Quantification of Loess Landforms from Three-Dimensional Landscape Pattern Perspective by Using DEMs

Abstract

Quantitative analysis of the differences and the exploration of the evolution models of different loess landform types are greatly important to the in-depth understanding of the evolution process and mechanism of the loess landforms. In this research, several typical loess landform areas in the Chinese Loess Plateau were selected, and the object-oriented image analysis (OBIA) method was employed to identify the basic loess landform types. Three-dimensional (3D) landscape pattern indices were introduced on this foundation to measure the morphological and structural features of individual loess landform objects in more detail. Compared with the traditional two-dimensional (2D) landscape pattern indices, the indices consider the topographic features, thereby providing more vertical topographic information. Furthermore, the evolution modes between different loess landform types were discussed. Results show that the OBIA method achieved satisfying classification results with an overall accuracy of 88.12%. There are evident differences in quantitative morphological indicators among loess landform types, especially in indicators such as total length of edge, mean patch size, landscape shape index, and edge dimension index. Meanwhile, significant differences are also found in the combination of loess landform types corresponding to different landform development stages. The degree of surface erosion became increasingly significant as loess landforms developed, loess tableland area rapidly reduced or even vanished, and the dominant loess landform types changed to loess ridge and loess hill. Hence, in the reconstruction and management of the Loess Plateau, the loess tableland should be the key protected loess landform type. These preliminary results are helpful to further understand the development process of loess landforms and provide a certain reference for regional soil and water conservation.

Three-Dimensional Spatial Distribution and Influential Factors of Soil Total Nitrogen in a Coal Mining Subsidence Area

“…Soil is a continuous three-dimensional entity with spatial variation in both horizontal and vertical directions. By studying soil characteristics through three-dimensional spatial distribution, a more comprehensive understanding of soil quality can be obtained [30,31]. At present, research on the spatial variation in soil properties mainly focuses on the two-dimensional horizontal direction, and the properties of different soil layers are discontinuous in the vertical direction.…”

Groundwater recharge in typical geomorphic landscapes and different land use types on the loess plateau, China

“…The Loess Plateau landform types can be approximately categorized as loess hilly‐gully, loess plateau landforms, and loess ridges (i.e., mountains) (Wei et al, 2021; Wu et al, 2020). Therefore, we chose the Longdong Loess Plateau, which contains typical loess hilly–gully and ridge landforms near Pingliang and Loess Plateau landforms near Qingyang, to analyse and compare groundwater conditions for different land use types.…”

Evaluation of DEM Accuracy Improvement Methods Based on Multi-Source Data Fusion in Typical Gully Areas of Loess Plateau

“…This unique landform developed 2 of 19 under the action of internal and external forces such as water and heat, making it one of the most valuable regions for geosensitive research in the world. With the continuous improvement in the methods of digital terrain technology, the complex and unique terrain of the Loess Plateau also provides a unique sample for the in-depth study of digital terrain analysis [1]. The publicly available digital elevation model (DEM) provides the necessary data basis for digital topography research of the Loess Plateau.…”