mapping and monitoring rice areas using multisensor multitemporal synthetic aperture radar (sar)...
TRANSCRIPT
In the Philippines, rice is cultivated on 2.76 million ha, much of which is cropped
twice a year. However, production is not enough to meet increasing domestic
demand. In support of the country's rice self-sufficiency plan, IRRI and PhilRice
formed an integrated project funded by the Department of Agriculture. Part of this
project is the mapping and assessment of rice areas in the country. In partnership
with sarmap, a Swiss company, we are developing a dedicated processing chain
that enables the mapping of rice areas, detection of emergence, and monitoring of
growth for the whole season. This poster presents the processing chain and the
first rice mapping results from this public/private research partnership.
• We are using multitemporal remote sensing images acquired by different SAR
sensors to adequately capture flooding, planting, and emergence dates in major
rice-producing provinces of the Philippines (Table 1, Fig. 1).
Mapping and monitoring of rice
areas
Table 1. Description of SAR data used.
Sensor Ban
d
Wavelengt
h (cm)
Spatial
resolution (m)
Revisit
period (d)
Polarizationa
Cosmo SkyMed (CSK)
ENVISAT ASAR
ALOS-PALSAR
X
C
L
3.0
5.6
23.6
3 to 15
15 to 25
8 to 15
4
35
46
HH
HH
HH-HH/HV
Conclusions and further work
• Multitemporal and multisensor acquisitions are required to properly capture, at the
country level, the critical stages, such as flooding and planting dates, that vary
widely in time and space.Fig. 2. General procedure for rice mapping in RICEscape®.
• We are working to further improve the rice mapping methodology. Rice ecologies
vary across the Philippines and the methodology must accommodate this
variation.
aHH = radar signal is emitted and received in the horizontal plane, HV = radar signal is emitted in
the horizontal plane and received in the vertical plane.
• When completed, this project will provide the first SAR-based high-spatial-
resolution map of rice areas covering the major rice-producing provinces in the
Philippines.
• With the launch of Sentinel-1A and 1B (ESA C-band missions) planned for 2012-
13, the temporal acquisition frequency (revisiting cycle, 7 days) will enable
continuous rice growth monitoring at the country level. C-band data from Sentinel
will also be provided free of charge.
DEM
Multilooking + filtering
Geometric calibration
Radiometric calibration
Radiometric normalization
Filtering
SAR-derived rice map
Preprocessing
Classification
• sarmap has developed a dedicated rice mapping software, RICEscape®, to
automate SAR data preprocessing while still allowing operators to fine-tune the
mapping process based on their location-specific knowledge of rice ecologies
(Fig. 2).
• Planting dates vary widely across the Philippines, highlighting the importance of
acquiring multitemporal images for monitoring rice areas.
• Flooding, planting, and crop emergence (Fig. 3) can be detected using multi-
temporal SAR images and used to map rice areas (Fig. 4).
Preliminary findings
Fig. 4. Preliminary rice map derived from multitemporal CSK and
PALSAR images over Nueva Ecija.
Information that will be generated from this project is crucial in rice importation
decisions and in prioritizing research and extension activities such as the
dissemination of location-specific technologies.
Fig. 1. The top 20 rice-growing provinces (yellow) and monitoring sites (red dots) (A), and
coverage of acquired SAR images (B, C, D) for the 2011 dry season.
PALSAR
D A
ASAR
C
Rice map
generation
Mask
generation
Preprocessed SAR image
Validation using ground
truth data
Fig. 6. Comparison of BSWM 1980 (A), SAR-derived 2011 dry season only (B), and MODIS-
derived 2009 (C) rice maps highlighting the changes in rice areas (A vs. B, C) and difference in
resolution (B vs. C).
• Planting dates can be mapped using SAR temporal signatures (Fig. 5).
15 Dec. 2010
31 Jan. 2011
23 March
2011
Standard format original
SAR products
(Digital elevation model)
Fig. 3. Actual condition
during field visits.
1International Rice Research Institute, Los Baños, Laguna, Philippines, 2Philippine Rice Research Institute, Science City of Muñoz, Nueva Ecija, Philippines, 3sarmap, Cascine di Barico, CH 6989 Purasca, Switzerland
Jeny Raviz,1 Eduardo Jimmy Quilang,2 Massimo Barbieri,3 Elmer Alosnos,2 Sonia Asilo,1 Gina Balleras,2 Airene Claire Baradas,2 Artemio Corpuz,2 Jovino de Dios,2 Rona Dollentas,2
Eddie Dupitas,2 Noel Ganotisi,2 Francesco Holecz,3 Alice Laborte,1 Mary Rose Mabalay,2 Juanito Maloom,2 Aileen Maunahan,1 Jean Rochelle Mirandilla,2 Andrew Nelson,1 Arnel
Rala,1 Gilbert Romarez,2 Albert Christian Suñer,2 Belen Tabudlong,2 Frenciso Varquez,2 and Joana Rose Vergara2
0
20
40
60
80
100
1 Dec 2010 28 Dec 2010 18 Jan 2011 31 Jan 2011 1 Mar 2011 23 Mar 2011
Plant height (cm)
–15
–14
–13
–12
–11
–10
–9
–8
Backscatter (dB)Planting
Tillering
Milking
Harvest
Plant height, cm
Backscatter,
dB
Fig. 5. Temporal signature of rice derived from multitemporal images and rice growth stage based
on actual field observations in Nueva Ecija.
• The rice area detected with RICEscape® compares favorably with the rice area
depicted in the Bureau of Soils and Water Management (BSWM) and Moderate
Resolution Imaging Spectroradiometer (MODIS) rice maps (Fig. 6).
Area (000 ha) 46.0 38.1 59.3
A B C
CSK
B
4 Jan. 2011
Mapping and monitoring rice areas using multisensor Mapping and monitoring rice areas using multisensor Mapping and monitoring rice areas using multisensor Mapping and monitoring rice areas using multisensor
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