Digital Soil Mapping in the Absence of Field Training Data: A Case Study Using Terrain Attributes and Semiautomated Soil Signature Derivation to Distinguish Ecological Potential

Table 1

Correlation matrix for six spectral bands and four normalized indices calculated from a 24 Feb 2002 Landsat ETM+ image. Normalized indices were calculated using ETM+ spectral bands: gypsic index [(B5−B7)/(B5+B7)] from [16] and iron oxide index [(B3−B1)/(B3+B1)] from ERDAS Imagine (v.9.3, ERDAS, Inc., Norcross, Ga, USA) software.

	B1 Blue	B2 Green	B3 Red	B4 NIR	B5 SWIR	B7 SWIR	B5-B7/ B5+B7	B3-B7/ B3+B7	B3-B2/ B3+B2	B3-B1/ B3+B1
Band 1	1.000	0.838	0.667	0.610	0.440	0.438	−0.128	0.555	−0.052	−0.021
Band 2		1.000	0.908	0.868	0.739	0.742	−0.232	0.450	0.205	0.449
Band 3			1.000	0.964	0.893	0.895	−0.269	0.334	0.596	0.729
Band 4				1.000	0.929	0.904	−0.177	0.237	0.586	0.731
Band 5					1.000	0.959	−0.144	−0.042	0.669	0.791
Band 7						1.000	−0.416	−0.121	0.672	0.802
B5-B7/ B5+B7							1.000	0.272	−0.203	−0.267
B3−B7/ B3+B7								1.000	−0.091	−0.066
B3−B2/ B3+B2									1.000	0.849
B3−B1/ B3+B1										1.000