The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008
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—Sukhothai
■-*— Phrae
Uttaradit
Phitsanulok
—*■ ■ Phichit
Nakhon Sawan
—=_... Uthai Thani
/ ^ Z' / / /
Figure 7. Major rice harvested areas for each province in the
Northern part of Central Plain of Thailand (by FAOSTAT)
2.3.2. Geomorphological survey map (Ohkura,1989) and
satellite data
The entire Chao Phraya river basin between Nakhon Sawan and
Bangkok metropolis often suffer from flood at the end period of
every rainy season. The rainy season usually begins in about
May and it will end in about October. Figure 8. shows such
kind PALSAR image and the result of mathematical
morphology applied to the left image.
Figure 8. PALSAR image in the entire Chao Phraya river on
October 12 th , 2006 (left) and the result of morphological
analysis (right, white color)
The author superimposed the result of morphological analysis
as the flood possibility areas over the geo-morphological
survey map (Figure 9). Though the surface land use is changed
by farm land consolidation, the possibility flood areas agree
with back marsh and delta category avoiding natural levees.
The geo-morphological survey map represents the
micro-topography and it reflects the process of formation of
geographical features. As the flood time is the sediment
procedure, the flood inundated areas should coincide with the
geo-morphological survey map, even if the surface land use
was changed. Therefore this kind of micro-topography map can
be used for the flood hazard map.
Figure 9. Geomorphological survey map (right) and the
superimposed flood possible areas calculated by mathematical
morphology operation from PALSAR image (left; red color)
3. HOW TO MAKE “FDMS”
It is very important that the results of flood extent estimation
are handed to the people concerning to disaster aid or reduction.
Therefore many kinds of global platform for disaster risk
reduction on the Internet are proposed. The author converted
the result of this Thailand flood analysis into KML format files
and superimposed those files on the “Google earth” (Figure 10,
11). The KML is similar to the international Geospatial
Information System standard, GML (Geography markup
language) of OGC (Open Geospatial Consortium) or IS019136.
And The GML is a kind of data format for G1S data exchange
and distribution using the Internet web, what we call,
“GeoWeb” (Lake, 2004) . If every organization related to the
disaster reduction adopts GML or KML, such kind of
international standard data format, those organization’s work in
close cooperation with publishing its disaster information on
the line in the near future. Furthermore Semantic Web will
strengthen such kind “Geospatial Web” (Scharl, 2007). Those
data standards can apply to the future disaster management
system (FDMS).
Figure 10. Google earth browser image and geo-morphological
survey map on it