Mapping the Brazilian Amazon fluvial sensitivity index to oil spills with Shuttle Radar Topography Mission (SRTM) data

It is important to understand the Solimões River seasonal hydrological cycle and its dynamics to support systematic environmental monitoring efforts in the Amazon region. These are essential to the contingency response to possible accidents in the existing oil transportation network. This study seeks to map the environmental sensitivity to oil spills in the surroundings of Coari city, Amazonas State (AM). A computational method was employed representing the seasonal inundation phenomenon fluctuations, together with data from the Digital Elevation Model generated by the Shuttle Radar Topography Mission. These were matched with Coari fluviometric time series information and a Japanese Earth Resources Satellite-1 (JERS-1 SAR) geo-referenced mosaic of the Global Rain Forest Mapping Project. In this context, a mathematical morphology technique (watershed) integrated with all aforementioned data applying MatLab and ArcGIS computing resources generated results that enabled a better spatio-temporal understanding of the Amazon seasonal dynamics. Thus, the principal product of the research was the Coari fluvial oil spill sensitivity index map based on segmented inundation levels obtained with the proposed methodology.     

Assessment of Shuttle Radar Topography Mission Elevation Data Based on Topographic Maps in Turkey

Depending on scale, topographic maps depicting the shape of the land surfaces of the Earth are produced from different data sources. National topographic maps at a scale of 1:25 000 (25K maps) produced by General Command of Mapping are used as the base map set in Turkey. This map set, which consists of approximately 5500 sheets, covers the whole country and is produced using photogrammetric methods. Digital Elevation Models (DEMs) created from these maps are also available. Recently, another data source, Synthetic Aperture Radar (SAR) interferometric data, has become more important than those produced by conventional methods. The Shuttle Radar Topography Mission (SRTM) contains elevation data with 3 arc-second resolution and 16 m absolute height error (90 percent confidence level). These data are freely available via the Internet for approximately 80 percent of the Earth's land mass. In this study, SRTM DEM was compared with DEM derived from 25K topographic maps for different parts of Turkey. The study areas, each covering four neighboring 25K maps, and having an area of approximately 600 km², were chosen to represent various terrain characteristics. For the comparison, DEMs created from the 25K maps were obtained and organized as files for each map sheet in vector format, containing the digitized contour lines. From these data, DEMs in the resolution of 3 arc-second were created (25K-DEM), in the same structure as the SRTM DEM, allowing the 25K-DEMs and the SRTM DEM to be compared directly. The results show that the agreement of SRTM DEM to the 25K-DEM is within about 13 m, which is less than the SRTM's targeted error of 16 m. The spatial distribution of the height differences between SRTM-DEM and the 25K-DEM and correlation analysis show that the differences were mainly related to the topography of the test areas. In some areas, local height shifts were determined.     

Quantifying deforestation in the Brazilian Amazon using Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (ALOS PALSAR) and Shuttle Imaging Radar (SIR)-C data

The study examined the capability of dual-polarization SAR data for forest cover mapping and change assessment in the Brazilian Amazon Forest regions. Shuttle Imaging Radar (SIR)-C and Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (ALOS PALSAR) data were analysed to map and quantify deforestation. The images were classified using hybrid classifier, where each land cover was grouped in various spectral sub-classes interpreted on the imagery and later merged together to generate the desired land cover classes. The classification accuracy for forest was reasonably high (>90%). The technique applied in this study can be extended for operational mapping and monitoring of deforestation in the tropics, particularly for those regions which are often covered by cloud.     

Cartographic Aspects of Land Cover Change Detection (Over- and Underestimation in the I&CORINE Land Cover 2000 Project)

Abstract

This paper presents the results of analysis of the data obtained by the method of computer-aided visual interpretation of satellite images used for identification of changes in land cover within the framework of the Image and CORINE Land Cover 2000 (I&CLC2000) Project (jointly managed by the European Environment Agency in Copenhagen, Denmark and the Joint Research Centre of the European Commission in Ispra, Italy). These data are also relevant in cartography. Land cover changes identified by the method mentioned may contain mistakes caused by over- or underestimation. The paper describes these mistakes. Overestimation (technical change) of the extent of land cover change is caused by adding the residual polygons (smaller than 25 ha) to neighbouring polygons. Underestimation is caused by the fact that discernible changes concerning areas larger than 5 ha which showed up in objects with areas smaller than 25 ha were not identified and, consequently, not included in either CLC90 or CLC2000 data layers; e.g. Dutch CLC_change database users' accuracy indicates an overestimation of 8.8% whereas the comparison of net change indicates a small, insignificant underestimation. In spite of the problems referred to, caused by overestimation or underestimation, the datasets on land cover changes in Europe for the 1990s and the year 2000 (± one year) can also be used for the compilation of land cover change maps at the regional, national and European levels.     

Impact of Topography on Accuracy of Land Cover Spectral Change Vector Analysis Using AWiFS in Western Himalaya

The present paper discusses the impact of topography on accuracy for land cover classification and “from-to class change using improved spectral change vector analysis suggested by Chen et al. (2003). Two AWiFS sensor images of different dates are used. Double Window Flexible Pace Search (DFPS) is used to estimate threshold of change magnitude for change/no change classes. The topographic corrections show accuracy of 90% (Kappa coefficient 0.7811) for change/no change area as compared to 82% (Kappa coefficient 0.6512) in uncorrected satellite data. Direction cosines of change vector for determining change direction in n-dimensional spectral space is used for image classification with a minimum distance categorizing technique. The results of change detection are compared (i) Improved CVA with conventional two bands CVA and (ii) Improved CVA before and after topographic corrections. The improved CVA with topographic correction consideration using slope match show maximum accuracy of 90% (Kappa coefficient 0.83) as compared to conventional CVA which show maximum accuracy of 82% (Kappa coefficient 0.6624). The overall accuracy of ”from- to class using improved CVA increases from 86% (Kappa coefficient 0.7817) to 90% (Kappa coefficient 0.83) after topographic corrections. The improved CVA with proper topographic corrections is found to be effective for change detection analysis in the rugged Western Himalayan terrain.     

Using Pattern‐oriented Modeling (POM) to Cope with Uncertainty in Multi‐scale Agent‐based Models of Land Change

Local land‐use and ‐cover changes (LUCCs) are the result of both the decisions and actions of individual land‐users, and the larger global and regional economic, political, cultural, and environmental contexts in which land‐use systems are embedded. However, the dearth of detailed empirical data and knowledge of the influences of global/regional forces on local land‐use decisions is a substantial challenge to formulating multi‐scale agent‐based models (ABMs) of land change. Pattern‐oriented modeling (POM) is a means to cope with such process and parameter uncertainty, and to design process‐based land change models despite a lack of detailed process knowledge or empirical data. POM was applied to a simplified agent‐based model of LUCC to design and test model relationships linking global market influence to agents’ land‐use decisions within an example test site. Results demonstrated that evaluating alternative model parameterizations based on their ability to simultaneously reproduce target patterns led to more realistic land‐use outcomes. This framework is promising as an agent‐based virtual laboratory to test hypotheses of how and under what conditions driving forces of land change differ from a generalized model representation depending on the particular land‐use system and location.     

都江堰震后土地利用/覆被变化信息提取方法研究

快速和精确评估"5·12"汶川地震后的土地利用/覆被变化对科学减灾、灾后重建及生态环境恢复具有重要意义。常规方法从遥感图像上提取土地利用/覆被变化信息时,多以研究区整体为处理对象,直接对全图像进行分类提取,容易忽略地形地貌和地质构造等背景因素对分类结果的影响。本文以都江堰为试验区,根据地质构造展布特征及地形地貌发育形态将其分成平原区(Ⅰ区)、低山区(Ⅱ区)、中高山区(Ⅲ区)和高山区(Ⅳ区)。对Ⅰ区采用ISODATA方法进行非监督分类;对Ⅱ区和Ⅲ区分别采用最大似然(ML)分类法进行监督分类;对Ⅳ区采用人机交互解译方法进行分类。试验结果表明,基于地理地质环境的分块分类方法是高效、精确的。     

基于IEM模拟的干旱区多时相数据含水含盐量反演模型及分析

根据干旱区的一些自然地理特征，利用IEM模型生成干旱区的多时相（少雨期、多雨期）后向散射数据，然后对数据进行统计分析。一方面印证了多雨期与少雨期后向散射差（αwet^0-αdry^0）与土壤介电常数高度相关的实验观察；另外一方面根据大量的模拟数据找到确切的（αwet^0-αdry^0）与土壤介电常数的关系。最后对盐渍化干旱区的情况（有的干旱区有严重的盐渍化）进行了探讨，发现后向散射系数差（αwet^0-αdry^0）与大介电常数虚部差成较好的线性关系，这为反演土壤含盐量提供了一定依据，但由于介电常数虚部是由含水含盐量两个量决定的，所以要直接反演出含水含盐量还需要进一步研究。     

三江源地区基于MODIS数据地表温度与土地覆盖定量关系研究

以三江源自然保护区为研究区,基于MODIS L1 B数据,采用劈窗算法反演地表温度,分析了地表温度空间分布的特征,与计算得到的归一化植被指数进行回归分析。结果表明地表温度与归一化植被指数存在很好的负相关性。分析讨论了地表温度的空间分布与土地覆盖及其他影响因子之间存在的定量关系,探讨了植被生产力与气候变化之间的相互作用以及发展趋势。研究结果有利于三江源湿地的生态保护,可为土地覆盖的动态监测提供有力的科学参考。     

The Influence of Digital Surface Model Choice on Visibility‐based Mobile Geospatial Applications

In this work we investigate the effectiveness of different types of visibility models for use within location‐based services. This article outlines the methodology and results for our experiments, which were designed to understand the accuracy and effects of model choices for mobile visibility querying. Harnessing a novel mobile media consumption and authoring application called Zapp, the levels of accuracy of various digital surface representations used by a line of sight visibility algorithm are extensively examined by statistically assessing randomly sampled viewing sites across the 1 km² study area, in relation to points of interest (POI) across the University of Nottingham campus. Testing was carried out on three different surface models derived from 0.5 m LiDAR data by visiting physical sites on each surface model with 14 random point of interest masks being viewed from between 10 and 16 different locations, totalling 190 data points. Each site was ground‐truthed by determining whether a given POI could be seen by the user and could also be identified by the mobile device. Our experiments in a semi‐urban area show that choice of surface model has important implications for mobile applications that utilize visibility in geospatial query operations.     

Integrating Remote Sensing Techniques,Geographical Information Systems (GIS), and Stochastic Models for Monitoring Land Use and Land Cover (LULC) Changes in the Northern Coastal Region of Nayarit,Mexico

Land use and land cover (LULC) changes in northern Nayarit, Mexico were estimated using post-classification change detection methods and a Markov chain model. Three thematic maps were generated by classifying Landsat images from 1973, 1900, and 2000, which were then overlaid to generate three change-detection matrices to assess the intensity and direction of changes. Between 25% and 30% of the region displayed LULC changes, attributable to a stochastic behavior that can be modeled with a first-order Markov chain. The steady-state distribution estimates indicate that the LULC patterns in the region have not yet reached equilibrium and predict the expansion of the agricultural boundaries.     

土地覆被变化对陆地碳循环的影响—以黄河三角洲河口地区为例

土地利用/土地覆被变化是全球变化研究的重点，是影响陆地碳循环的一个重要因子。该文对黄河三角洲河口地区1992年和1996年9月份的TM影像进行非监督分类，做出该地区土地覆被类型分布图，以及估算土地覆被类型的变化面积，计算结果显示1992年该研究地区植被碳库和土壤碳库分别为11.43×10     

关于图解(航测)法在浙江省土地确权中精度影响因素的探讨

开展土地确权登记是贯彻党的"十八大"精神,开展不动产登记的重要内容,是中央的重大决策部署。农业部经过多年试点颁发了土地确权标准,是基于全国统盘考虑的。浙江省人多地少,且地块面积小,大多数分布在丘陵山区地带,通过图解法能否满足土地土地确权标准要求,笔者通过对某地区的试验,得出结论与体会,以飨读者。     

基于遥感和GIS的中国土地潜力资源的研究

在对中国土地资源综合研究基础上,利用已有研究成果,借助ＧＩＳ工具,利用层次分析法,对中国土地地潜力资源进行了综合分析和评价,在评价基础上,对中国土地资源的耕地潜力、生产潜力、生产潜力总量、人口容量潜力及综合潜力的大小和空间展布特征进行分析。结论为：中国土地资源潜力很力,但时空分布不均,在开发利用中,应因地制宜,采取不同的开发、利用的战略方针,在保护好现有土地资源和合理科学利用的基础上,谨慎开发,以     

The network K‐function in context: examining the effects of network structure on the network K‐function

The flaws of using traditional planar point‐pattern analysis techniques with network constrained points have been thoroughly explored in the literature. Because of this, new network‐based measures have been introduced for their planar analogues, including the network based K‐function. These new measures involve the calculation of network distances between point events rather than traditional Euclidean distances. Some have suggested that the underlying structure of a network, such as whether it includes directional constraints or speed limits, may be considered when applying these methods. How different network structures might affect the results of the network spatial statistics is not well understood. This article examines the results of network K‐functions when taking into consideration network distances for three different types of networks: the original road network, topologically correct networks, and directionally constrained networks. For this aim, four scenarios using road networks from Tampa, Florida and New York City, New York were used to test how network constraints affected the network K‐function. Depending on which network is under consideration, the underlying network structure could impact the interpretation. In particular, directional constraints showed reduced clustering across the different scenarios. Caution should be used when selecting the road network, and constraints, for a network K‐function analysis.     

The Contribution of the Cartographic Visualisation in Understanding the Historical Geography of an Old Land Property Regime in Mouth Athos (Karyes)

Abstract

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The peninsula of Mount Athos is the largest monastic gathering of Modern Orthodoxy in the world, operating continually under the same regime since 883 AD. Focusing on Mount Athos, this paper attempts to examine the spatial regime continuation and identify the relation to what is considered to be a small residential unit around a central church (Protatos) within the limits of the Athos peninsula. The paper investigates the delimitation of the area, mapping and recording the relevant changes cartographically. At the same time, the paper creates a cadastral plan of the present regime, recording real estate owners in a cadastral table. Finally, the paper focuses on the significance of the findings to the historical geography of Athos, as well as the emergence of a new ‘area’, added to the twenty monasteries of the peninsula after 1450.     

The status of Earth Observation (EO) & Geo-Information Sciences in Africa – trends and challenges

ABSTRACT

Over the last 20 years, Africa has witnessed a slow but steady advancement in space-based technologies as they are increasingly recognized as an essential tool for decision-making that can leapfrog African development. A critical review on the outcome of a survey questionnaire focused on African private sector industries and universities, services and education/training in EO and Geo-Information Sciences, combined with literature review, and personal contacts reveal optimism for success in four sectors. These include the public sector (Government ministries and departments); Academic institutions (universities/colleges/national or regional centers); and space agencies and private sector companies. These sectors are intertwined and fundamental for creating an enabling environment for solutions to a broad spectrum of pressing priorities: job creation, poverty alleviation, and sustainable resource management. The result shows that there is an uptake in the number of institutions and market segments created. To date, there are more than 90 academic institutions and over 53 national space agencies in 28 countries. Within the 53 national space agencies, 11 African countries have already launched a total of 36 satellites into orbit, and additional five are expected by the first quarter of 2021; another five by 2025; thus, amounting to 46 satellites not foreseen ten years ago. In addition, there are now ten receiving and tracking stations in six African countries and 17 scientific National Associations or Societies with specialized expertise in Geo-Information technologies. The updated survey on the private sector in 2019 ascertained that around 4110 people are working in 130 of the 229 EO and Geo-Information Science companies identified in Africa. Ongoing investigations reiterate that companies dealing with space-based datasets and Geo-Information Sciences together with the private spin-off companies today absorb more than 15,000 people and the assumption is that this number is going to exceed 100,000 by the year 2025.     

基于新陈代谢的PGM(1,1)模型在建筑物变形监测中的应用

针对目前灰色理论模型在变形监测中的应用,本文分析了PGM(1,1)模型中的参数及其求解的方法;对于建模时前期观测值对后期预测值的影响,引入新陈代谢理论,通过整体最小二乘求解得到模型的背景值。结合高层建筑物沉降监测的实例进行计算分析,结果表明,基于新陈代谢的PGM(1,1)模型相比于传统的GM(1,1)模型,在建筑物沉降预测方面具有较好的效果。     

地理信息系统(GIS)在新发H7N9禽流感防控中的应用

通过对H7N9禽流感防控研究的归纳,总结了目前GIS技术在新发H7N9禽流感疫情的时空分布、流行规律、影响因素和风险评估等方面的应用研究,揭示了GIS技术在疫情防控中发挥的重要作用,为其他传染病特别是新发传染病的防控研究提供了借鉴。