOGENIC PRESSURE ARE INCREASING FREQUENCY AND INTENSITY OF OOD PHENOMENA IN MANY COUNTRIES THIS CAUSES INCREASING DAMAGES AND THREATS TO LIFE PROPERTY AND CULTURAL HERITAGE COUNTERMEASURES AND PREPAREDNESS DIRECTIVES ARE BEING TAKEN AT LOCAL UP TO CONTINENTAL LEVEL 1 71 88 SEVERAL ENVIRONMENTAL AGENCIES AROUND THE WORLD SUPPORT COMMUNITIES IN PROTECTING LIVES AND PROPERTY BY PROVIDING TOOLS AND INFORMATION TO HELP THEM UNDERSTAND LOCAL OOD RISK AND MAKE COST EFFECTIVE MITIGATION DECISIONS SUCH INFORMATION IS USUALLY PROVIDED IN THE FORM OF MAPS IN PARTICULAR OOD INUNDATION MAPS ARE USED MAINLY FOR FORECAST SCENARIOS MITIGATION AND PLANNING OOD RISK ANALYSES TIMELY RESPONSE 1 DAMAGE ASSESSMENT ENVIRONMENTAL AND ECOLOGICAL ASSESSMENTS THESE MAPS ARE TRADITIONALLY CREATED USING HYDRAULIC AND TOPOGRAPHIC MODELLING TO SIMULATE AND VISUALIZE A WIDE RANGE OF OODING SCENARIOS HOWEVER THE METHODS FOR ESTIMATION OF OOD RISK MAPS BASED ON INUNDATION MODELS AND STATISTICS ARE SOMETIMES NOT VERY ACCURATE BECAUSE OF THE LARGE UNCERTAINTIES IN LAND SURFACE TOPOGRAPHY HYDROLOGICAL MODELLING AND STATISTICS 4 FURTHERMORE THE CONTROLLING RISK FACTORS CHANGE GEOGRAPHICALLY AND TEMPORALLY AND AN UNDERSTANDING OF THEIR PHYSICAL AND SPATIOTEMPORAL CHARACTERISTICS IS ESSENTIAL FOR THE PROJECTION OF FUTURE OOD RISKS AND THE DEVELOPMENT OF EFFECTIVE OOD MITIGATION MEASURES 109 REMOTE SENSING PLAYS AN IMPORTANT ROLE IN ALL THE PHASES OF HAZARD MANAGEMENT FROM THE ALERT AND PREPAREDNESS PHASE TO THE EMERGENCY MANAGEMENT AND CIVIL PROTECTION AND UP TO DAMAGE ASSESSMENT FOR RISK REDUCTION RESEARCH AND OPERATIONAL ACTIVITIES IN THE ELD OF OOD MONITORING AND PREVENTION BENE T FROM AVAILABILITY OF BOTH OPTICAL AND RADAR REMOTELY SENSED RS DATA RS DATA OFFER SOME LONG RECOGNIZED ADVANTAGES SUCH AS THE CAPABILITY OF PROVIDING SYNOPTIC INFORMATION OVER WIDE AREAS AT LOW COSTS THE RELIABILITY OF DATA ACQUISITION SCHEDULE THE IMMUNITY TO LOCAL HINDRANCES SUCH AS SITE ACCESSIBILITY OR DANGEROUS ENVIRONMENTAL CONDITIONS ETC RS DATA AVAILABILITY HAS INCREASED OVER THE PAST FEW YEARS THANKS TO RENEWED EFFORTS BY SEVERAL NATIONAL SPACE AGENCIES IN DEVELOPING AND OPERATING REMOTE SENSORS WITH CHARACTERISTICS 1 2 ORDERS OF MAGNITUDE BETTER THAN THOSE RELATED TO THE LEGACY GENERATION AS A RESULT SUCH NEW GENERATION DATA GIVE MORE OPPORTUNITIES OF USE AND ALLOW NEW APPLICATIONS OFTEN OPENING NEW RESEARCH ELDS IN THE CASE OF OOD MONITORING HIGH RESOLUTION MULTI TEMPORAL DATA GIVE THE CHANCE TO IMPROVE SIGNI CANTLY THE PERFORMANCES OF FORECAST ALERT AND POST EVENT MONITORING OF INUNDATION EVENTS HOWEVER AS IS OFTEN THE CASE NEW OPPORTUNITIES AND APPLICATIONS POSE NEW CHALLENGES THE NATURE OF THE DATA THE DIFFERENT SIZE AND SCALE OF THE OBJECTS AND THE PROCESSES WHICH CAN BE NOW INVESTIGATED EVEN THE SHEER QUANTITY OF AVAILABLE DATA ALL REQUIRE NEW OR MORE POWERFUL TOOLS TO BE SUITABLY DEALT WITH IN THE PARTICULAR ELD WHICH IS THE SUBJECT OF THIS BOOK DEVISING RELIABLE AND ROBUST METHODS TO EXPLOIT REMOTELY SENSED DATA TO THEIR FULL POTENTIAL INVOLVES RECURRING TO A LARGE SPECTRUM OF ELDS OF EXPERTISE AND KNOWLEDGE WHICH ARE NOT ALL USUALLY AVAILABLE TO SINGLE SCIENTISTS OR RESEARCH GROUPS IN THE PRESENT INTRODUCTION WE PROPOSE A SHORT REVIEW OF THE MAIN ASPECTS LINKED TO LAST GENERATION REMOTE SENSING DATA ANALYSIS AS APPLIED TO OOD MONITORING BY BRIE Y ILLUSTRATING THE LINKS TO RESEARCH ELDS AND THEORETICAL BACKGROUNDS AS CAN BE FOUND AT THE PRESENT TIME INNOVATIONS IN REMOTE SENSING AND PHOTOGRAMMETRY 2 2 OVERVIEW OF FLOOD MONITORING SYSTEMS AND REMOTE SENSING APPROACHES FLOODS ARE BROADLY DE NED AS EVENTS IN WHICH WATER COVERS LAND AREAS WHICH ARE NOT NORMALLY COVERED BY WATER 28 THIS DE NITION COVERS A WIDE VARIETY OF EVENTS UNDER THE GEOMORPHIC FRAMEWORK AS REGARDS SIZE DURATION OR CAUSE CONSIDER FOR INSTANCE THE EXTREMES OF RECURRENT OODS CAUSED BY LARGE RIVERS WHICH CAN COVER THOUSANDS OF HECTARES AND ASH OODS TYPICALLY AFFECTING SMALL AREAS IN A SHORT TIME BUT WITH POTENTIALLY DESTRUCTIVE EFFECTS LINKED TO THE NOMENCLATURE CONNECTED TO OOD EVENTS IS THEIR MANAGEMENT WHICH INCLUDES MONITORING AS A MEASURE TO REDUCE DAMAGES CONNECTED TO EVENTS FLOOD MONITORING ACTIVITIES CAN BE ROUGHLY DIVIDED INTO THREE BROAD SETS ACCORDING TO THE STAGE OF OPERATIONS WITH RESPECT TO THE EVENT OCCURRENCE 95 1 FORECASTS 2 EMERGENCY MONITORING 3 DAMAGE ASSESSMENT IN SPITE OF THIS PERHAPS SOMEWHAT ARTI CIAL SEPARATION IN TIME THE THREE KINDS OF ACTIVITY ARE ACTUALLY CLOSELY INTERTWINED FOR INSTANCE EFFECTIVE FORECASTS HELP DIRECT ING EMERGENCY MONITORING EFFORTS TO THE MOST AFFECTED AREAS AND INFRASTRUCTURES ALSO PRECISE DAMAGE ASSESSMENT CAN BE USED AS BENCHMARK TO IMPROVE THE FORECAST CAPABILITIES OF CURRENT SYSTEMS THE ABOVE SUBDIVISION DETERMINES THE TYPE OF RS APPROACHES AND DATA USED IN EACH ACTIVITY FORECASTS INVOLVE MAINLY METEOROLOGICAL INFORMATION SO LOW TO MEDIUM RESOLUTION OPTICAL DATA ARE USUALLY INVOLVED IN EMERGENCY MONITORING THE EMPHASIS IS CLEARLY ON FAST RESPONSE AND RELATIVELY HIGH RESOLUTION SO A POTENTIALLY WIDE VARIETY OF SENSORS CAN BE INVOLVED WORKING IN BOTH THE OPTICAL AND MICROWAVE SPECTRAL REGIONS HOWEVER THE TYPICAL BAD WEATHER CONDITIONS ASSOCIATED TO OOD EVENTS WITH THICK CLOUD COVERAGE PRESENT AT LEAST DURING THE INITIAL SURGES MAKE PARTICULARLY ATTRACTIVE DATA FROM IMAGING RADARS WITH RESPECT TO OPTICAL SENSORS SYNTHETIC APERTURE RADARS ARE MOSTLY INSENSITIVE TO CLOUD COVER AND ALSO TO SUN ILLUMINATION THE THIRD TYPE OF APPLICATION IS THE ONE WHICH INVOLVES THE MOST ADVANCED PROCESSING TECHNIQUES REMOTE SENSING CAN PLAY HERE A KEY ROLE IN DE NING THE SPATIAL AND TEMPORAL CHANGES OF FACTORS WHICH IN RETURN CONTROL OOD GENERATION AND RISK FOR INSTANCE DATA AND ALGORITHMS ARE VERY PROMISING IN DE NING TWO SELDOM DE NED FEATURES OF OODING ONE IS THE SPATIOTEMPORAL EVOLUTION OF THE OOD THIS OFTEN RELIES MAINLY ON EYEWITNESS ACCOUNTS ESPECIALLY WHERE NO STREAM GAUGE MEASUREMENTS ARE AVAILABLE ACCOUNTS FROM EYEWITNESSES ARE OCCASIONALLY CITED IN ASH OOD STUDIES AND THEY HAVE SELDOM BEEN TO OUR KNOWLEDGE SYSTEMATICALLY COLLECTED AND ANALYSED MULTI TEMPORAL AND MULTISENSOR DATA ALLOW A TEMPORAL AND SPATIAL RECONSTRUCTION OF OOD INUNDATION FROM THE BEGINNING UNTIL THE END WHEN ALL THE INUNDATED AREAS RETURN DRY THE SECOND IS RELATED TO THE SEDIMENT TRANSFER PROCESSES AS FOR EXAMPLE EROSION AND DEPOSITION ON SLOPES AND IN RIVER BEDS HYPERCONCENTRATED MUD DEBRIS OWS ETC EROSION AND SEDIMENTARY FEATURES MAINLY FOCUS ON THE POST OOD INVESTIGATION AND INNOVATIONS IN REMOTE SENSING AND PHOTOGRAMMETRY 3