2023 Volume 28 Issue 1-2 Pages 83-95
Assuming the Japanese National Forest Inventory data (NFI data) as true values, the accuracy of the Ministry of the Environment vegetation map for the whole of Japan was assessed (The 2,112 vegetation maps that had been completed as of November 2019). The NFI data were overlaid on the vegetation map to determine whether there was a match between the two. Comparisons were carried out between forest and non-forest, followed by conifer plantations and other forests. Data from the third period (2009-2013) of the NFI were used. The legend of the vegetation map was used to categorize forest and non-forest, as well as conifer plantation and other forest. Error matrix and Kappa coefficient were employed to quantify the degree of agreement between vegetation maps and NFI data. The results of this study indicated that the Kappa coefficients of the vegetation map for the NFI data as true values was 0.86 for forest and non-forest, and 0.59 for conifer plantations and other forests, respectively. The calculation of the Kappa coefficients for each area of the plane rectangular coordinate system showed areas of relatively high and low accuracy. This paper has successfully enabled the accuracy assessment of vegetation maps to be carried out at a national scale.
