Monitoring the Invasion of Spartina alterniflora Using Very High Resolution Unmanned Aerial Vehicle Imagery in Beihai, Guangxi (China)

Figure 3

Three typical regions from north of Dandou Sea ((a1) to (a3)), south of Dandou Sea ((b1) to (b3)), and Shatian port ((c1) to (c3)) were selected. (a1)–(c1) shows the original VHR image; the segmentation parameters of the three parts are scale 40, shape 0.1, and compactness 0.5 and the results are (a2)–(c2); the features for extracting S. alterniflora from (a3) and (c3) are “Mix diff ≤ 0.09, brightness: 105–136” and the features for extracting S. alterniflora from (b3) are “Mix diff ≤ 0.08, brightness ≤ 136.”