Remote sensing-derived national land cover land use maps: a comparison for Malawi

Reliable land cover land use (LCLU) information, and change over time, is important for Green House Gas (GHG) reporting for climate change documentation. Four different organizations have independently created LCLU maps from 2010 satellite imagery for Malawi for GHG reporting. This analysis compares the procedures and results for those four activities. Four different classification methods were employed; traditional visual interpretation, segmentation and visual labelling, digital clustering with visual identification and supervised signature extraction with application of a decision rule followed by analyst editing. One effort did not report classification accuracy and the other three had very similar and excellent overall thematic accuracies ranging from 85 to 89%. However, despite these high thematic accuracies there were very significant differences in results. National percentages for forest ranged from 18.2 to 28.7% and cropland from 40.5 to 53.7%. These significant differences are concerns for both remote-sensing scientists and decision-makers in Malawi.     

第三次全国国土调查工作图斑地类常见认定问题分析

第三次全国国土调查已于2019年全面开展,图斑地类认定是该项工作的重点和难点。本文根据笔者所在单位在华南地区多个项目的实施经验,针对动土、建设用地和闲置用地3类重点图斑中常见的容易判断错误的问题,通过影像图、现场照片对比及国家发布的认定依据进行分析,总结了一套地类认定的规律和经验,有助于三调工作中快速、准确地认定地类,避免了返工和数据库的反复修改,从而可提高作业队伍在三调工作中的工作效率和工作质量。     

Potential of Landsat-8 and Sentinel-2A composite for land use land cover analysis

Abstract

This study proposes the development of a multi-sensor, multi-spectral composite from Landsat-8 and Sentinel-2A imagery referred to as ‘LSC’ for land use land cover (LULC) characterisation and compared with respect to the hyperspectral imagery of the EO1: Hyperion sensor. A three-stage evaluation was implemented based on the similarity observed in the spectral response, supervised classification results and endmember abundance information obtained using linear spectral unmixing. The study was conducted for two areas located around Dhundi and Rohtak in Himachal Pradesh and Haryana, respectively. According to the analysis of the spectral reflectance curves, the spectral response of the LSC is capable of identifying major LULC classes. The kappa accuracy of 0.85 and 0.66 was observed for the classification results from LSC and Hyperion data for Dhundi and Rohtak datasets, respectively. The coefficient of determination was found to be above 0.9 for the LULC classes in both the datasets as compared to Hyperion, indicating a good agreement. Thus, these three-stage results indicated the significant potential of a composite derived from freely available multi-sensor multi-spectral imagery as an alternative to hyperspectral imagery for LULC studies.     

基于地表覆盖/土地利用数据的沁河源区生态保护红线边界处理

边界处理是指借助地理信息系统软件,将生态保护红线从栅格形式的生态评估结果落实到具有明确边界的地块上,也称为红线的“落图”过程,是生态保护红线划定的重要流程,也是红线精准落地和有效管控的必要条件。本文以沁河源区为例,利用地理信息系统软件,基于地表覆盖、土地利用两种数据分别对生态功能极重要区红线进行落图。结果表明：两种数据均适用于红线边界处理,并且联合应用时处理结果更佳;沁河源区生态功能极重要区栅格面积为877.87 km²,联合应用两种数据处理后的红线矢量面积为877.73 km²,占研究区总面积的64.51%;研究结果可为生态功能重要区域生态保护红线边界的优化、调整提供参考。     

土地调查线状地物与图斑逻辑一致性缺陷修正方法

土地调查数据中部分线状地物与图斑存在逻辑一致性缺陷,造成图斑地类面积计算错误。为解决上述问题,本文对土地调查数据线/面逻辑关系进行研究,归纳了线状地物跨越图斑的缺陷类型;并对其成因和影响进行分析,设计了一种通过增量更新进行缺陷修正的方法。该方法不影响地类流量分析,能够较好地维护年度间统计结果的一致性,易于实现缺陷修正的自动化处理,并利于数据回溯。通过土地变更调查国家级数据库质量检查工作实践表明,本文提出的方法有助于提升数据检查的效率,具有较好的实用价值。     

土地资源遥感应用研究进展

遥感数据与土地资源在时空特性方面具有高度的一致性,土地资源研究长期是遥感应用的主要领域之一。过去数十年来,国内外开展了大量的土地资源与环境遥感应用研究,遥感技术为土地资源研究提供了丰富的信息源和实现手段,拓展了土地资源的研究内容,强化了土地资源的研究程度。随着遥感技术的发展和应用研究的深入,针对日益多样化的实际需求,创新研究方法,加强与传统学科的有机结合,在提取系列化专题信息基础上,开展不同时空尺度的综合性分析与评估,切实满足全球变化研究和实现区域可持续发展的需要,仍然是土地资源遥感应用研究应该关注的主要发展方向。     

Analysis of coastal land use/land cover changes in the Indian Sunderbans using remotely sensed data

The world’s largest mangrove ecosystem, the Sunderbans is experiencing multidimensional threats of degradation. The present study was aimed to understand these problems and search for proper remedies by applying suitable remote sensing technologies. South-western parts of Indian Sunderbans Biosphere Reserve had been chosen for assessment of land use/land cover changes in between 1975 and 2006 by using multitemporal Landsat data. Results indicated considerable reduction of open mangrove stands and associated biodiversity mainly in the forest-habitation interference zones of Sunderbans. On the contrary, increase in the coverage of dense mangroves in the reserved forests had been observed indicating the existence of proper centralized management regimes. Overall, a cumulative loss of approximately 0.42% of its original mangrove cover in between 1975 and 2006 had been estimated for this part of the Sunderbans which was at parity with the findings of other studies in the Sunderbans or similar mangrove ecosystems of the tropics. Expansion of non agricultural lands in the last two decades was found to be related with the growth of new settlements, tourism infrastructure, and facilities. This transformation was attributed to the shifting of local peoples’ interest from traditional forestry and subsistence farming towards alternative occupations like shrimp culture, coastal tourism, and commercial fishing although environmentally hazardous livelihood activities like collection of prawn seeds along the riverbanks were still persistent.     

基于特征的时空数据模型用于地籍变更的探讨

传统的基于专题地理分层的GIS数据模型在数据组织 ,数据共享及复杂的空间分析方面存在明显的不足 ,认为发展新一代的基于特征的时空模型成为必然。本文结合实践中地籍变更的特点 ,提出了基于特征变化状态的时空数据模型。该模型保持了地理现象的完整性 ,实现了时空专题信息的有机集成 ,有利于发展复杂的面向目标的定向分析。     

第三次国土调查的图斑自动综合方法

从第三次国土调查数据库快速缩编派生出多尺度数据库,是地图制图的重要任务。本文针对大量图斑,首先通过研究图斑栅格综合,减少碎图斑数量;然后构建图斑语义邻近度模型、空间几何拓扑模型,分析了顾及拓扑和地区地理特征约束下的地类图斑制图综合方法;最后形成了自动化图斑缩编生产工艺流程。基于上述方法,采用计算机编程技术研发国土三调缩编系统,并应用于四川省某县23万图斑量的三调数据并试验验证。试验结果表明,通过本文方法的成果符合专题制图要求,极大地提高了三调图斑的自动综合效率。     

Study on applying optimal path to land valuation

As an important role in the urban land price system, the basic land price appraisal directs and reflects all kinds of land price in the real estate market. Using geographic information systems (GIS) with algorithms and powerful analysis functions to valuate land will improve the rationality and convenience of land valuation. The objective of the study on basic land price using the optimal path algorithm is to decrease the manmade error, enhance automatization, avoid make inconvenience by roadblock object.     

高铁大临设施用地复垦利用辅助系统的设计与实现

本文根据复垦利用流程及复垦业务功能需求,结合组件式GIS集成开发技术,基于VS2008与Arc En-gine平台,采用SQL Server 2005数据库设计并开发了高速铁路大临设施用地复垦利用辅助决策系统。该系统实现了复垦方向优化过程的自动分析、复垦利用参数的动态设定、复垦工程量及投资的自动计算,并在京沪高铁江阴制梁场得到应用,取得了良好的效果。     

Integrated application of RS and GIS to agriculture land use planning

This paper gives some guidelines of land use planning firstly. A framework of agriculture land use planning is designed based on land use suitability evaluation using integrated technologies of RS and GIS. Further work expected is also given.     

Integrated Application of RS and GIS to Agriculture Land Use Planning

This paper gives some guidelines of land use planning firstly.A framework of agriculture land use planning is designed based on land use suitability evaluation using integrated technologies of RS and GIS.Further work expected is also given.     

Study on applying optimal path to land valuation

Introduction Thebasiclandpriceistheaveragepriceofev eryequalparceloreverylandclassspecifiedby thegovernment,accordingtodifferentuseof landsuchascommerce,industry,residence,etc.Asanimportantroleplayingintheurban landpricesystem,thebasiclandpriceinstructs a…     

Stylized environments and ABMs: educational tools for examining the causes and consequences of land use/land cover change

A challenge in land change science is to assess the causes and consequences of LULC change and associated pattern–process relations. Increasingly, land change organizations are examining land use at local to global scales for historical, contemporary and future periods through scenarios that assess population–environment interactions. Spatial analytical tools in GIScience are being used to link people and environment and to search for the distal and proximate factors that affect local to global land use patterns. Spatial simulation models that rely upon complexity theory as the framework and agent-based models as the analytical approach offer the capability to inform through experimentation about land issues important to science and society. Using a stylized landscape where a selected set of key social, geographical and ecological elements are spatially organized, we describe how land dynamics can be examined through agent-based models as educational tools that are useful in the classroom, boardroom and public forums.     

安徽省含山县土地整理耕地质量评价及其变化研究

土地整理是改善土地利用条件,提高土地质量的有效措施,对土地整理后的耕地质量进行评价是土地整理重要工作之一。从耕地质量的内涵和土地整理项目的基本要求出发,选取耕地自然条件和耕地利用条件2个基本因素和12个影响因子,将特尔斐法与层次分析法相结合,确定各因子权重,构建基于土地整理的耕地质量评价指标体系。以安徽省含山县铜闸镇土地整理项目为例,采用传统的土壤调查与3S技术相结合的方法,分析土地整理复垦过程中耕地质量时空格局变化,得出整理前、后耕地质量的级别变化。研究结果表明,通过土地整理,研究区的耕地质量空间分布和级别发生了很大变化,整理后一级、二级、三级质量的土地比整理前分别增加了7.20%,11.95%和0.65%,四级、五级则分别减少了15.65%和4.16%,整理后的耕地质量总体水平是整理前的1.291倍。     

Discriminant analysis on land grading

This paper proposes the discriminant analysis on land grading after analyzing the common methods and discussing the Fisher‘s discriminant in detail. Actually this method deduces the dimension from multi to single, thus it makes the feature vectors in n-dimension change to a scalar, and use this scalar to classify samples. This paper illustrates the result by giving an example of the residential land grading by the discriminant analysis.     

基于遥感的蒸散与土地利用及主要地表参数的关系研究——以乌裕尔河下游为例

以TM/ETM+影像为数据源,利用自动分类与目视解译相结合的方法提取了研究区1992～2001年共5个时相的土地利用信息;采用SEBAL模型估算影像过境当天的日蒸散量;最后对蒸散与土地利用变化、植被覆盖度及地表温度等地表参数之间的关系进行了相关性分析。结果表明:水体、湿地具有较高的日蒸散量,草地、旱地、林地次之,盐碱地、居民地最低。说明蒸散与地表温度、植被覆盖度等密切相关,土地利用变化是引起上述变化的主要驱动力之一。     

MODIS数据的水浇地提取

水浇地是土地覆盖分类系统中的一个重要类型, 依据水分亏缺指数(WDI)与土壤水分的相关性, 计算了监测时间内WDI的变化情况, 用降雨资料去除了由于降雨引起的WDI的变化, 进而提取了研究区的水浇地分布。结果表明：(1)提取出的水浇地在数量上与统计资料相比, 除山西省偏差相对较大外, 其余各省偏差均小于7%, 提取出的结果与统计资料具有可比性。(2)提取出的水浇地在空间上多成片出现在河流、湖泊、水库附近、灌区和绿洲上, 与已知的水浇地集中区一致。(3)利用TM影像对提取结果进行了初步判断, 其中山西省的正确率较低, 只有64%, 其余各省正确率均在70%以上, 新疆的正确率最高为92%。     

二轨法DInSAR技术监测城市地表沉降

合成孔径雷达差分干涉测量技术是新近发展起来的用于监测大范围地表形变的新技术,具有精度高、监测范围广等特点。文中深入分析DInSAR技术的基本原理,通过实验成功获取西安市中心城区相隔9个月的地面沉降结果,与常规方法获取的沉降图对比,发现二者具有高度的一致性,从而证明利用DInSAR技术监测城市地面沉降具有良好的应用前景。