Namibia PDNA 2009 - GFDRR

Relevant satellite data may be procured directly from commercial
data vendors or provided under the so-called International
Charter “Space and Major Disasters”, a voluntary arrangement
amongst international space agencies to make their data assets
available in case of disasters. The latter was triggered by the
Government for the flooding events in northern Namibia (both
in 2008 and 2009). Given the nature of the event, and prevailing
weather conditions, a number of SAR data sets were procured
(from the Canadian Radarsat and German TerraSAR-X sensors,
respectively). These were processed into flood extent maps by
service entities like UNOSAT and the mapping department of the
German Aerospace Center (ZKI-DLR). High resolution SPOT-5
VNIR imagery was also used to generate flood extent samples
around the major municipal areas. Publicly accessible copies with
relevant metadata were made available to the PDNA team. A
special request was made to ZKI-DLR for digital vector outlines
of detected flood extent, for comparison to relevant GIS data
sets that could be compiled in Namibia. JRC purchased further
satellite data for field mission preparation and flood extent
estimation (in particular a QuickBird very high resolution image
of early April 2009 around Oshakati and a Formosat coverage of
the Caprivi area). Flood maps and geo-referenced imagery were
prepared as KML SuperOverlays to integrate easily into Google
Earth.
Figure 45: The UNOSAT flood extent map of a part of the Osumati region, derived from an ENVISAT ASAR image of 19
March 2009, provided under the International Charter “Space and Major Disasters” by the European Space Agency.
Figure 46: The DLR flood extent vector map
Figure 46 presents an example of a
DLR flood extent vector map (light
blue), derived from a Radarsat-1 SAR
image of 6 March 2009, provided
under the International Charter “Space
and Major Disasters” by the Canadian
Space Agency. The flood vector is
overlaid with the data in figure 46 to
highlight its use in further fine-tuning
the DaLA field survey planning. Note
that some of the school locations are
covered by the flood extent vector,
hence, are most likely candidates for
an in-situ visit.
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