基于光谱角匹配算法的水体信息提取研究

针对水体信息提取时,传统算法不能较好地解决山体阴影被误提为水体的问题,引入多用于高光谱数据处理的光谱角匹配算法,以Land-sat8 OLI(band1-band7)为数据源,以黄河小浪底水库周边区域为实验区,开展水体信息提取研究,结果显示:水体指数法和波段关系提取的结果中有大量的山体阴影信息,提取精度不超过30%,而光谱角匹配法提取结果受阴影的影响较小,提取精度在99%以上。     

基于GDAL的遥感影像快速裁切技术

介绍了基于开源GDAL类库开发,实现遥感影像的大批量快速裁切的技术,经应用测试,该技术提高了遥感影像处理的作业效率和自动化水平,降低了生产成本。     

地理国情普查时点核准作业方法探讨

通过核实从数据采集到标准时点阶段发生变化的内容,补充新增内容,消除普查前阶段由于资料时效性和外业局限性等导致的现势性不统一现象,对变化的地理国情信息进行核准,使地理国情普查数据成果在时间上达到统一,是开展地理国情监测的基础。     

地理国情普查项目地表覆盖数据成果的质量控制

地理国情普查项目是全新的测绘地理信息项目,文章结合生产阶段及检查验收过程中地表覆盖数据生产容易出现的质量问题,通过认真分析影响质量的因素,从管理要素、生产过程、两级检查3个方面谈了解决该问题的部分质量控制措施,以便于更好地提高地理国情普查项目成果的质量。     

土地变更影像在棚户区改造资金监管中的应用探索

加快棚户区改造是落实国务院部署的一项政治任务,也是当前及今后一段时期内的最大民生工程。通过利用年度土地变更调查遥感影像对荣成市2015年度棚户区改造新开工项目进行甄别排查,经实地核查后获取不合格项目的具体范围和面积。研究结果表明,利用年度土地变更调查遥感影像可以有效地提高棚户区改造资金监管中对于项目定性效率,并推进资源共享共建,为政府决策提供科学依据。     

基于遥感数据的哈尔滨土地利用/覆被变化研究

以哈尔滨市为例,基于Landsat数据,利用遥感技术和GIS技术对2000和2015年的遥感影像数据进行解译分类,通过对分类结果的统计分析,定量研究哈尔滨市15年间的土地利用变化过程,结果显示:哈尔滨市土地综合利用程度较高,区域内耕地面积减少;相反,城市建成区面积大幅增加,区域内绿地面积逐年减少,应注意生态环境维护保持。     

2000～2015年会理县地表覆盖变化监测

以LandSat多时相影像为数据源,采用基于规则的面向对象分类方法,监测会理县2000～ 2015年地表覆盖变化.结合1∶50 000 DEM数据,分析了会理县地表覆盖构成与转移、变化动态度及潜在退耕地情况.监测分析结论能为会理县加强空间管制、促进土地资源集约利用、指导生态文明建设等提供决策信息支撑.     

Selection and quality assessment of Landsat data for the North American forest dynamics forest history maps of the US

Using the NASA Earth Exchange platform, the North American Forest Dynamics (NAFD) project mapped forest history wall-to-wall, annually for the contiguous US (1986–2010) using the Vegetation Change Tracker algorithm. As with any effort to identify real changes in remotely sensed time-series, data gaps, shifts in seasonality, misregistration, inconsistent radiometry and cloud contamination can be sources of error. We discuss the NAFD image selection and processing stream (NISPS) that was designed to minimize these sources of error. The NISPS image quality assessments highlighted issues with the Landsat archive and metadata including inadequate georegistration, unreliability of the pre-2009 L5 cloud cover assessments algorithm, missing growing-season imagery and paucity of clear views. Assessment maps of Landsat 5–7 image quantities and qualities are presented that offer novel perspectives on the growing-season archive considered for this study. Over 150,000+ Landsat images were considered for the NAFD project. Optimally, one high quality cloud-free image in each year or a total of 12,152 images would be used. However, to accommodate data gaps and cloud/shadow contamination 23,338 images were needed. In 220 specific path-row image years no acceptable images were found resulting in data gaps in the annual national map products.     

Historical paths to current unrest: Extending the temporal lens in analysing geographies of agrarian change and conflict

The proliferation of soybean monoculture and its expansion into previously marginal territories in Argentina have resulted in land conflicts and attacks on peasant communities that possess land without having secured tenure. However, the rapid and intensive modernisation and industrialisation of agriculture production has had differentiated effect on different territories in Argentina. This article posit that understanding these differences requires an extended temporal analysis. While social research tends to focus on the present or recent past, this paper joins calls for greater attention to historical context and processes when examining current social dynamics and geographies. Focusing on the province of Santiago del Estero in Northwest Argentina, this paper provides a particular temporal-thematic approach for conducting such a historical path analysis, which here focuses on the province’s changing agrarian structures and political shifts that resulted in a complex, irregular and subsequently unstable land tenure system.     

Flow processes and sedimentation in unidirectionally migrating deep‐water channels: From a three‐dimensional seismic perspective

Three‐dimensional seismic data were used to infer how bottom currents control unidirectional channel migration. Bottom currents flowing towards the steep bank would deflect the upper part of sediment gravity flows at an orientation of 1° to 11° to the steep bank, yielding a helical flow circulation consisting of a faster near‐surface flow towards the steep bank and a slower basal return flow towards the gentle bank. This helical flow model is evidenced by the occurrence of bigger, muddier (suggested by low‐amplitude seismic reflections) lateral accretion deposits and gentle channel wall with downlap terminations on the gentle bank and by smaller, sandier (indicated by high‐amplitude seismic reflectors) channel fills and steep channel walls with truncation terminations on the steep bank. This helical flow circulation promotes asymmetrical depositional patterns with dipping accretion sets restricted to the gentle bank, which restricts the development of sinuosity and yields unidirectional channel migration. These results aid in obtaining a complete picture of flow processes and sedimentation in submarine channels.