Geography Reference
In-Depth Information
Emergency management
Floodplain mapping
Insurance assessment
0
20
40 60
Spatial resolution (m)
(a)
80
100
Operational flood warning, forecasting
Rescue, evacuation, emergency management
Supply of food and medical aid
Repair of flood defences, infrastructure
Mapping for hydrological modelling,
agricultural damage, insurance assessment
0
5
10
15
20
25
30
Time (days)
(b)
Figure 6.3
(a) Maximum acceptable resolution range of satellite data for different flood requirements. (b) Desirable turnaround time
for acquisition, processing and dissemination of satellite data for flood requirements (Modified from Blyth, 1997).
to a flood event would be reduced to a few hours (Ip
et al., 2006). The objective of such an experiment would
be to demonstrate the ability of an autonomously con-
trolled spacecraft to detect and react to dynamic events
such as floods while optimising use of limited downlink
bandwidth and maximising science return. However, to
date, algorithms that enable an automatic delineation of
flooded areas have not been developed to a level where
they could be used operationally; although it is undeniable
that they are an essential component of any SAR based
monitoring service (Matgen, 2011). What is needed at
this stage is the development of new concepts for an effi-
cient and standardised SAR based monitoring of floods.
In this context, Matgen et al. (2011) propose a hybrid
methodology, which combines radiometric threshold-
ing and region growing as an approach enabling the
automatic, objective and reliable flood extent extraction
from SAR images. First results indicate that the proposed
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