# Application of Compound Terrain Factor LSW in Vegetation Cover Evaluation
###### Abstract
Some scholars used multi-temporal remote sensing images and digital elevation model (DEM) as data sources, along with trend analysis, factor detection, and interaction detection methods to try to decipher the extent to which human activities have driven vegetation changes, taking river valleys and river headwater regions as objects [12; 13]. Through geographically weighted regression, multiple regression, and threshold regression, some researchers have revealed the multi-scale spatial relationships between topographic attributes and vegetation cover [14; 15]. These findings provide a scientific basis for ecological environmental protection and assessment. Furthermore, some scholars have considered vegetation and topography as key elements in evaluating ecosystem services, and have also conducted topographic correlations for ecosystems with different vegetation types to offer theoretical guidance and decisions for sustainable development in high plateaus and mountainous areas [16; 17]. However, the studies of the relevance between vegetation cover and topography are confined to the traditional simple topographic factors such as slope and elevation, which cannot reveal the hidden laws in depth due to the limitations of these factors. Besides, some scholars have taken erosion control as an entry point to differentiate how various environmental factors, such as climate, topography, vegetation, and human activities, contribute to erosion changes [18; 19], while seasonal variations are taken into account. Additionally, some scholars developed the SLTNI (local window terrain niche index based on similar habitat) and compared it to the traditional TNI (terrain niche index) and LTNI (local window terrain niche index) to demonstrate its superiority in assessing vegetation cover [20]. Nevertheless, the slope body exists as an independent natural topographic entity, but few scholars have explored the linkages between slope development, soil erosion and vegetation growth from an integrated perspective [21; 22]. Taking the morphological characteristics of the slope surface as the basis, scholars have respectively explored the influence of slope length (L) and slope width factor (W) on soil erosion [23; 24], as well as investigated the influence of the slope factor (S) on the sediment-discharge relationship [25; 26]. These studies present valuable decision-making knowledge to serve for gully erosion control, and they also provide ideas for finding novel methods of assessing vegetation growth potential. Synthesizing existing studies related to topography and vegetation growth, we infer that there is an important association between slope conditions and vegetation development. As a comprehensive slope indicator that balances the contribution of each factor, LSW (Length, Slope and Width Factor) is the potential factor to fill this gap, so exploring the relationship between LSW and vegetation growth potential becomes the key point of this paper. The above analysis suggests that topographic factors and vegetation indices complement each other and provide a key basis for land cover classification [27]. This study intends to elucidate the vegetation cover mechanism from the perspective of digital terrain analysis (DTA) with the following objectives: (1) to take vegetation cover evaluation as a starting point and fill in the local one-sidedness of image spectral information from the perspective of data sources; (2) to explain the association between the novel factor LSW and soil erosion in qualitative and quantitative terms; (3) to investigate the suitability of the bivariate model (certainty factor, CF) applied to the assessment of vegetation growth and development, and to make directional attempts for the application of the LSW.