Space Technology and Geographic Information Systems Applications in adb projects

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Contribution of Space Technology 
First, paddy fields are detected and mapped 
using satellite radar data from multiple seasons. 
Because radar’s active radio signal penetrates 
clouds, it is useful for obtaining data in regions with 
frequent cloud coverage during the rainy season. 
Before rice is planted, the surface of the rice field 
reflects the radar signal back like a mirror, and no 
signals returns to the sensor. In this situation, the 
radar imagery looks relatively dark. Once the rice 
begins to grow, however, the radar imagery looks 
relatively bright because the signal is scattered 
by the rice plants and returns to the sensors. By 
superimposing images taken before planting and 
after growth, cultivated areas of rice fields can be 
determined based on where the brightness of the 
signal has changed. Figure 3 shows Radar Signal 
Reflection for rice growth.
Optical satellite imagery with higher resolution is used for validation of the paddy rice cultivation 
area maps that have been developed using radar satellite data. By integrating information about 
rice production per unit obtained from sample crop cuttings and other statistical information with 
the cultivation area maps, rice crop production information is obtained. In order to make the system 
operate in a sustainable manner, this system applies satellite radar data in Scan Synthetic Aperture 
Radar (SAR) mode with relatively low spatial resolution based on a 100 m grid and wider coverage. The 
target rice crop production estimation is at the provincial level.
Results
This technical assistance project is ongoing and the results of these applications in pilot provinces in 
each country will be available by the end of the project, which is planned for May 2015. 
Figure 3 Radar Signal Reflection
Source: Japan Aerospace Exploration Agency.