PE&RS March 2016 full version - page 208

Wilcoxon signed rank tests found three comparisons that
were significant (Table 7). For zone 23, the OOB predictions
for the model II regression mosaic were significantly differ-
ent than the OOB predictions derived for both the median and
maximum NDVI composites. The OOB predictions derived us-
ing the model II regression mosaic were 2 percent lower than
the PTCC predictions derived using the median and maximum
NDVI composites. For zone 54, the OOB predictions derived us-
ing the maximum NDVI composite were significantly different
than the OOB predictions derived using the median compos-
ite. The OOB predictions derived using the median composite
were 5 percent higher than the OOB predictions derived using
the maximum NDVI composite. There were no other significant
differences between the OOB predictions derived using the
different composite types.
To further examine differences in PTCC predictions derived
using the different composite types, PTCC estimates and 95
percent confidence limits were derived for the median com-
posite, maximum NDVI composite, and the model II regression
mosaic. Table 8 presents the percentage of all PTCC values in a
reference image (left column) that fell outside the 95 percent
confidence limits as predicted by the comparative image (top
T able 6. Percent Tree-Canopy Cover Random Forest Models were Created
for the Multi -Resolution L and C haracteristic Mapping Zones 16, 23, 48,
54, and 59. The Random Forest Models Out- of-Bag Percent Variance
Explained and the Mean of Squared Residuals are Shown Here
Percent Variance
Explained
Mean of Squared
Residuals
Zone 16
Max NDVI Composite 62.5 233.7
Median Composite 63.9 225.0
Model II Regression Mosaic 64.0 224.1
Zone 23
Max NDVI Composite 50.6 163.4
Median Composite 50.3 164.5
Model II Regression Mosaic 51.8 159.7
Zone 48
Max NDVI Composite 80.6 321.9
Median Composite 85.9 234.3
Model II Regression Mosaic 84.1 264.4
Zone 54
Max NDVI Composite 81.5 232.7
Median Composite 85.2 186.2
Model II Regression Mosaic 81.0 239.4
Zone 59
Max NDVI Composite 76.6 338.0
Median Composite 80.9 275.4
Model II Regression Mosaic 79.0 302.7
T able 7. Results of the Wilcoxon Signed Rank Paired T ests Conducted on the
Random Forest Out-of-Bag Percent Tree-Canopy C over Predictions that were
Derived Using the Different Image Types. The Analysis was Done on the M ulti-
Resolution L and Characteristic M apping Zones 16, 23, 48, 54, and 59
Image Type 1 Image Type 2 p-value
Zone 16
Max NDVI Composite Median Composite 0.90
Max NDVI Composite Model II Regression Mosaic 0.93
Median Composite Model II Regression Mosaic 0.96
Zone 23
Max NDVI Composite Median Composite 0.14
Max NDVI Composite Model II Regression Mosaic 0.04
Median Composite Model II Regression Mosaic 0.02
Zone 48
Max NDVI Composite Median Composite 0.73
Max NDVI Composite Model II Regression Mosaic 0.11
Median Composite Model II Regression Mosaic 0.10
Zone 54
Max NDVI Composite Median Composite 3.E-03
Max NDVI Composite Model II Regression Mosaic 0.54
Median Composite Model II Regression Mosaic 0.24
Zone 59
Max NDVI Composite Median Composite 0.11
Max NDVI Composite Model II Regression Mosaic 0.06
Median Composite Model II Regression Mosaic 0.46
Table 8. Percentage of All Percent Canopy-Cover Values in a Reference Image (Left Column) that Fall Outside the 95 Percent Confidence Limits as Predicted
by the Comparative I mage (Top Row.) The Smaller the Number, the Fewer Significant Differences between the I mage Types. This Analysis was Done on the
Multi-Resolution Land Characteristic Mapping Zones 16, 23, 48, 54, and 59
Zone 16 Zone 23
Comparative Images Comparative Images
Reference Images Max NDVI Median Model II Reference Images Max NDVI Median Model II
Max NDVI 0.04% 0.20% Max NDVI 0.04% 1.80%
Median 0.02% 0.08% Median 0.00% 1.39%
Model II 0.15% 0.04% Model II 0.03% 0.03%
Zone 48 Zone 54
Comparative Images Comparative Images
Reference Images Max NDVI Median Model II Reference Images Max NDVI Median Model II
Max NDVI 10.80% 9.24% Max NDVI 3.64% 3.19%
Median 1.09% 2.95% Median 0.01% 1.66%
Model II 2.44% 5.89% Model II 2.72% 3.85%
Zone 59
Comparative Images
Reference Images Max NDVI Median Model II
Max NDVI 7.28% 5.22%
Median 0.76% 2.76%
Model II 1.80% 5.73%
208 March 2016 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING