A voxel-based fine-scale 3D landscape pattern analysis using laser scanner point clouds

The landscape pattern metrics can quantitatively describe the characteristics of landscape pattern and are widely used in various fields of landscape ecology.Due to the lack of vertical information,2D landscape metrics cannot delineate the vertical characteristics of landscape pattern.Based on the point clouds,a high-resolution voxel model and several voxel-based 3D landscape metrics were constructed in this study and 3D metrics calculation results were compared with that of 2D metrics.The results showed that certain quantifying difference exists between 2D and 3D landscape metrics.For landscapes with different components and spatial configurations,significant difference was disclosed between 2D and 3D landscape metrics.3D metrics can better reflect the real spatial structure characteristics of the landscape than 2D metrics.

Spatial pattern analysis of forest landscape in Changbai Mountain

Land use and land cover change is one of the important topics in the global change study with the development of satellite-based remote sensing technologies.This study employed 3D landscape pattern metrics to analyze the dynamics of land cover types around Heaven Lake in Changbai Mountain area from 2010 to 2015.The results indicated that forest land occupied the most proportion and increased from 61.9%in 2010 to 66%in 2015 due to government forest protection policy.The mean elevation of vegetation,including agriculture,fo-rest,grass and shrub was much lower compared with other land cover types(water,wetland,imperious land and bare land)in both 2010 and 2015.The elevation of agriculture land increased from 1700 m in 2010 to 1890 m in 2015 a decreased land proportion.Considering the adjacent relationship between the local agriculture land and forest land,the transformation from agriculture land to forest land was obvious in the lower elevation area.The study showed that the selected 3D landscape pattern metrics had the ability and efficiency to describe the spatiotemporal variations of mountainous landscape,and significant correlation existed between land cover and local terrain.

Vegetation ecological benefts index (VEBI): a 3D spatial model for evaluating the ecological benefits of vegetation

Urban population explosion may increase ecological environment discomfort,thereby affecting negatively humans’mental and physical performance.Therefore,it is important to detect and monitor vegetation and predict its ecological benefits.The complex composition of urban environment ground objects,such as steel roofs,plastic courts,and building shadows,significantly interferes with vegetation detection and monitoring.The optimized hyperspectral image-based vegetation index(OHSVI)constructed in this study effectively solves this problem.However,it is difficult to accurately predict the ecological benefits of vegetation based on the two-dimensional vegetation information extracted based on remote sensing images;this is related to the three-dimensional(3D)structure of vegetation and the 3D pattern of buildings.Therefore,wefirst proposed the vegetation ecological benefits index(VEBI)based on the 3D structure of vegetation to reveal how vegetation acts on its 3D surroundings.The method was tested in a playground,an academic building,and a parking space.The results showed that the vegetation extraction accuracy of the OHSVI exceeded 93%,which is better than that of the existing indices.Ourfindings suggest that VEBI may be efficient in predicting 3D vegetation ecological benefits combined with remote sensing and lidar datasets.