The impact of seasonality on multi-scale feature extraction techniques

Figures & data

Figure 1. Example of seasonal differences for Charlotte, North Carolina (United States) imagery. (a) Charlotte 01/24/2016 (Winter Season) and (b) Charlotte 07/05/2016 (Summer Season).

Figure 2. Example of seasonal differences for Kano, Nigeria imagery. (a) Kano 01/27/2014 (Dry Season) and (b) Kano 08/29/2014 (Wet Season).

Table 1. Imagery collection parameters.

Study Area	Month	Day	Year	Season	Sensor	Cell size
Charlotte	January	24	2016	Winter	WV02	4.5e−06, 4.5e−06
Charlotte	April	04	2016	Spring	WV02	4.5e−06, 4.5e−06
Charlotte	July	05	2016	Summer	WV02	4.5e−06, 4.5e−06
Charlotte	October	10	2016	Fall	WV02	4.5e−06, 4.5e−06
Kano	January	27	2014	Dry	WV02	4.5e−06, 4.5e−06
Kano	May	02	2014	Midpoint	WV02	4.5e−06, 4.5e−06
Kano	August	29	2014	Wet	WV02	4.5e−06, 4.5e−06
Kano	November	26	2014	Midpoint	WV03	3.6e−06, 3.6e−06

Figure 3. Charlotte and Kano training blocks along with reference data (building features).

Figure 4. Example of feature extraction during model creation for Charlotte 07/05/2016 image. (a) Isolated area downtown and (b) HOGGLCM extracted features for the area.

Figure 5. Charlotte January feature run example.

Table 2. Significance of comprehensive differences.

Study area	Factor	Metric	p-Value
Charlotte	Seasons	Precision	0.00
Charlotte	Seasons	Recall	0.00
Charlotte	Seasons	F1 Score	0.00
Kano	Seasons	Precision	0.51
Kano	Seasons	Recall	0.02
Kano	Seasons	F1 Score	0.51
Charlotte	Features	Precision	0.00
Charlotte	Features	Recall	0.00
Charlotte	Features	F1 Score	0.00
Kano	Features	Precision	0.00
Kano	Features	Recall	0.00
Kano	Features	F1 Score	0.00

Table 3. Significance of individual differences.

Study area	Feature	Metric	p-Value
Charlotte	HOGGLCM	Precision	0.00
Charlotte	HOGGLCM	Recall	0.00
Charlotte	HOGGLCM	F1 Score	0.00
Charlotte	TEXTONS	Precision	0.00
Charlotte	TEXTONS	Recall	0.48
Charlotte	TEXTONS	F1 Score	0.00
Charlotte	VEGIND	Precision	0.00
Charlotte	VEGIND	Recall	0.00
Charlotte	VEGIND	F1 Score	0.00
Kano	HOGGLCM	Precision	0.43
Kano	HOGGLCM	Recall	0.20
Kano	HOGGLCM	F1 Score	0.41
Kano	TEXTONS	Precision	0.16
Kano	TEXTONS	Recall	0.50
Kano	TEXTONS	F1 Score	0.16
Kano	VEGIND	Precision	0.46
Kano	VEGIND	Recall	0.00
Kano	VEGIND	F1 Score	0.47

Figure 7. F1 score differences for seasons. (a) Charlotte F1 scores for seasons and (b) Kano F1 scores for seasons.

Figure 8. F1 score differences for features. (a) Charlotte F1 scores for features and (b) Kano F1 scores for features.

Figure 6. Example of VEGIND results. (a) Charlotte 07/05/2016 Run Number 14 and (b) Kano 08/29/2014 Run Number 9.

Figure 9. Seasonal impact on each feature. (a) Charlotte F1 score mean by season and (b) Kano F1 score mean by season.

Table A1. VEGIND feature.

Spectral indices
EVI2
NDVI
TNDVI
SAVI
GNDVI
NDBI
NDWI
MNDWI
MSAVI2
YNDVI
ENDVI
pNDVI
rbNDVI
gbNDVI

Table A2. Metric results for Charlotte (SD is standard deviation).

Metric	Month	HOG mean	TXT mean	VEG mean	HOG SD	TXT SD	VEG SD
Precision	January	12.32	13.02	12.77	0.59	0.52	0.72
Precision	April	11.50	11.94	13.14	1.18	0.72	0.67
Precision	July	10.07	11.69	13.57	0.72	0.55	0.52
Precision	October	9.83	11.25	11.99	0.53	0.61	0.38
Recall	January	96.62	95.77	97.00	1.48	0.98	1.13
Recall	April	97.56	94.58	97.48	1.59	2.55	1.02
Recall	July	98.45	94.99	98.11	1.68	2.17	1.25
Recall	October	98.73	94.65	98.12	1.91	2.57	0.83
F1 Score	January	21.85	22.91	22.56	0.90	0.79	1.11
F1 Score	April	20.56	21.19	23.15	1.85	1.07	1.02
F1 Score	July	18.25	20.81	23.84	1.14	0.84	0.80
F1 Score	October	17.87	20.09	21.37	0.83	0.92	0.59

Table A3. Metric results for Kano (SD is standard deviation).

Metric	Month	HOG mean	TXT mean	VEG mean	HOG SD	TXT SD	VEG SD
Precision	January	25.55	24.00	28.36	3.10	1.62	2.61
Precision	May	25.24	25.12	29.37	3.48	2.04	2.79
Precision	August	24.83	24.71	29.26	2.92	2.14	3.26
Precision	November	25.86	25.11	29.06	3.41	1.85	2.37
Recall	January	99.69	99.45	99.69	0.31	0.99	0.27
Recall	May	99.33	99.46	99.27	1.15	0.38	0.49
Recall	August	99.85	99.41	99.50	0.24	0.79	0.36
Recall	November	99.78	99.54	99.71	0.25	0.31	0.18
F1 Score	January	40.58	38.64	44.09	3.88	2.06	3.18
F1 Score	May	40.12	40.06	45.25	4.28	2.53	3.34
F1 Score	August	39.69	39.53	45.12	3.68	2.61	3.95
F1 Score	November	40.96	40.07	44.95	4.24	2.32	2.90