Ajax在星级评分系统中的应用

在Web应用程序中利用Ajax技术可以实现页面的局部刷新，客户端用户不会感觉到有网页提交或刷新的过程，Web页面也不需要被重新加载，这种方式能使用户得到丰富的应用体验。本文通过网站星级评分系统的实现来学习和和讨论Ajax技术在Web中的应用。     

数字土壤制图技术研究进展与展望

土壤调查与制图是获取土壤信息的基本手段,在土壤科学发展中发挥了至关重要的作用,采用新方法开展数字土壤制图是土壤学科新兴的研究方向。本文全面回顾总结了近年来国内外数字土壤制图工作开展情况、方法的发展和应用,分析了当前在数字土壤制图研究中存在的主要问题,并且对数字土壤制图研究的发展趋势进行了展望,提出了今后一段时间我国开展这方面工作的建议,可以为数字土壤制图研究工作提供参考。     

新时代土壤地理学的发展现状与趋势

土壤地理学是研究土壤时空分布规律、形成过程及其资源环境效应的土壤学学科分支，其主要目标和任务是理解土壤形成演化的关键过程与影响因素并预测未来土壤-环境的共同演化特征，揭示土壤资源分布规律、利用前景和保护对策，为农业、生态环境保护等提供科学依据，支撑土壤普查、耕地保护等国家目标。21世纪特别是新时代10年以来土壤地理学取得了一些重要的进展，研究对象和内容也发生了很大的变化，逐渐向以土壤为核心的地球表层系统科学发展，高强度人为活动和全球气候变化背景下的土壤时空演变研究愈加活跃。土壤地理学主要发展趋势包括土壤信息获取方式正在发生变革，数字土壤制图向融合过程机理与数据驱动发展，土壤时空信息的应用范围更加广泛。未来土壤地理学优先发展领域包括：以关键带研究带动土壤发生和演变研究的革新，基于多传感器的土壤综合观测原理与技术，多尺度数字土壤制图与时空变化预测等。     

基于数据库驱动技术的土壤图注记自动配置系统的设计与实现

土壤注记是土壤图制图表达的重要内容,对于理解土壤的发生、分布具有重要意义。在基于全国第二次土壤普查资料进行大比例尺土壤图分幅制图过程中,若对拥有海量土壤空间信息的多分幅大比例尺土壤图实现注记表达,不可能再依赖于传统的制图方式生成注记。为了实现注记上图的自动化和以交互方式解决多个步骤判断问题,构建了土壤图注记自动配置系统。该系统采用图廓边界注记压盖检测与处理技术,解决了注记压盖图廓边界的问题;采用图层、分级码、要素对象的三级控制方法,实现了注记在图层级别上进行整个图层以及背景层注记的设置,在分级码级别上结合统计结果,实现了注记的条件判别与阈值过滤,在要素级别上实现了特殊要素注记的生成。基于数据库驱动技术并以人机交互的方式进行土壤图注记的自动化配置,实现了批量土壤图分幅注记的快速生成,不仅具有较强的灵活性,可适用于不同比例尺土壤图及其他类型地图的注记表达,而且大大提高了数据生产的效率和自动化处理程度。该研究为今后不同比例尺土壤图制图实现注记的自动化配置提供参考。     

土壤质量数字制图方法浅论

本文简要论述了土壤质量数字制图的一般过程及其与传统土壤制图的异同,并依据土壤制图原理确定数字制图的几个重要参数,同时简述了数字制图对野外土壤调查的要求以及对传统图件的处理。     

县域土壤质量数字制图方法比较

土壤质量研究几乎涵盖土壤研究的所有领域,土壤质量制图理论与方法是土壤质量研究的一项重要研究内容。该研究以北京市密云县为研究区,基于土壤质量评价最小数据集和指数和法计算的土壤质量指数,探究了在地学模型支持下区域土壤质量数字制图方法。研究设计了5种区域土壤质量数字制图方法,并比较了不同方法的空间数字制图精度。结果显示,目前广泛使用的基于参评指标空间插值结果的土壤质量数字制图方法精度最低、工序较繁琐,且无法反映研究区景观高度异质的特点;而基于计算后的土壤质量指数（soil quality index,SQI）,借助于地统计学方法的土壤质量数字制图方法相对比较科学合理,其中又以基于计算后的SQI和回归克里格法预测效果最好,均方根误差最小,仅为0.01897,相对于基于参评指标空间插值结果的土壤质量数字制图方法,精度相对提高率最大,达到50%以上。综合考虑空间制图精度、工序的繁简程度,在该研究设计的5种方法中基于计算的SQI和回归克里格法最佳,该法避免了地统计插值在景观高度异质区的应用局限性,预测结果与实际最为相符。     

基于GIS的中国土壤分类专家系统设计

土壤系统分类以定量化指标划分土壤类型,为土壤自动分类系统的建立提供了依据;地理信息系统(CIS)的应用扩展了土壤空间信息表达的能力,为实现土壤分类自动制图提供了手段。本文着重模仿专家的思维过程,探讨如何实现土壤自动分类。(1)采用面向对象的方法表达专家经验规则、诊断层和诊断特性知识,并在此基础上提出了决策树的构造方式和推理方法;(2)从土壤系统分类专家的知识表示和推理机的构建两个方面,提出了土壤分类专家系统(SCES)的体系结构、土壤自动分类与地理信息融合的方法和基于GIS和专家系统(ES)的土壤自动分类检索系统的框架结构。     

应用模糊c均值聚类获取土壤制图所需土壤-环境关系知识的方法研究

在没有土壤普查专家及土壤图的地区,获取土壤环境间关系的知识是基于知识进行预测性土壤制图中的关键问题。本文建立了一套应用模糊c均值聚类(Fuzzyc-means,FCM)获取土壤环境间关系知识的方法:得到对土壤形成发展具有重要作用的环境因子,建立环境因子数据库;对环境因子进行模糊聚类,得到环境因子组合隶属度分布图;根据隶属度值确定野外采样点;将环境因子组合与土壤类型对应,进而提取土壤-环境关系知识。为检验该方法的有效性,应用所得知识进行土壤制图,通过独立采样点对土壤图进行精度评价。本文在黑龙江鹤山农场一个研究区的应用结果表明,该方法仅需要少量的野外采样即可获得有效的土壤-环境关系知识,为预测性土壤制图提供必需的依据,同时也显著提高了野外采样的效率。     

区域微机土壤信息系统的建立与应用

我们用FORTRAN语言和DBASE-1V作为主要支撑软件，在IBH-PC-XT机上建立了区域微机土壤信息系统。系统软件的工作方式是高级语言和数据库的通讯。该系统通过三级功能菜单完成全部系统功能，主要有：1.建立RSIS数据库;2.建立数字地形模型；3.土壤数据库管理；4.统计分析；5.制图与报表；6.信息提取、分析与复合；7.土壤与非土壤信息的合与评价。我们在吉林农安县对该系统进行了试验，取得了满意的结果。     

小麦、玉米、水稻施肥模型的建立

采用系统研究法在河北省玉田县进行施肥推荐的田间试验和示范,根据19921993年的试验和示范结果,建立包括土壤测试值、施肥量和若干虚似变量为自变量的小麦、玉米、水稻施肥模型,编写了在EXCAL软件上的应用程序,为模型的应用创造了条件。     

Small scale digital soil mapping in Southeastern Kenya

Digital soil mapping techniques appear to be an interesting alternative for traditional soil survey techniques. However, most applications deal with (semi-)detailed soil surveys where soil variability is determined by a limited number of soil forming factors. The question that remains is whether digital soil mapping techniques are equally suitable for exploratory or reconnaissance soil surveys in more extensive areas with limited data availability. We applied digital soil mapping in a 13,500 km² study area in Kenya with the main aim to create a reconnaissance soil map to assess clay and soil organic carbon contents in terraced maize fields. Soil spatial variability prediction was based on environmental correlation using the concepts of the soil forming factors equation. During field work, 95 composite soil samples were collected. Auxiliary spatially exhaustive data provided insight on the spatial variation of climate, land cover, topography and parent material. The final digital soil maps were elaborated using regression kriging. The variance explained by the regression kriging models was estimated as 13% and 37% for soil organic carbon and clay respectively. These results were confirmed by cross-validation and provide a significant improvement compared to the existing soil survey.     

一种基于样点代表性等级的土壤采样设计方法

采样设计是获取土壤空间分布信息的关键环节,直接影响到土壤制图的精度。目前常用的采样设计方法大多存在着设计样本量大、采样效率不高的问题。当可投入资源难以完成一次性大量采样时,采样往往需要多次、分批进行。然而现有分批采样方法多考虑各批采样点在地理空间的互补性,可能造成样本点在属性空间的重叠,影响采样资源的高效利用。鉴于此,本研究通过对与土壤在空间分布具有协同变化的环境因子进行聚类分析,寻找可代表土壤性状空间分布的不同等级类型的代表性样点,建立一套基于代表性等级的采样设计方法。将该采样方法应用于位于黑龙江省嫩江县鹤山农场的研究区,利用所采集的不同代表性等级的样点进行数字土壤制图并进行验证,探讨采样方案与数字土壤制图精度的关系,以评价本文所提出的采样方法。结果表明,通过代表性等级最高的少量样点可获取研究区的大部分主要土壤类型(中国土壤系统分类的亚类级别),且制图精度较高;随着代表性等级较低样点的加入,土壤图精度提高;但当样点增加到一定数量时,土壤图的精度变化不大。因此,与样点数相比,样点的代表性高低对制图精度的影响更大。该方法所提出的代表性等级可以为样点采集顺序提供参考,有助于设计高效的逐步采样方案。     

Spatial aggregation of soil property predictions in support of local land management

Over the past decades, numerous practical applications of Digital Soil Mapping have emerged to respond to the need of land managers. One important contribution to this effort is the release of regional‐scale soil maps from the GlobalSoilMap (GSM) project. While the GSM project aims at producing soil property predictions on a fine 90 × 90 m grid at the global scale, land managers often require aggregated information over larger areas of interest (e.g. farms, watersheds, municipalities). This study evaluated a geostatistical procedure aiming at aggregating GSM grids to a land management scale, thereby providing land suitability maps with associated uncertainty for the French region ‘Languedoc‐Roussillon’ (27 236 km²). Specifically, maps were derived from three GSM prediction grids (pH, organic carbon and clay content) by calculating the proportion of ‘suitable’ agricultural land within a municipality, where suitability was defined as having soil property values below or above a predefined threshold (pH < 5.5, OC < 10 g/kg, clay > 375 g/kg). Calculation of these nonlinear spatial aggregates and the associated uncertainty involved a three‐step approach: (i) sampling from the conditional probability distributions of the soil properties at all grid cells by means of sequential Gaussian simulation applied to a regression kriging model, (ii) transformation of soil properties to suitability indicators for all grid cell samples generated in the first step and (iii) spatial aggregation of the suitability indicators from grid cells to municipalities. The maps produced show large differences between municipality areas for all three land suitability indicators. The uncertainties associated with the aggregated suitability indicators were moderate. This approach demonstrated that fine‐scale GSM products may also fulfil user demands at coarser land management scales, without jeopardizing uncertainty quantification requirements.     

关于我国“数字土壤”建设若干问题的思考

对"数字土壤"的渊源、定义、功能以及如何建设我国的"数字土壤"进行了讨论。"数字土壤"渊源于"数字地球",是土壤学科发展的产物、是土壤科学与现代信息技术和计算机技术相融合的必然趋势,是一种进行土壤科学研究的现代技术体系;"数字土壤"具有管理与提供土壤科学数据、进行空间分析、制作士壤专题图、指导土壤调查、查询与传播土壤信息、构建运用模型、土壤质量预警等功能;历史土壤调查资料是研制我国"数字土壤"的骨干材料;中国需要同时研制不同精度的"数字土壤";"联合共建",是建设我国"数字土壤"的好途径。     

Scanning Mode Application of Neutron-Gamma Analysis for Soil Carbon Mapping

Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. Applications of neutron-gamma analysis in scanning mode for mapping of soil carbon are discussed. A Global Positioning System(GPS) device and softwares required to simultaneously acquire gamma signals and geographical positions during scanning operations were added to an existing measurement system. The reliability of soil carbon measurements in scanning mode was demonstrated to be in agreement with results acquired from static mode. The error analysis indicated that scanning measurements can be conducted with the same accuracy as static measurements in approximately one fourth the time. To obtain results suitable for mapping analogous to traditional chemical analyses(i.e., ± 0.5 in weight percent or ± 0.5 w%), scanning time over a given site should be ca. 15 min using the current measurement system configuration. Based on this measurement time, a reasonable towing speed of 3–5 km h-1, the necessity for complete site coverage during scanning, the number of sites(within the surveyed field), and the required total measurement time can be estimated. Soil carbon measurements for 28 field sites(total area ca. 2.5 ha) were conducted in ca. 8 h. Based on acquired data,a soil carbon distribution map was constructed utilizing various softwares. The surveyed field area included an asphalt road that had carbon readings higher than the surrounding land. The clarity with which these carbon-rich zones were delineated on the constructed map represents evidence supporting the veracity of this method. Neutron-gamma analysis technology can greatly facilitate timely construction of soil carbon maps.     

Digital soil mapping in Germany—a review

Digital soil mapping as a tool to generate spatial soil information provides solutions for the growing demand for high‐resolution soil maps worldwide. Even in highly developed countries like Germany, digital soil mapping becomes essential due to the decreasing, time‐consuming, and expensive field surveys which are no longer affordable by the soil surveys of the individual federal states. This article summarizes the present state of soil survey in Germany in terms of digitally available soil data, applied digital soil mapping, and research in the broader field of pedometrics and discusses future perspectives. Based on the geomorphologic conditions in Germany, relief is a major driving force in soil genesis. This is expressed by the digital–soil mapping research which highlights the great importance of digital terrain attributes in combination with information on parent material in soil prediction. An example of digital soil mapping using classification trees in Thuringia is given as an introduction in digital soil‐class mapping based on correlations to environmental covariates within the scope of the German classification system.     

Proximal sensor-enhanced soil mapping in complex soil-landscape areas of Brazil

Portable X-ray fluorescence (pXRF) spectrometry and magnetic susceptibility (MS) via magnetometer have been increasingly used with terrain variables for digital soil mapping. However, this methodology is still emerging in many countries with tropical soils. The objective of this study was to use proximal soil sensor data associated with terrain variables at varying spatial resolutions to predict soil classes using the Random Forest (RF) algorithm. The study was conducted on a 316-ha area featuring highly variable soil classes and complex soil-landscape relationships in Minas Gerais State, Brazil. The overall accuracy and Kappa index were evaluated using soils that were classified at 118 sites, with 90 being used for modeling and 28 for validation. Digital elevation models (DEMs) were created at 5-, 10-, 20-, and 30-m resolutions using contour lines from two sources. The resulting DEMs were processed to generate 12 terrain variables. Total Fe, Ti, and SiO₂ contents were obtained using pXRF, with MS determined via a magnetometer. Soil class prediction was performed using the RF algorithm. The quality of the soil maps improved when using only the five most important covariates and combining proximal sensor data with terrain variables at different spatial resolutions. The finest spatial resolution did not always provide the most accurate maps. The high soil complexity in the area prevented highly accurate predictions. The most important variables influencing the soil mapping were MS, Fe, and Ti. Proximal sensor data associated with terrain information were successfully used to map Brazilian soils at variable spatial resolutions.     

浙江省土壤发生分类与系统分类参比及制图研究

利用新建立的浙江省1∶5万土壤数据库,对土壤发生分类土种与中国土壤系统分类亚类进行了参比,编制了土壤系统分类亚类分布图.结果表明,发生分类基层分类单元归属较为清楚,但高级单元关系较为复杂.99个土属有62个参比归属唯一,277个土种有252个参比归属唯一,通过参比将大比例尺土壤普查成果转换成系统分类体系是可行的,可以满足1∶10万的系统分类亚类制图要求.浙江省土壤参比后归属于8个土纲,以雏形土土纲面积最大,占总面积的31.3％;人为土次之,占总面积的21.4％,有机土面积最小.在系统分类土纲层次,土壤区域分布规律较为明显.研究结果对指导土壤系统分类具有一定的参考价值,也为省域范围的系统分类制图提供了范例.