Sentinel+Landsat融合影像的城市不透水面积参数获取     

肖斌  周忠赣  范军林  徐看  刘向铜 《测绘通报》2022,(4):66-71,95

不透水面是衡量城市化的发展程度和评价城市生态环境质量的重要指标之一。南昌市作为环鄱阳湖生态经济圈的典型代表区域城市之一,准确、及时、高效地获取其不透水面信息对经济发展和生态规划提供全新的决策参考具有重大意义。现有的不透水面研究大多集中在针对单一光学遥感影像数据提取不透水面信息,但受影像数据源的影响,其分类结果往往存在光谱混淆和“椒盐”现象,限制了不透水面分类精度的进一步提高。为了改善这一局面,本文以南昌市为研究区,综合考虑多源遥感影像数据各自具有的影像特征优势,探究基于Sentinel+Landsat影像提取不透水面信息的适用性与优劣性。  相似文献   

三维建筑模型单体化的深度学习技术实现     

王文娜  张弓  吴侃  王瑞  亓立壮 《测绘通报》2022,(12):14

倾斜摄影三维建模技术能够快速建立目标区域的实景三维模型,但是该机制下的模型为连续不规则三角网（TIN）,无法对其中具体的地理对象进行分析。本文采用深度学习语义分割方法提取建筑物,并与传统面向对象的影像分析提取结果进行对比。研究表明语义分割方法能够有效提取倾斜模型对应数字正射影像中的建筑物。通过对提取结果进行后处理得到建筑物矢量面,为每个建筑物添加基本属性信息,利用矢量面实现建筑物单体化并发布三维模型和数据服务,能够更有效地利用倾斜摄影模型展示研究区域地理空间和建筑物信息。  相似文献   

Homogeneous reprocessing of GPS,GLONASS and SLR observations   总被引：3，自引：2，他引：1  

Mathias Fritsche  Krzysztof Sośnica  Carlos Javier Rodríguez-Solano  Peter Steigenberger  Kan Wang  Reinhard Dietrich  Rolf Dach  Urs Hugentobler  Markus Rothacher 《Journal of Geodesy》2014,88(7):625-642

The International GNSS Service (IGS) provides operational products for the GPS and GLONASS constellation. Homogeneously processed time series of parameters from the IGS are only available for GPS. Reprocessed GLONASS series are provided only by individual Analysis Centers (i. e. CODE and ESA), making it difficult to fully include the GLONASS system into a rigorous GNSS analysis. In view of the increasing number of active GLONASS satellites and a steadily growing number of GPS+GLONASS-tracking stations available over the past few years, Technische Universität Dresden, Technische Universität München, Universität Bern and Eidgenössische Technische Hochschule Zürich performed a combined reprocessing of GPS and GLONASS observations. Also, SLR observations to GPS and GLONASS are included in this reprocessing effort. Here, we show only SLR results from a GNSS orbit validation. In total, 18 years of data (1994–2011) have been processed from altogether 340 GNSS and 70 SLR stations. The use of GLONASS observations in addition to GPS has no impact on the estimated linear terrestrial reference frame parameters. However, daily station positions show an RMS reduction of 0.3 mm on average for the height component when additional GLONASS observations can be used for the time series determination. Analyzing satellite orbit overlaps, the rigorous combination of GPS and GLONASS neither improves nor degrades the GPS orbit precision. For GLONASS, however, the quality of the microwave-derived GLONASS orbits improves due to the combination. These findings are confirmed using independent SLR observations for a GNSS orbit validation. In comparison to previous studies, mean SLR biases for satellites GPS-35 and GPS-36 could be reduced in magnitude from \(-35\) and \(-38\)  mm to \(-12\) and \(-13\)  mm, respectively. Our results show that remaining SLR biases depend on the satellite type and the use of coated or uncoated retro-reflectors. For Earth rotation parameters, the increasing number of GLONASS satellites and tracking stations over the past few years leads to differences between GPS-only and GPS+GLONASS combined solutions which are most pronounced in the pole rate estimates with maximum 0.2 mas/day in magnitude. At the same time, the difference between GLONASS-only and combined solutions decreases. Derived GNSS orbits are used to estimate combined GPS+GLONASS satellite clocks, with first results presented in this paper. Phase observation residuals from a precise point positioning are at the level of 2 mm and particularly reveal poorly modeled yaw maneuver periods.  相似文献   

温度影响对虾白斑综合症病毒增殖机制的研究   总被引：1，自引：0，他引：1  

李侃  罗淑娅  徐丽美 《台湾海峡》2013,32(1):61-66

已有文献报道温度是影响虾类感染对虾白斑综合症病毒(WSSV)的重要因素但并不清楚其机制.在本实验中我们通过定量检测病毒拷贝数后发现环境温度与病毒增殖速度有相关性.当温度在21～30℃之间时病毒增殖速度最快,病虾于感染后6～8d全部死亡而高温(33℃)及较低温度(15 ～ 18℃)对病毒的增殖均具有一定的抑制作用,虾存活时间超过了14 d;当温度降至12℃或8℃时病毒增殖受到明显抑制,虾存活时间长达40 d.通过激光共聚焦显微镜观察进一步发现病毒进入宿主细胞的能力与温度密切相关,高温(33℃)和低温(12℃)下病毒进入细胞的数量明显比27℃时少;而通过对病毒iel和up28基因的转录分析发现与27℃相比,高温(33℃)和低温(12℃)明显改变了病毒基因的转录.本实验结果表明温度影响WSSV基因组的复制、转录及病毒入侵细胞的能力从而导致了病虾死亡时间上的差异.  相似文献   

滇东北铅锌成矿带会泽金牛厂筇竹寺组含矿层的发现及意义     

熊亮  朱杰勇  朱林生  贺瑾瑞  李侃  洪建磊  常苏娟  罗思亮 《矿产与地质》2010,24(6):507-512

滇东北地区是我国铅、锌、银等有色金属矿产的重要产地之一,已发现铅锌矿床、矿点和矿化点多处。以前发现的赋矿层都是碳酸盐岩,而会泽金牛厂筇竹寺组含矿层是泥质粉砂岩,此含矿层是目前滇东北铅锌成矿带中新发现的铅锌矿含矿层位,它突破了滇东北成矿带中仅碳酸盐岩中含矿的历史,显示了滇东北筇竹寺组铅锌找矿的巨大潜力。文章对该含矿层的控矿特点及矿体规模、形态进行了详细研究,以期对滇东北筇竹寺组的找矿带来新的突破。  相似文献   

地浸砂岩型铀矿镭—氡放射性平衡对伽玛测井解释结果的影响研究     

李进学  李锦  阚小波  何进军 《陕西地质》2010,28(2):66-71

地浸砂岩型铀矿钻探勘查过程中,由于钻孔内＂压氡现象＂的存在,使钻孔内铀矿层的镭—氡含量出现暂时的不平衡现象,往往会造成伽玛测井解释结果系统偏低,影响了铀矿资源量评价的准确程度。因此在地浸砂岩型铀矿勘查过程中,必须设计一定数量的物探参数孔,及时开展镭—氡放射性平衡系数的研究和评价。  相似文献   

Loss of 40Ar(rad) from leucite-bearing basanite at low temperature: implications on K/Ar dating.     

Kadosa Balogh  Károly Németh  Tetsumaru Itaya  Ferenc Molnár  Robert Stewart  Ngo X. Thanh  Hironobu Hyodo  Lajos Daróczi 《Central European Journal of Geosciences》2010,2(3):385-398

The Bakony-Balaton Highland Volcanic Field (BBHVF) is located in the central part of Transdanubia, Pannonian Basin, with over 50 alkali basaltic volcanoes. The basanite plug of Hegyestu erupted in the first phase of volcanic activity. K/Ar and Ar/Ar ages were published for the BBHVF. K/Ar and Ar/Ar ages of the leucite-bearing basanite of Hegyestás were conflicting. This is caused by the special Ar retention feature of leucite in this basanite. K/Ar ages measured in the usual way were 25–45% younger, but after HCl treatment of the rock, or after reducing the baking temperature of the argon extraction line from 250°C to 150°C, they became similar to the Ar/Ar ages. All Ar/Ar determinations were performed after HF treatment. HCl treatment dissolved olivine, nepheline, leucite, magnetite and from 1-1 sample analcime or calcite. K dissolution studies from different locations of Hegyestü have shown that K content is mostly ≈2%, but it may decrease to ≈0.3%. HCl treatment dissolved 28.0–63.5% of the K content. The calculated K concentration for the dissolved part of samples with ~2%K was 4.02-6.42%: showing that leucite is responsible for the low temperature loss of ⁴⁰Ar(rad). Ar may release at low temperature from very finegrained mineral, or when the Ar release mechanism changes. A ⁴⁰Ar(rad) degassing spectrum has been recorded in the 55–295°C range of baking temperature and the data were plotted in the Arrhenius diagram. The diagram shows that a change of the structure in the 145–295°C range caused the loss of ⁴⁰Ar(rad). On fractions of HCl treated rock 7.56±0.17 Ma isochron K/Ar age has been determined. This is regarded as minimum age of eruption and it is similar to the Ar/Ar isochron age (7.78±0.07 Ma).  相似文献   

The Loess/Paleosol record and the nature of the younger Dryas climate in central China     

David B. Madsen  Li Jingzen  Robert G. Elston  Xu Cheng  Robert L. Bettinger  Geng Kan  P. Jeff Brantingham  Zhong Kan 《Geoarchaeology》1998,13(8):847-869

The use of latest Pleistocene-Holocene paleosols in defining Chinese climatic sequences is plagued by poor chronological controls caused primarily by the use of radiocarbon dates derived from bulk soil carbon. Dating of a post-glacial aeolian/paleosol sequence in the Pigeon Mountain basin of north-central China, using culturally deposited charcoal, support a wide array of other data suggesting the Younger Dryas was a period of cooler dryer conditions marked by wide-spread aeolian deposition. Periods of soil formation and higher lake levels bracket this climatic event. Climatic variability immediately before, during and immediately after the Younger Dryas interval is associated with rapid technological elaboration and innovation in the production and use of chipped stone tools, and perhaps, ground stone. © 1998 John Wiley & Sons, Inc.  相似文献   

基于GIS的空间数据和空间数据库浅谈   总被引：4，自引：0，他引：4  

肖寒  吴侃  孙君 《江苏地质》2005,29(2):105-107

在数字城市、数字省区等数字工程建设和各个部门信息化建设迅速开展的时候，大量甚至海量空间数据的存储和管理成为地理信息系统建设工作者们面临的重要问题，研究空间数据和空间数据库变得非常迫切。简要介绍了空间数据的概念、特征和空间数据结构模型，并对空间数据库的设计做了简单阐述。  相似文献