Luo Y.,Chengdu University of Technology |
Yu H.,CAS Chengdu Institute of Mountain Hazards and Environment |
Wang Y.,Sichuan Institute of Land Planning and Survey |
Zheng Z.-J.,The Geological Environment Monitoring Station |
Wang X.,China Southwest Geotechnical Investigation & Design Institute Co.
Journal of Donghua University (English Edition) | Year: 2015
Compared with previous studies, the research attempted to establish the appropriate quantitative models to explain the relations between settlement density Di and geographic factors, which could make a scientific guidance to the mountain settlements planning. Five factors, including slope, relief amplitude, distance to river, distance to cultivated land, and distance to road, were identified through principal component analysis (PCA). The inherent relations between five factors and Di (settlement density) were modeled by regression analysis. The results are as follows. (1) The associations among Di and slope, relief amplitude, river, road are better modeled by the exponential decay line; with the buffer distance of slope, relief amplitude, distance to river and distance to road increasing, Di decreases. (2) The associations between Di and cultivated land are better modeled by the quadratic polynomial line; with the buffer distance of cultivated land increasing, Di increases first, and then dramatically decreases. (3) The area within 500 m from the road, within 500 m from the cultivated land, within 1600 m from the river, within the relief amplitude of 30-200 m, and the area within the slope of 0°-10° are the fitting land for settlements, and it is very important to lay the mountain settlements on those optimized regions. Copyright © 2015 Editorial Department of Journal of Donghua University, Shanghai, China. All rights reserved.
Hui Y.,CAS Chengdu Institute of Mountain Hazards and Environment |
Yong L.,Chengdu University of Technology |
Shaoquan L.,CAS Chengdu Institute of Mountain Hazards and Environment |
Yong W.,Sichuan Institute of Land Planning and Survey |
And 2 more authors.
Environmental Earth Sciences | Year: 2015
Topographic analysis is an important component of research on geomorphologic and surface process. The threshold value method was used to obtain the topographic relief of the study area based on 1:100,000 digital elevation model (DEM). Through mean change-point analysis method, the optimal statistical unit of topographic relief was determined as 0.15 km2. The swath profile method was used to analyze topographic and geomorphological characteristics of the Three Gorges Area. Combined with geosciences research method, the spatial analysis technique was applied to quantitatively analyze the relationship between topographic relief and settlements as well as settlement density (SD) in the Three Gorges Area. The results show that: (1) The Three Gorges Area is mainly covered by hilly regions, accounting for 58.93 % of the study area. The cascade structure of planation surface is very significant. Northeast undulating mountains have greater topographic relief. The peaks are generally located at the elevation from 1500 to 2000 m, i.e., high planation surface; southwest low mountain valley regions have greater topographic relief. The summit level is generally located at the elevation from 500 to 1500 m, i.e., low planation surface with an elevation from 1200 to 1500 m, pediment with an elevation from 500 to 1200 m; the general elevation gradually decreases from east to west, showing a geomorphological shape as narrow ridge and wide valley. (2) Topographic relief is a key factor influencing the spatial distribution of mountain settlements. In the vertical direction, the mountain settlements have significant change characteristics. In the horizontal direction, the mountain settlements have significant spatial aggregation characteristics. © 2015, Springer-Verlag Berlin Heidelberg.
Liu Z.-C.,Sichuan Institute of Land Planning and Survey |
Liu Z.-C.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Engineering |
Yang W.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Engineering |
Wang W.,Sichuan Institute of Land Planning and Survey |
Zhang P.,Sichuan Institute of Land Planning and Survey
Geology in China | Year: 2015
A microbial mud mound was found for the first time in the Middle Permian Qixia Formation of Huayin Xikou area. This mud mound is supported by mud, the primary builder is fungi, followed by invertebrates. The species diversity is low, with high species richness. The main lithology includes bioclastic micritic limestone and thrombolite. The mud mound can be divided into mound-core, mound-flank, and mound-base. According to the results of sample analysis of the Qixia Formation, all of the paleosalinity Z values >122, δ13C > 0; δ18O values are between-6.33‰ and -4.42‰, the ancient water temperature values are between 33.60°C and 24.26°C, V/(V+Ni) ratio is 0.51228, and U/Th ratio is 8.28205, suggesting that the environment of Qixia period was characterized by relatively deep water, relatively weak hydrodynamics, higher temperature, high salinity and anoxic nature. Such an environment was conducive to the development of microbial mud mound, and affected the development and growth of reef-building organisms. This was one of the reasons leading to the lack of skeleton of the reef in Qixia Formation.
Liao S.,Henan University |
Liao S.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research |
Cao J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research |
Cao J.,Sichuan Institute of Land Planning and Survey |
And 2 more authors.
Applied Mechanics and Materials | Year: 2013
With remote sensing mapping for land cover of China at scale of 1 to 250,000 as an example, we analyzed main quality problems related to cartographic specifications. In order to improve efficiency of checking the problems and to make checking and evaluating results more objective, we designed and developed a set of quality check and evaluation system based on cartographic specification in loose coupling mode with open source software tools. The actual evaluation results from the system demonstrated that the land cover data generally met requirements of cartographic specifications. © (2013) Trans Tech Publications, Switzerland.
Deng B.,Chengdu University of Technology |
Yang W.-N.,Chengdu University of Technology |
Mu N.,Sichuan Institute of Land Planning and Survey |
Zhang C.,Chengdu University of Technology
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2016
Vegetation water content is an important indicator of vegetal state, and a vital parameter of studying agriculture, ecological and hydrological. The diagnosis of vegetation water content has great significance for forest fire forecast and natural vegetation drought condition monitoring. The correlation analysis of the vegetation spectral reflectance and vegetation water content shows that the relativity between the spectral reflectance of different wavelengths and the vegetation water content varies considerably. The spectral reflectance of red band of visible light (620~700 nm) and the near-infrared band(800~1 350, 1 600~1 950, 2 200~2 400 nm) had a higher correlation with the vegetation water content. The slope angle indexes were used as parameters for estimating the vegetation water content based on analyzing the relation between the slope angle indexes and vegetation water content. An evaluation model of vegetation water content was set up by utilizing statistical linear regression model method. The band of 660, 850, 1 630, 2 200 nm were selected as RED, NIR, SWIR1 and SWIR2 band value of the slope angle index based on the analysis of the correlation between spectral reflectance and vegetation water content. A large amount of vegetation spectral information and vegetation water content were collected in the study area(the upstream of Minjiang River), and the linear regression model of the slope angle index (SANI, SASI, ANIR) and vegetation water content (FMC) was build. The linear regression model of ANIR and FMC has the highest of linear fitting and the linearity is up to 0.791. The near infrared angle index(ANIR)was improved on the basis of the analysis the linear regression results of angle slope vegetation index and water content. Near infrared angle normalized index (NANI) and near infrared angle slope index (NASI) were defined, and the linear regression model was established. Compared with the slope angle index (SANI, SASI, ANIR) which were proposed by Palacios-Orueta, NANI had more advantages in the vegetation water content inversion in the study area. The determination coefficient (R2) of the inversion model increased from 0.791 to 0.853, and root-mean-square error (RMSE) reduced from 0.047 to 0.039. Angle slope index had higher linear fitting and estimation accuracy by improving the angle of slope index. NANI and FMC linear regression model was established to estimate the vegetation water content in the study area. In this paper, the main innovation point is that the slope angle index NANI and NASI has been proposed on the basis of predecessors' research results, and the improved angle slope index has higher linear fitting and estimation accuracy compared with SANI, SASI, ANIR. © 2016, Peking University Press. All right reserved.