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Crop Type Determination
Different crops have unique roughness and moisture levels. Radar is
sensitive to differences in these parameters resulting in contrasting
backscatter.
RADARSAT beam mode
- The size of the agricultural field being imaged
should be taken into consideration when choosing a beam mode. Ideally, the
beam mode resolution should be several times smaller than the size of the
agricultural fields (i.e.,Fine or Standard beam mode).
RADARSAT incidence angle
- The main parameter differentiating crop
type is geometric structure of individual plants ; shallow incidence angles
maximize the contrast in backscatter resulting from differences in structure.
Look direction
- A look direction perpendicular to row direction
maximizes backscatter from the crop canopy. An ascending (18:00 H local time)
pass may be preferred to minimize the presence of dew which may decrease
interpretation and classification accuracy. Conversely, the descending pass
(06:00 H local time) may reduce the effects of rain events in areas of
convection related rainfall.
When to acquire RADARSAT data
- Acquire data when differences in plant
geometric structure between different crop types are maximized. Crop type
determination significantly improves through the use of temporal radar data
acquired at different growth stages.
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