Predicting salinity impacts of land-use change: Groundwater modelling with airborne electromagnetics and field data,SE Queensland,Australia

Throughout Australia, there is concern that land use change is mobilizing salt stored in the landscape, causing salinity in soil and water resources. Salt in the landscape becomes a salinity risk only if it is mobilized by groundwater movement. A combination of modelled groundwater behaviour under various land uses with three-dimensional salt-load maps developed from airborne electromagnetic survey (AEM) provides a practical tool to assess potential salt movement.AEM survey of the country around St. George, SE Queensland, revealed a potential salinity threat: significant salt stores in the uplands adjacent to flood plains which support important irrigation developments and which drain to the Darling River system. A conceptual model of the regional hydrogeology was built upon three-dimensional AEM data, an investigation-drilling program, and direct field measurement of hydraulic conductivities. This information was incorporated in a Flowtube groundwater model and groundwater responses to five different land management options were tested over a 100-year period. Surface water storage on relatively permeable soils and continuous irrigated cotton both resulted in water tables reaching the soil surface; rain-fed wheat and pasture both resulted in a raised watertable, but both established a new equilibrium without the water table reaching the ground surface.     

Environmental geophysics mapping salinity and water resources

Salinity and fresh water are two sides of the same coin, most conveniently measured by electrical conductivity; they can now be mapped rapidly in three dimensions using airborne electromagnetics (AEM). Recent developments in the calibration of airborne data against in-field measurements and additional information from radiometrics, magnetics and digital elevation models lend new insights into salinity, groundwater flow systems and water resources. Freshwater resources can be mapped, and salinity risk and the outcome of management interventions may be forecast, on the basis of the specific architecture of complete groundwater flow systems-enabling practical, cost-effective protection and development of water resources.     

Three-dimensional mapping of salt stores in the Murray-Darling Basin,Australia: 2. Calculating landscape salt loads from airborne electromagnetic and laboratory data

Salt is widespread in the Australian landscape – in soil, regolith and groundwater – leading to concerns that land management practices may be putting much agricultural land and important water resources at risk of salinisation. Defining the location and nature of salt stores is an important first step in understanding the processes leading to salinity of soils, streams and groundwater resources, and predicting areas that may be at risk. Airborne geophysics can define subsurface salt stores and mobilisation pathways. Airborne electromagnetics (AEM) can map the three-dimensional conductivity structure of the landscape but does not, intrinsically, quantify the amount of salt. Salinity, moisture content, porosity and mineralogy all contribute to the electromagnetic signal, and each can vary significantly throughout the landscape.In the Lower Balonne catchment, Queensland, the relationship between AEM and the amount of salt in the landscape was quantified using laboratory analyses of pore fluids from core samples. A general statistical relationship was established between AEM conductivity and salt load (defined as the product of pore fluid salinity, porosity and moisture content)—with a significant positive correlation although data were generally widely dispersed. Comparison of calculated salt load with borehole electromagnetic logs gives insight into the factors contributing to dispersion in the AEM data.The relationship transforms bulk conductivity to salt load in 5 m layers, allowing the generation of a three-dimensional map of the salt load. This is a powerful tool for identifying areas that may require monitoring and management interventions to reduce salinity risk. An example is given of salt loads beneath an established irrigation area in the Lower Balonne catchment, Queensland.     

空间辅助决策支持系统的应用模型及管理研究

应用建模是空间辅助决策支持系统有效管理和使用模型的基础。本文抽象了空间辅助决策应用模型的组成结构和建立过程,分析了空间辅助决策应用模型的特点;接着分基础空间模型库、基础非空间模型库、应用模型库、模型管理库四部分探讨了空间决策支持系统中应用模型的管理,最后给出了相应的建设性结果。     

新时代下陕西测绘地理信息服务自然资源管理的思考与实践

针对机构改革及自然资源部职责分工,客观分析了新时代下我国自然资源的管理现状及存在问题。陕西测绘地理信息局基于技术沉淀优势并围绕职责定位,从测绘基准体系服务、标准框架分析建设、时空大数据资源整合、体系架构设计验证及平台服务政府决策等多项实际出发,展开了新时代新机构新职责下陕西测绘地理信息服务自然资源管理的思考分析和初步实践;同时,基于混合存储环境及云平台体系架构,选用范围近2 800 000 km²的数据开展影像处理、DEM/DOM/DSM产品制作、超2100个全国基准站网GNSS数据解算等试验测试,发现架构体系合理,项目生产及存储效率均有大幅提升,这为外派机构及行业单位实施类似项目提供了示范参考,也为陕西测绘地理信息局充分发挥"技术+数据"优势、更好地服务自然资源管理大局奠定了良好基础。     

自然资源管理中权属界线与空间管控界线测绘精度的问题分析

自然资源权属界线、空间管控界线作为自然资源产权管理与国土空间用途管制的重要依据,不仅是技术线,更是政策线。机构改革前界线测绘工作由相关部门分头管理,界线落地时出现了空间范围不准、空间交叉冲突等问题。本文从自然资源管理中空间管控界线、权属界线两类界线测绘的统筹管理需求出发,对提高界线测绘精度、完善界线测绘制图标准等有关问题进行了探讨。     

Assessing the accuracy of hyperspectral and multispectral satellite imagery for categorical and Quantitative mapping of salinity stress in sugarcane fields

This study evaluates the feasibility of hyperspectral and multispectral satellite imagery for categorical and quantitative mapping of salinity stress in sugarcane fields located in the southwest of Iran. For this purpose a Hyperion image acquired on September 2, 2010 and a Landsat7 ETM+ image acquired on September 7, 2010 were used as hyperspectral and multispectral satellite imagery. Field data including soil salinity in the sugarcane root zone was collected at 191 locations in 25 fields during September 2010. In the first section of the paper, based on the yield potential of sugarcane as influenced by different soil salinity levels provided by FAO, soil salinity was classified into three classes, low salinity (1.7–3.4 dS/m), moderate salinity (3.5–5.9 dS/m) and high salinity (6–9.5) by applying different classification methods including Support Vector Machine (SVM), Spectral Angle Mapper (SAM), Minimum Distance (MD) and Maximum Likelihood (ML) on Hyperion and Landsat images. In the second part of the paper the performance of nine vegetation indices (eight indices from literature and a new developed index in this study) extracted from Hyperion and Landsat data was evaluated for quantitative mapping of salinity stress. The experimental results indicated that for categorical classification of salinity stress, Landsat data resulted in a higher overall accuracy (OA) and Kappa coefficient (KC) than Hyperion, of which the MD classifier using all bands or PCA (1–5) as an input performed best with an overall accuracy and kappa coefficient of 84.84% and 0.77 respectively. Vice versa for the quantitative estimation of salinity stress, Hyperion outperformed Landsat. In this case, the salinity and water stress index (SWSI) has the best prediction of salinity stress with an R² of 0.68 and RMSE of 1.15 dS/m for Hyperion followed by Landsat data with an R² and RMSE of 0.56 and 1.75 dS/m respectively. It was concluded that categorical mapping of salinity stress is the best option for monitoring agricultural fields and for this purpose Landsat data are most suitable.     

新一代三维GIS在自然资源与不动产信息管理中的应用

自然资源部要实现山、水、林、田、湖、草等自然资源与不动产登记的一体化管理,必须统筹考虑自然生态各要素、山上山下、地上地下、陆地海洋及流域上下游,实现国土空间中各类自然资源与不动产登记数据的融合衔接。但是传统二维GIS在全要素信息表达、多类型资源拓扑表达及资源资产监管分析等方面都存在不可避免的短板。为弥补二维GIS的不足,新一代三维GIS技术体系逐渐形成,包括能够全空间表达自然资源与不动产对象的数据模型,面向多尺度、多源、异构三维数据的融合技术,以及三维空间分析与计算技术,实现了对自然资源与不动产信息管理的全面升维。本文在新一代三维GIS技术的基础上,建立自然资源与不动产信息管理平台,以全新视角认知山水林田湖草生命共同体,提升自然资源与不动产管理系统的服务能力,实现自然资源和不动产信息的一体化管理、用途管制及辅助决策能力。     

渭南市旅游资源管理评价信息系统的设计与实现

旅游资源单体作为旅游资源普查的重要成果,具有数量多、分布广、资料丰富等特点。利用计算机对旅游资源普查成果资料进行集中管理、分析、评价,对旅游资源的合理规划利用和旅游业的跨越式发展具有重要意义。本研究以组件式地理信息系统软件为基础平台,以GIS技术、数据库技术和模块设计技术为基本技术支持,设计开发了渭南市旅游资源管理评价信息系统,对其需求分析、体系结构、数据库建设及功能实现进行了详细探讨。     

多维动态GIS在海岛保护与利用管理中的应用

针对海岛空间信息的特点,分析了传统管理手段的缺陷,提出了利用多维动态GIS技术解决海岛及其周边海域三维特性和数据多源、多尺度、多时相以及海岛的历史变迁问题,并探讨了应用的关键技术,为海岛综合管理提供一个新的解决方案,提高了海岛管理的可视化、信息化、高效化和科学化.     

多源空间信息集成技术在铁路用地信息管理中的应用

铁路信息化和数据标准化对铁路用地信息管理提出了更高的要求,多源空间信息集成技术是集成各种铁路空间数据、实现铁路用地信息化管理的基础。本文根据铁路用地空间数据的来源和组成,针对数据的多源、多尺度、动态等特点,提出了基于元数据驱动的铁路用地空间数据集成技术框架,设计了三层分布式C/S铁路用地信息系统结构,所构建的"武汉铁路局铁路用地综合信息管理系统"已取得理想的实际应用效果。     

面向电子政务的广播电视场强覆盖计算方法研究

本文就地理信息系统(GIS)在广播电视政务中的应用进行论述,通过分析GIS的优势与特点,阐述了基于GIS技术的广播电视场强覆盖计算方法,具有一定的现实意义。     

Implications of management strategies and vegetation change in the Mount St. Helens blast zone

The 1980 eruptions of Mount St. Helens provided an excellent opportunity for scientists to investigate the recovery of vegetation communities following a major geologic disturbance. An important and often overlooked aspect in these studies is the human factor in recovery processes, and specifically, the different management approaches taken towards re-establishment of vegetation on lands under the control of various owners. This study examines vegetation changes throughout the 1980 blast zone using a time series of Landsat-derived Normalized Difference Vegetation Index (NDVI) images and change detection methods to assess the changes over 25 years, from 1980 to 2005, as a function of human management combined with ecological factors. This long-term tracking of change indicates that differences in the speed of vegetation re-establishment and consequent rates of change substantially reflect human involvement and varying management strategies.     

Comparing the spectral settings of the new generation broad and narrow band sensors in estimating biomass of native grasses grown under different management practices

The challenge of assessing and monitoring the influence of rangeland management practices on grassland productivity has been hampered in southern Africa, due to the lack of cheap earth observation facilities. This study, therefore, sought to evaluate the capability of the newly launched Sentinel 2 multispectral imager (MSI) data, in relation to Hyperspectral infrared imager (HyspIRI) data in estimating grass biomass subjected to different management practices, namely, burning, mowing and fertilizer application. Using sparse partial least squares regression (SPLSR), results showed that HyspIRI data exhibited slightly higher grass biomass estimation accuracies (RMSE = 6.65 g/m², R² = 0.69) than Sentinel 2 MSI (RMSE = 6.79 g/m², R² = 0.58) across all rangeland management practices. Student t-test results then showed that Sentinel 2 MSI exhibited a comparable performance to HyspIRI in estimating the biomass of grasslands under burning, mowing and fertilizer application. In comparing the RMSEs derived using wave bands and vegetation indices of HyspIRI and Sentinel, no statistically significant differences were exhibited (α = 0.05). Sentinel (Bands 5, 6 and 7) and HyspIRI (Bands 730 nm, 740 nm, 750 nm, 710 nm), as well as their derived vegetation indices, yielded the highest predictive accuracies. These findings illustrate that the accuracy of Sentinel 2 MSI data in estimating grass biomass is acceptable when compared with HyspIRI. The findings of this work provide an insight into the prospects of large-scale grass biomass modeling and prediction, using cheap and readily available multispectral data.     

中国湖泊分布与变化：全国尺度遥感监测研究进展与新编目

湖泊提供重要的生产生活用水,在维系生态安全方面发挥显著的价值。中国地理环境复杂多样,湖泊类型各异,不同湖区间的湖泊时空变化特征及驱动机制复杂。两次全国湖泊调查是国家尺度的湖泊变化监测的开创性工作,近年来伴随遥感数据源的海量积累和湖泊遥感提取方法的快速发展,大尺度湖泊水体变化遥感监测研究取得了长足的发展。然而,由于人工判读、湖泊类型判别依据和遥感数据源时相的差异,湖泊水体遥感提取结果及面积估算存在不同程度的出入。首先,本文总结了现有全国尺度湖泊监测研究的遥感数据源、方法和结果,分析了不同研究分析结果差异的可能原因。其次,本文基于1980s—2010s时段Landsat影像制图的湖泊水淹频率数据集的最大水域范围信息,提取并生成了全国湖泊新编目,以其作为该时段内湖泊判定和水体变化监测空间约束的统一参照,避免了因遥感数据时相与年际、年内湖泊水域范围波动对遥感提取结果及湖泊面积计算带来的差异。最后,本文从湖泊水淹范围频度的统计角度,初次提出了可体现湖泊面积年内与年际变化情况的统计指标——概率等效面积,用于监测和指示湖泊水域动态。结果表明,近30年来,中国有3741个最大水域范围大于1 km²的湖泊,总面积约93723 km²,其中青藏高原湖区的湖泊数量约占全国三分之一,总面积超过了全国的一半。全国湖泊总面积呈显著上升趋势,不同湖区的变化趋势差异明显:青藏高原湖区和新疆湖区湖泊面积显著上升,东部平原湖区、内蒙古高原湖区和云贵高原湖区显著下降,东北平原与山地湖区波动式变化、趋势不显著。研究结果总体表明中国湖泊水资源的时空不平衡状况在加剧。