Comparative study on crown closure estimations using two different remote sensing data: Landsat ETM+ and IKONOS

Figures & data

Figure 1. Map of the study area.

Figure 2. Scatter plots of crown closure (%) against DN of each ETM image band.

Table 1. Statistical analysis between single bands with crown closure in Landsat ETM image.

Crown closure	ETM 1	ETM 2	ETM 3	ETM 4	ETM 5	ETM 7
Correlation coefficient (r)	0.373	0.411	0.381	0.715	0.569	0.519
R-squared (R^2)	0.139	0.169	0.145	0.511	0.323	0.269
Residual standard error (rse)	0.129	0.127	0.129	0.097	0.114	0.119
Note: Bold number shows the highest correlation.

Table 2. Statistical analysis between single bands with crown closure in IKONOS image.

Crown closure	IKONOS Band 1	IKONOS Band 2	IKONOS Band 3	IKONOS Band 4
Correlation coefficient (r)	–	0.359	0.385	0.829
R-squared (R^2)	–	0.129	0.148	0.687
Residual standard error (rse)	–	0.131	0.129	0.089
Note: Bold number shows the highest correlation.

Figure 3. Scatter plots of crown closure (%) against DN of each IKONOS image band.

Figure 4. Scatter plots of NDVI against DN of each ETM image band.

Figure 5. Scatter plots of NDVI against DN of each IKONOS image band.

Table 3. Correlation analysis between NDVI and digital number values in ETM image.

NDVI	ETM 1	ETM 2	ETM 3	ETM 4	ETM 5	ETM 7
Correlation coefficient (r)	0.460	0.511	0.419	0.886	0.734	0.631
R-squared (R^2)	0.211	0.261	0.176	0.785	0.539	0.398
Residual standard error (rse)	0.065	0.063	0.067	0.034	0.050	0.057
Note: Bold number shows the highest correlation.

Figure 6. Scatter plots of crown closure against NDVI obtained from Landsat and IKONOS images.

Table 4. Correlation analysis between NDVI and digital number values in IKONOS image.

NDVI	IKONOS Band 1	IKONOS Band 2	IKONOS Band 3	IKONOS Band 4
Correlation coefficient (r)	–	0.380	0.367	0.781
R-squared (R^2)	–	0.144	0.135	0.610
Residual standard error (rse)	–	0.089	0.091	0.066
Note: Bold number shows the highest correlation.

Table 5. Correlation analysis between NDVI (Landsat)-NDVI (IKONOS) and crown closure.

Crown closure	NDVI (Landsat)	NDVI (IKONOS)
Correlation coefficient (r)	0.794	0.871
R-squared (R^2)	0.630	0.759
Residual standard error (rse)	0.084	0.068
Note: Bold number shows the highest correlation; italicized number shows the lowest correlation.