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1.
DEM栅格分辨率对丘陵山地区定量土壤-景观模型的影响 总被引：2，自引：2，他引：0
基于数字高程模型（Digital Elevation Model,DEM）的定量土壤-景观模型的精度依赖于DEM栅格分辨率,而DEM栅格分辨率如何影响土壤-景观模型及其预测精度目前研究较少。以西南丘陵山地区一典型汇水盆地为研究对象,以该区2.5、5、10、20和30 m DEM为基础,利用逐步线性回归方法建立起研究区不同分辨率下的定量土壤-景观模型,并应用这些模型预测研究区内土壤表层碱解氮含量的空间分布,进而比较DEM不同分辨率下土壤-景观模型及其预测精度。结果表明,随着DEM栅格分辨率的降低,比汇水面积、地形湿度指数的均值逐渐增加;平均坡度逐渐降低;曲率变化的范围逐渐减小。地形指数的这一变化规律对土壤-景观模型及其预测结果产生显著影响,模型的校正决定系数、平均绝对误差和均方根误差都以5 m栅格分辨率为转折点,分辨率低于5 m,模型的校正决定系数显著减小,平均绝对误差和均方根误差显著增加。 相似文献
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突变地形特征在DEM上的表达 总被引：1，自引：1，他引：0
黄土高原南部高塬沟壑区的地形,存在比较明显的塬边线和沟缘线等突变地形特征线,而这种地形特征在DEM表面的表达却缺乏必要研究。选长武县为研究区,将1:50 000地形图（等高线、高程点和河流等专题层）及其手工提取的地形特征线（塬边线、沟缘线和坡脚线）数字化;利用多要素构TIN方法和Hutchinson插值方法,分别在有无地形特征线参与的情况下建立10 m分辨率规则格网的DEM;利用地图代数运算和频率统计等方法,比较分析所建DEM表面的高程、坡度和剖面曲率等地形属性特征。结果表明:在ANUDEM插值（Hutchinson算法）情况下,地形特征线的参与,可显著改善DEM对地形特征的表达,既避免了平三角,又兼顾了地形的光滑和连续性特征;而在构TIN建立DEM的情况下则无明显影响。 相似文献
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基于地形因子和随机森林的丘陵区农田土壤有效铁空间分布预测 总被引：5，自引：1，他引：4
为了掌握丘陵地区农田土壤有效铁含量及其空间分布,本文以重庆市江津区永兴镇内同源成土母质的典型丘陵(2 km2)为研究区,采集309个土壤样点,利用普通克里格(Ordinary Kriging,OK)、多元线性回归(Multiple Linear Regression,MLR)、随机森林(Random Forest,RF)模型,结合高程、坡度、坡向、谷深、平面曲率、剖面曲率、汇聚指数、相对坡位指数、地形湿度指数等地形因子对土壤有效铁进行空间分布预测,并通过85个验证点评价、筛选预测模型。结果表明:1)土壤有效铁与谷深、地形湿度指数存在极显著水平正相关关系,与坡度、平面曲率、剖面曲率、汇聚指数、相对坡位指数存在极显著水平负相关关系。2)随机森林模型的预测精度明显高于多元线性回归和普通克里格插值,其平均绝对误差为22.33 mg·kg-1、均方根误差为27.98 mg·kg-1、决定系数为0.76,是研究区土壤有效铁含量空间分布的最适预测模型。3)地形湿度指数和坡度是影响该区域土壤有效铁含量空间分布的主要地形因子。土壤有效铁与坡度、谷深、平面曲率、剖面曲率、汇聚指数、相对坡位指数、地形湿度指数均达到极显著水平相关关系。4)研究区土壤有效铁含量范围为3.00~276.97 mg?kg-1,水田有效铁含量大于旱地;土壤有效铁具有较强的空间相关性,土壤有效铁含量空间变异主要受到结构性因素的影响。可见,基于地形因子的随机森林预测模型可以较好地解释丘陵区农田土壤有效铁含量的空间变异,研究结果为丘陵区土壤中、微量元素含量及空间分布预测提供方法借鉴和理论依据。 相似文献
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The main objectives of this study were to model the relationship between WRB-1998 soil groups and terrain attributes and predict the spatial distribution of the soil groups using digital terrain analysis and multinomial logistic regression integrated in GIS in the Vestfold County of south-eastern Norway. A digital elevation model of 25 meter grid resolution was used to derive fifteen terrain attributes. A digitized soil map of thirteen WRB soil groups at the scale of 1:25,000 was used to obtain the reference soil data for model building and validation. First, the relationships between the soil groups and the terrain attributes were modeled using multinomial logistic regression. Then, the probability that a given soil type is present at a given pixel was determined from the logit models in ARCGIS to continuously map each soil group's spatial distribution. Elevation, flow length, duration of daily direct solar radiation, slope, aspect and topographic wetness index were found to be the most significant terrain attributes correlating with the spatial distribution of the soil groups. The prediction showed higher mean probability values for each soil group in the areas actually covered by that soil group compared to other areas, indicating the reliability of the prediction. However, the prediction performed poorly for soil groups that are not greatly influenced by topography but by other factors such as human activities. 相似文献
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Topographic controls on the spatial distribution of ground cover in the Tabernas badlands of SE Spain 总被引：1，自引：0，他引：1
The relationships between the spatial distribution of ground-cover and terrain attributes were examined in the Tabernas badlands (SE Spain) in order to understand the terrain-dependent driving forces of the spatially heterogeneous ground cover. Ground cover was mapped in the field and terrain attributes were derived from a 1-m resolution Digital Elevation Model (DEM). The association of spatial distribution of the landforms resulting from a regionalisation (using a nonhierarchical classification of the topographic overlays) and the ground-cover pattern was proved. From the analysis of relationships between terrain attributes and proportional abundance of ground-cover types, it was found that ground cover is arranged along topographic gradients: plant-covered surfaces are more abundant on low slope angles, concave slopes, relatively large contributing areas and with low length slope factor values. Unvegetated surfaces show contrary trends and lichens are associated with intermediate conditions. Relationships with local terrain attributes, such as slope angle or elevation, are more pronounced than those with terrain attributes related to sediment and water transfer, such as contributing area, wetness index or length slope factor which could be explained by the heterogeneity of runoff that is usually shorter than the hillslope length. The relationships established between the spatial distribution of ground-cover types and terrain attributes provide the basis for future development of a tool for mapping spatial distribution of ground cover in similar areas from only topographic information. 相似文献
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ANN‐based pedotransfer and soil spatial prediction functions for predicting Atterberg consistency limits and indices from easily available properties at the watershed scale in western Iran 
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下载免费PDF全文 Atterberg consistency limits (liquid limit, LL; plastic limit, PL; shrinkage limit, SL) and indices (plasticity index, PI; friability index, FI) are useful indicators of soil mechanical behaviour. This study was conducted to evaluate the use of soil and environmental data for predicting Atterberg limits or indices using artificial neural network (ANN) models at the watershed scale in western Iran. The LL, PL, SL, PI, FI, particle size distribution, organic matter (OM) and calcium carbonate equivalent (CCE) were measured in soil samples collected from 113 locations. Three sets of readily available properties were employed as inputs. The first of these data sets or models consisted of soil properties. The second included topographic attributes and normalized difference vegetation index (NDVI), and the third was a combination of soil, topographic attributes and NDVI. Developed ANN models could explain a majority of the variability (62–94%) in Atterberg limits and indices. Greatest and poorest performances were attributed to the third and first models, respectively. No significant efficacy difference was observed between the second and third models. Therefore, the second data set with its readily available environmental variables is suggested for use in predicting Atterberg limits and indices at the regional scale. Sensitivity analysis showed that NDVI, OM, clay content, CCE and topographic attributes (wetness index, elevation, plan curvature and slope) could explain much of the variance associated with Atterberg limits and indices at the watershed scale in western Iran. 相似文献
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Qiyong Yang Fawang Zhang Zhongcheng Jiang Wenjun Li Jianbing Zhang Faming Zeng Hui Li 《Journal of Soils and Sediments》2014,14(9):1568-1576
Purpose
Soil depth generally varies in peak-cluster depression regions in rather complex ways. Because conventional soil survey methods in these regions require a considerable amount of time, effort, and consequently relatively large budget, new methods are required in karst regions.Materials and methods
This study explored the relationship between soil depth and terrain attributes abstracted from digital elevation models (DEMs) at different spatial resolutions in the Guohua Karst Ecological Experimental Area, a representative region of peak-cluster depression in Southwest China. A uniform 140 m?×?140 m grid combined with representative hillslope methodology was used to select 171 sampling points where soil depth was measured. Nine primary and secondary terrain attributes, such as elevation, slope, aspect, especial catchment area, wetness index, length-slope factor, stream power index, relief degree of land surface, and distance from ridge of mountains, were computed from DEMs at different spatial resolutions. The optimal DEM spatial resolution was determined by Grey relational analysis (GRA) to reflect the correlations between soil depth and terrain attributes.Results and discussion
GRA revealed that the 10-m spatial resolution DEM can best reflect the relationship between soil depth and terrain attributes; therefore, the terrain attributes at this resolution were used for multiple linear stepwise regression (MLSR) analysis. The result of MLSR indicated that slope, TWI, and elevation could explain about 61.4 % of the total variability in soil depth in the study area.Conclusions
The terrain attributes of slope, WTI and elevation can be used to evaluate soil depth in this region very well. This proposed approach may be applicable to other peak-cluster depression regions in the karst areas at a larger scale. 相似文献9.
结合统计和数字地形数据的可视化方法预测土壤深度 总被引：2，自引：0，他引：2
F. M. ZIADAT 《土壤圈》2010,20(3):361-367
Information about the spatial distribution of soil attributes is indispensable for many land resource management applications; however, the ability of soil maps to supply such information for modern modeling tools is questionable. The objectives of this study were to investigate the possibility of predicting soil depth using some terrain attributes derived from digital elevation models (DEMs) with geographic information systems (GIS) and to suggest an approach to predict other soil attributes. Soil depth was determined at 652 field observations over the Al-Muwaqqar Watershed (70 km2) in Jordan. Terrain attributes derived from 30-m resolution DEMs were utilized to predict soil depth. The results indicated that the use of multiple linear regression models within small watershed subdivisions enabled the prediction of soil depth with a difference of 50 cm for 77% of the field observations. The spatial distribution of the predicted soil depth was visually coincided and had good correlations with the spatial distribution of the classes amalgamating three terrain attributes, slope steepness, slope shape, and compound topographic index. These suggested that the modeling of soil-landscape relationships within small watershed subdivisions using the three terrain attributes was a promising approach to predict other soil attributes. 相似文献
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Yazhou SUN Wenxuan GUO David C. WEINDORF Fujun SUN Sanjit DEB Guofeng CAO Jasmine NEUPANE Zhe LIN Abir RAIHAN 《土壤圈》2021,31(5):705-714
Excess calcium(Ca) in soils of semi-arid and arid regions has negative effects on soil structure and chemical properties, which limits the crop root growth as well as the availability of soil water and nutrients. Quantifying the spatial variability of soil Ca contents may reveal factors influencing soil erosion and provide a basis for site-specific soil and crop management in semi-arid regions. This study sought to assess the spatial variability of soil Ca in relation to topography, hydraulic attributes, and soil types for precision soil and crop management in a 194-ha production field in the Southern High Plains of Texas,USA. Soils at four depth increments(0–2, 0–15, 15–30, and 30–60 cm) were sampled at 232 points in the spring of 2017. The Ca content of each sample was determined with a DP-6000 Delta Premium portable X-ray fluorescence(PXRF) spectrometer. Elevation data was obtained using a real-time kinematic GPS receiver with centimeter-level accuracy. A digital elevation model(DEM) was derived from the elevation data, and topographic and hydraulic attributes were generated from this DEM. A generalized least-squares model was then developed to assess the relationship between soil Ca contents of the four layers and the topographic and hydraulic attributes. Results showed that topographic attributes, especially slope and elevation, had a significant effect on soil Ca content at different depths(P 0.01). In addition, hydraulic attributes, especially flow length and sediment transport index(STI), had a significant effect on the spatial distribution of soil Ca. Spatial variability of soil Ca and its relationships with topographic and hydraulic attributes and soil types indicated that surface soil loss may occur due to water or wind erosion, especially on susceptible soils with high slopes. Therefore, this study suggests that the application of PXRF in assessing soil Ca content can potentially facilitate a new method for soil erosion evaluation in semi-arid lands. The results of this study provide valuable information for site-specific soil conservation and crop management. 相似文献
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黄土丘陵沟壑区1∶1万及1∶5万比例尺DEM地形信息容量对比 总被引：24，自引：1，他引：24
黄土丘陵沟壑区地形变化异常复杂，1：5万地形图对原始1：1万地形图等高线形态综合、取舍程度很大，这些都在不同程度上影响了地形分析结果的准确性。以高精度的1：1万比例尺DEM为校准植，运用1：1万及1：5万比例尺DEM叠合比较分析的方法，研究1：5万DEM的地形信息容量及提取不同地形要素的精度。试验结果表明，在黄土丘陵区，与1：1万DEM相比，1：5万DEM在所提取的地面坡度、地面曲率、沟壑量等地形定量指标方面均都存在着较大的误差。 相似文献
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Topography, as captured by a digital elevation model (DEM), can be used to model soil moisture conditions because water tends to flow and accumulate in response to gradients in gravitational potential energy. A widely used topographic index, the soil wetness index (SWI), was compared with a new algorithm that produces a cartographic depth-to-water (DTW) index based on distance to surface water and slope. Both models reflect the tendency for soil to be saturated. A 1 m resolution Light Detection and Ranging (LiDAR) DEM and a 10 m conventional photogrammetric DEM were used and results were compared with field-mapped wet soil areas for a 193 ha watershed in Alberta, Canada, for verification. The DTW model was closer to field-mapped conditions. Values of Kmatch90 (areal correspondence, smaller values indicating better performance) were 7.8% and 12.3% for the LiDAR and conventional DEM DTW models, respectively, and 88.5% and 86.7% for the SWI models. The two indices were poorly correlated spatially. Both DEMs were found to be useful for modelling soil moisture conditions using the DTW model, but the LiDAR DEM produced the better results. All major wet areas and flow connectivity were reproduced and a threshold value of 1.5 m DTW accounted for 71% of the observed wet areas. The poor performance of the SWI model is probably because of its over-dependence on flow accumulation. Incorporation of a flow accumulation algorithm that replicates the effects of dispersed flow showed some improvement in the SWI model for the conventional DEM but it still failed to replicate the full areal extent of wet areas. Local downslope topography and hydrologic conditions seemed to be more important in determining soil moisture conditions than is taken account of by the SWI. The DTW model has potential for application in distributed hydrologic modelling, precision forestry and agriculture and implementation of environmental soil management practices. 相似文献
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以数字地图为基础,以日本早池峰山地域为研究对象,研究不同地表拟合方法及DEM精度对坡度计算的影响:1)最小曲面法、逆距离法和剖面法3种不同的地表拟合方法对基于DEM计算的坡度影响很小。2)DEM精度对基于其计算的坡度有相当大的影响,随着DEM精度的降低,计算出的平均坡度变小。3)DEM精度对不同坡度级别有着不同的影响。这种影响按坡度大致可以分为3种类型:当坡度为0°～10°时,采用低精度的DEM将低估测面坡度,使这一坡度级面积增加;当坡度为10°～35°时,采用低精度的DEM将过高地估侧地面坡度,使这一坡度级面积减少;当坡度大于35°时,DEM精度对坡度的影响很小,坡度的频率分布随着DEM精度变化基本维持不变。 相似文献
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基于DEM的坡度研究--现状与展望 总被引：1，自引：2，他引：1
坡度是最基本的地貌形态指标,它对地表物质能量迁移转换具有重要影响。阐述了坡度研究的几个主要方面,包括坡度分级与坡度制图方法,DEM建立方法和DEM类型对坡度的影响,DEM分辨率对坡度的影响,坡度衰减和坡度变换研究等。指出传统坡度研究方法已与GIS的发展,DEM的广泛应用不相适应,也不能满足水文和土壤侵蚀定量模拟研究的需要。指出应从改善DEM质量和DEM对地形描述能力入手,将DEM及其基础上提取的坡度视为空间上连续变化的表面,引入数字图形图像处理方法,以区域尺度径流与土壤侵蚀模拟及其相关的数字地形分析为服务对象,对坡度问题展开系统研究。研究重点应包括:DEM类型对于坡度的影响,坡度衰减原理,坡度变换方法与变换结果应用等。 相似文献
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基于GIS的黄土高塬沟壑区砚瓦川流域地形特征提取与分析 总被引：1，自引：0，他引：1
以GIS技术为依托,研究了典型高塬沟壑区砚瓦川流域的地形分布特征.以1:5万地形图作为信息源,矢量化等高线,并用Hutchinson方法建立DEM(ANUDEM).从DEM中提取了坡度、剖面曲率和坡长三个地形因子,并对其特征进行了分析,同时与丘陵沟壑区相应地形因子特征进行了对比.结果显示:流域50%的面积坡度在9°以下、剖面曲率小于7,这反映出高塬沟壑区地面比较平坦的地形特点.坡长分布主要集中在10～150 m,其中10 m坡长分布最广.这些地形特征信息为砚瓦川流域及同类地区的生态建设与农业生产提供了有力的技术和基础数据支撑. 相似文献
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基于传统土壤图的土壤—环境关系获取及推理制图研究 总被引：3，自引：0，他引：3
在数字土壤制图研究中,从历史资料中提取准确的、详细的土壤—环境关系对于土壤图的更新和修正十分重要。从传统土壤图中提取土壤类型并从地形数据中提取环境参数,采用空间数据挖掘方法建立土壤—环境关系,并进行推理制图和精度验证。以湖北省黄冈市红安县华家河镇滠水河流域为例,首先选取成土母质和基于地形数据提取的高程、坡度、坡向等7个环境因子;然后利用频率分布原理得到包含土壤类型与环境因子信息的典型样本数据1 410个;采用See5.0决策树方法进行空间数据挖掘,建立土壤—环境关系;将其导入So LIM中进行推理制图;最后利用270个实地采样点验证所得土壤图的精度。土壤图的精度提高了约11%,证明了本研究方法对土壤类型和空间分布推理的可靠性。 相似文献
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基于中低分辨率的DEM提取地形湿度指数,对于区域土壤侵蚀因子和区域土壤侵蚀模型等研究有着重要的意义.但随着DEM分辨率的降低,坡度趋于平缓,单元栅格高程信息的改变也会影响单元汇流面积的计算,基于中低分辨率提取地形湿度指数必须考虑这两方面的影响.以1:5万数字地形图分别构TIN得到分辨率为10,20,40和60 m的DEM,进行频率和累计频率统计,以10 m分辨率DEM为参考对其它分辨率DEM做坡度变换,提出根据高分辨率DEM若干栅格的单元汇流面积的均值作为低分辨率DEM的单元汇流面积,根据这两方面对地形湿度指数进行了改正. 相似文献
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《CATENA》2004,55(3):255-276
The development of soil conservation plans and evaluation of spatially distributed erosion models require knowledge of rates of soil loss and sedimentation on different landscape elements and slope positions. Characterization of soil erosion rates and patterns within watersheds is important for the understanding of erosion processes and landscape evolution. Experimental data that show spatial translocation of soil on slopes are limited. A method for obtaining spatially distributed information on sediment movement employing rare earth element (REE) oxides is proposed. Five REE oxides in powder form were uniformly mixed with the soil on different parts of a 10% slope in a 4×4 m soil bed. Particle translocation was measured during eight simulated rainfalls at 60 mm h−1 intensity. A laser scanner was utilized to obtain digital elevation models (DEMs) of the soil surface that were used as the reference data to compare with the tracer method. REE concentration in soil and runoff samples was determined by inductively coupled plasma mass spectrometry (ICP-MS). Erosion rates for different slope positions estimated from REE concentrations correlated with those calculated from the DEMs with relative differences for different slope sections of 4–40%. The enrichment ratio for this type of tracer was 1.7. The amount of sediment produced on different parts of the slope varied, with the greatest erosion occurring on the upper-middle part of the slope. The experiment showed that the multi-element tracer method provided a satisfactory way to study soil erosion distribution on a uniform slope. 相似文献