Evaluation of the Threshold for an Improved Surface Water Extraction Index Using Optical Remote Sensing Data

Table 4

Summary of the classification accuracy of the AWEI threshold improvement based on the results of the natural break threshold to detect lake surface water, tested at several locations that could represent other lake characteristics in Indonesia.

Test site	Threshold	Land cover class	User Accu. (%)	Product Accu. (%)	Kappa	Overall Accu. (%)
Maninjau	≥−0.232	Water	97.24	99.41	0.98	99.55
		Nonwater	99.91	99.57
Singkarak	≥−0.232	Water	97.18	99.74	0.98	99.55
		Nonwater	99.96	99.51
Kerinci	≥−0.232	Water	95.99	99.72	0.97	99.43
		Nonwater	99.96	99.38
Rawa Pening	≥−0.232	Water	82.71	87.79	0.73	93.58
		Nonwater	98.40	98.01
Batur	≥−0.232	Water	96.46	97.75	0.97	99.34
		Nonwater	99.71	99.54
Sentarum	≥−0.232	Water	87.99	91.92	0.79	94.33
		Nonwater	99.61	99.39
Jempang	≥−0.232	Water	83.85	76.66	0.76	93.83
		Nonwater	95.56	97.15
Tempe	≥−0.232	Water	77.98	99.37	0.85	95.77
		Nonwater	99.88	95.14
Matano	≥−0.232	Water	97.68	99.18	0.98	99.44
		Nonwater	99.82	99.49
Poso	≥−0.232	Water	98.77	99.56	0.98	99.59
		Nonwater	99.86	99.59
Limboto	≥−0.232	Water	91.16	93.26	0.91	98.23
		Nonwater	99.13	98.84
Tondano	≥−0.232	Water	94.97	98.51	0.96	98.86
		Nonwater	99.69	98.93
Sentani	≥−0.232	Water	97.19	92.39	0.94	98.20
		Nonwater	98.41	99.43
Rawa Danau	≥−0.232	Water	-	-	-	-
		Nonwater	-	-	-	-