Effect of sugarcane-planting row directions on ALOS/PALSAR satellite images

Figures & data

Table 1. Characteristics of ALOS/PALSAR images analyzed in this research

Overpass	Acquisition mode	Number of looks
19 February 2007	FBS	2
22 August 2007	FBD	4
7 October 2007	FBD	4
22 February 2008	FBS	2
8 April 2008	FBS	2
24 May 2008	FBD	4
24 August 2008	FBD	4
9 October 2008	FBD	4
24 February 2009	FBS	2
27 August 2009	FBD	4
Note: FBS = fine beam single mode, FBD = fine beam dual mode.

Table 2. Calibration factors of PALSAR images

Acquisition mode	Up to 8 January 2009 (dB)	After 9 January 2009 (dB)
FBS HH	−83.4	−83.0
FBD HH	−83.2	−83.0
FBD HV	−80.2	−83.0
Source: AUIG (2009).

Figure 1. Diagram used to classify sugarcane plots into parallel and perpendicular to the sensor's look direction.

Figure 2. Average spaces between sugarcane planting rows (a) and between plants in the same row (b).

Figure 3. Mean σ° from the sugarcane plots, and rainfall data from the study area.Note: M – month.

Table 3. A Mann–Whitney test was used to compare sugarcane's plots parallel and perpendicular to the satellite's look direction (α = 0.05) and the descriptive summary statistics (mean and standard deviation)

Satellite overpass	Polarization	Age of plant (months)	Parallel plots (µ and σ)	Perpendicular plots (µ and σ)	P-value
19 February 2007	HH	3	−11.56 (σ = 0.62)	−9.29 (σ = 0.56)	0.0002
22 August 2007	HH	9	−12.83 (σ = 0.66)	−12.48 (σ = 0.92)	0.5966 ^a
22 August 2007	HV	9	−15.45 (σ = 0.96)	−15.78 (σ = 1.54)	0.2121 ^a
7 October 2007	HH	11	−15.78 (σ = 1.02)	−15.11 (σ = 1.44)	0.3847 ^a
7 October 2007	HV	11	−17.49 (σ = 1.25)	−17.66 (σ = 1.95)	0.3256 ^a
22 February 2008	HH	2	−11.15 (σ = 1.18)	−8.91 (σ = 0.91)	0.0013
8 April 2008	HH	4	−11.16 (σ = 0.59)	−9.10 (σ = 0.68)	0.0002
24 May 2008	HH	5	−12.26 (σ = 0.66)	−11.51 (σ = 0.58)	0.0376
24 May 2008	HV	5	−16.57 (σ = 0.87)	−15.94 (σ = 0.86)	0.1121 ^a
24 August 2008	HH	8	−13.52 (σ = 0.53)	−12.30 (σ = 0.73)	0.0028
24 August 2008	HV	8	−16.72 (σ = 0.72)	−16.22 (σ = 0.98)	0.2413 ^a
9 October 2008	HH	10	−10.46 (σ = 0.54)	−9.77 (σ = 0.50)	0.0091
9 October 2008	HV	10	−12.46 (σ = 0.97)	−12.80 (σ = 0.76)	0.3913 ^a
24 February 2009	HH	2	−14.56 (σ = 0.40)	−13.50 (σ = 0.63)	0.0039
27 August 2009	HH	8	−11.02 (σ = 0.55)	−10.32 (σ = 0.40)	0.0145
27 August 2009	HV	8	−15.42 (σ = 0.98)	−15.87 (σ = 0.72)	0.5636 ^a
Note: ^a Not significant at 5%.

Figure 4. PALSAR HH-polarized image from 22 February 2008 (a), QuickBird optical image available in the Google Earth^TM program from April 2008 (b) and a PALSAR HH-polarized image from 8 April 2008, (c) overpasses. Parallel plots are outlined in red, and perpendicular plots are outlined in green. The image scene is 2.9 km.

Figure 5. Panoramic field photo obtained on 14 May 2010, illustrating a typical directional terrain roughness found in the study area after sugarcane harvesting.

Silva , W. F. , Rudorff , B. F. T. , Formaggio , A. , Paradella , W. R. and Mura , J. 2009 . Discrimination of Agricultural Crops in a Tropical Semi-Arid Region of Brazil based on L-Band Polarimetric Airborne SAR Data . ISPRS Journal of Photogrammetry and Remote Sensing , 64 ( 5 ) : 458 – 463 .

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