基于机载LiDAR和倾斜影像的城市三维建模方法

"数字孪生"城市建设是近两年新兴的一条建设智慧城市的技术路径,它是构建一个与现实物理城市匹配对应的数字城市,实现城市要素数字化,其核心数据之一是高度仿真的城市三维模型.本文在研究机载LiDAR点云、倾斜摄影和三维可视化等技术之后,探讨了利用机载LiDAR和倾斜影像进行互补融合,构建城市三维模型的方法,并详细描述了三维建...     

Subsistence strategies of prehistoric hunter-gatherers on the Tibetan Plateau during the Last Deglaciation

The study of prehistoric hunter-gatherer subsistence strategies on the Tibetan Plateau is important for understanding the mechanisms and processes of human adaption to high altitude environments.But to date,only a few Paleolithic sites have been found on the Tibetan Plateau with clear stratigraphy and reliable dating.These sites are mainly distributed in the Qinghai Lake Basin on the northeastern part of the plateau,and the sporadic fauna and flora remains excavated provide limited information about the subsistence strategies of hunter-gatherers.In 2014,relatively abundant animal remains were unearthed in the Lower Cultural Layer (LCL,15400-13100 cal yr BP) of the"151 site"located in the Qinghai Lake Basin,providing important information about human subsistence strategies on the Tibetan Plateau during the Last Deglaciation.Zooarchaeological analysis of these faunal remains indicates that hunter-gatherers at the"151 site"mainly targeted large ungulates of Bos and wild horse/ass,and only brought back the most nutritious parts of animal carcasses including upper and intermediate limb bones,heads,and trunks (ribs and vertebrae).People then processed and consumed the carcasses around single hearths.Our comprehensive analyses of contemporaneous sites in the Qinghai Lake Basin show that a subsistence strategy involving opportunistic hunting of ungulates,high mobility,and short occupation of campsites was used by terminal Pleistocene huntergatherers to adapt to the high-altitude environment on the Tibetan Plateau.This subsistence strategy may have been a first step of gradual hunter-gatherer adaptation to the extreme conditions on the Tibetan Plateau after the Last Glacial Maximum,and laid the foundation for the widespread distribution of hunter-gatherers on the plateau during the Holocene.     

The Impact of Tibetan Plateau Snow Cover on the Summer Temperature in Central Asia

The current work examines the impact of the snow cover extent (SCE) of the Tibetan Plateau (TP) on the interannual variation in the summer (June?July?August) surface air temperature (SAT) over Central Asia (CA) (SAT_CA) during the 1979?2019 period. The leading mode of the summer SAT_CA features a same-sign temperature anomalies in CA and explains 62% of the total variance in SAT_CA. The atmospheric circulation associated with a warming SAT_CA is characterized by a pronounced high-pressure system dominating CA. The high-pressure system is accompanied by warm advection as well as descending motion over CA, favoring the warming of the SAT_CA. Analysis shows that the interannual variation in the summer SAT_CA is significantly positively correlated with the April SCE over the central-eastern TP. In April, higher than normal SCE over the central-eastern TP has a pronounced cooling effect on the column of the atmosphere above the TP and can persist until the following early summer. Negative and positive height anomalies appear above and to the west of the TP. In the following months, the perturbation forcing generated by the TP SCE anomalies lies near the western center of the Asian subtropical westerly jet (SWJ), which promotes atmospheric waves in the zonal direction guided by the Asian SWJ. Associated with this atmospheric wave, in the following summer, a significant high-pressure system dominates CA, which is a favorable condition for a warm summer SAT_CA.     

不同对流层天顶延迟模型在中国西北地区适应性研究

基于Fortran语言对GAMIT10.7软件进行二次开发,实现了Hopfield模型、Saastamoinen模型、Black模型、UNB3模型、EGNOS模型、GPT2w_1+ Saastamoinen模型和GPT2w_5+ Saastamoinen模型在中国西北地区的对流层延迟解算服务,并分析不同对流层延迟模型在...     

青海湖盆地史前狩猎采集人群的石料利用策略研究

史前人类向青藏高原扩散的过程和适应高海拔缺氧环境的机制是多学科关注的热点科学问题。青海湖盆地是青藏高原旧石器-中石器时代遗址分布最为丰富的区域,对这些遗址出土的石制品原料的分析有助于深入理解青藏高原史前狩猎采集人群的石料开发策略、人群迁徙和交流联系。青海湖盆地151遗址出土的928件石制品的石料研究分析显示,处于末次冰消期的下文化层的石制品以近源的石英和石英岩为主要原料,而处于全新世早中期的上文化层在同类型近源石料仍占主体地位的情况下,开始出现较高比例和多样化的优质硅质石料,并且主要用于生产细石器。野外调查和查阅地质资料均未发现青海湖盆地内有151遗址中出现的同类型优质硅质石料产出,推测其来自远距离搬运。青海湖盆地内其他8个末次冰消期至全新世中期遗址的3269件石制品石料分析结果显示,与151遗址同类型的远源优质硅质石料在全新世早期开始在盆地内的遗址中出现。这一结果表明青海湖盆地末次冰消期古人类活动强度和范围有限,全新世早中期古人类受到全新世大暖期气候变好和周边地区农业人群兴起挤压活动空间的双重影响,在高原上的活动范围和强度大大增加,伴随着开始有意识地开发优质石料,较频繁地进行远距离迁...     

Roof model recommendation for complex buildings based on combination rules and symmetry features in footprints

Currently, very few roof shape information for complex buildings is available on OSM. Moreover, additional data requirements (e.g. 3D point clouds) limit the applicability of many roof reconstruction approaches. To mitigate this issue, we propose an approach to roof shape recommendations for complex buildings by exploring the inherited characteristics of building footprints: the disclosure of rectangles combinations in a partition of footprints and the symmetrical features of footprints. First, it decomposes a complex footprint into rectangles by using an advanced minimal non-overlapping cover algorithm. Second, a graph-based symmetry detection algorithm is proposed to identify all the symmetrical sub-clusters in partitions. Then, a set of selection rules are defined to rank partitions, and the best ones are chosen for roof shape recommendation. Finally, a set of combination rules and a symmetry rule are defined. It enables to evaluate the probability of a footprint being a certain combination of roof shapes. Experimental results show the growth of the probability of correctly recommending roof shapes for single rectangles and buildings from a prior probability of 17–45% and from a prior probability of 0.29–14.3%, removing 60% and 93% of the incorrect roof shape options, respectively.     

基于遥感的青岛市区土地利用动态变化研究

基于青岛市区2005年4月和2015年4月的TM影像,利用ENVI中监督分类法,结合人工目视解译,得出2005年和2015年青岛市区土地利用类型分布情况。利用土地利用类型动态模型,分析了10年间青岛市土地利用类型的变化规律。认为2005—2015年,青岛市土地利用类型产生了较大的变化,建设用地、耕地、水面、草地、林地的面积变化显著。其中,建设用地面积增加200.98 km~2;耕地面积减少105.89 km~2;水面面积减少76.68 km~2;草地面积减少69.53 km~2;林地面积增加54.45 km~2;未利用土地面积减少。说明青岛市区处于土地利用发展的时期,政府应该注重土地资源的合理利用。     

Room semantics inference using random forest and relational graph convolutional networks: A case study of research building

Semantically rich maps are the foundation of indoor location‐based services. Many map providers such as OpenStreetMap and automatic mapping solutions focus on the representation and detection of geometric information (e.g., shape of room) and a few semantics (e.g., stairs and furniture) but neglect room usage. To mitigate the issue, this work proposes a general room tagging method for public buildings, which can benefit both existing map providers and automatic mapping solutions by inferring the missing room usage based on indoor geometric maps. Two kinds of statistical learning‐based room tagging methods are adopted: traditional machine learning (e.g., random forests) and deep learning, specifically relational graph convolutional networks (R‐GCNs), based on the geometric properties (e.g., area), topological relationships (e.g., adjacency and inclusion), and spatial distribution characteristics of rooms. In the machine learning‐based approach, a bidirectional beam search strategy is proposed to deal with the issue that the tag of a room depends on the tag of its neighbors in an undirected room sequence. In the R‐GCN‐based approach, useful properties of neighboring nodes (rooms) in the graph are automatically gathered to classify the nodes. Research buildings are taken as examples to evaluate the proposed approaches based on 130 floor plans with 3,330 rooms by using fivefold cross‐validation. The experiments conducted show that the random forest‐based approach achieves a higher tagging accuracy (0.85) than R‐GCN (0.79).     

遥感技术在干热岩选区中的应用—以鲁东地区为例

当前,全球面临能源新技术的重大变革,发展清洁低碳能源成为新潮流。而干热岩作为一种清洁能源且具有巨大的开发潜力,更是受到了社会各界人士的广泛关注。就目前来说,干热岩的研究还处于起步阶段,在靶区确定上存在很大困难。文章通过Landsat8冬季的遥感影像数据,利用Envi5.3软件对其进行754波段假彩色合成,人工解译出线环形构造;采用大气校正法,结合当地气温,排除城镇建筑物的影响,反演出地表温度和利用遥感影像来提取羟基蚀变信息。并对解译结果进行分级。然后将研究区以30个市行政区为基本评价单元,利用已收集的山东省地热资料,航磁重力异常数据,结合专家打分法与层次分析法进行权重叠加,最后运用综合评价公式对评价单元打分,得分较高的即为干热岩开发适宜区。适宜区主要是日照市,较适宜区有招远市、栖霞市、诸城市、五莲县、莒南县、青岛市、即墨区,其他市区相比较不适宜。此次研究将对改善地方投资、带动地方资源利用发挥重要作用,对有效改善鲁东地区能源供应结构、促进经济社会可持续发展具有良好的社会效益。     

LA-ICP-MS标准锆石原位微区U-Pb定年及微量元素的分析测定

LA-ICP-MS面扫描分析能直观细致地展示元素在矿物中的分布特征及相互关系,在揭示矿床成因、精细刻画成矿流体演化过程等方面具有显著优势。辽宁弓长岭铁矿床二矿区以产出沉积变质型磁铁矿富矿石而闻名,且富铁矿石的蚀变围岩中大量产出石榴石,其与富矿体成因关系密切。本文以二矿区富铁矿蚀变围岩中的石榴石为研究对象,为明确元素扩散对石榴石元素分布特征的影响,选择两颗大小不同的石榴石（1.5cm×1.5cm和0.6cm×0.7cm）,应用LA-ICP-MS在10~20Hz、20~150μm正方形激光束斑、20~150μm/s扫描速度的条件下,在4h内完成其面扫描分析,并利用无内标法对数据进行半定量校正,详细研究石榴石主量、微量和稀土元素组合及分布特征,进而有效地分析热液流体演化过程和磁铁矿富矿体的成因。LA-ICP-MS面扫描结果揭示了弓长岭厘米级石榴石连续型环带和次厘米级石榴石突变型环带的特征,准确区分了突变环带的位置和界线。分析结果表明,弓长岭二矿区厘米级石榴石中Si、Al、Fe等主量元素成分较为均一,未显示环带特征;而Mg、Mn、Ca、重稀土及Y元素均保留了原始的生长环带,具有重要的成因指示意义。该石榴石从核部到边部,其Mg含量逐渐升高,Mn含量逐渐降低,指示石榴石形成温度从核部到边部逐渐升高;而Ca含量从核部至边部先升高后降低,指示压力先升高再降低,显示进变质成因石榴石的特点。同时,该石榴石δEu值变化规律指示变质热液流体的氧逸度先减小再增大;重稀土和Y元素与Ca元素一致的变化特征表明其分布主要受压力控制。因此,结合前人研究成果综合推测,弓长岭富铁矿蚀变围岩中的石榴石形成于早元古代晚期胶—辽—吉带大陆碰撞造山过程中的进变质作用阶段,在该阶段形成的变质热液流体沿断层运移,对断层两侧的贫铁矿和围岩进行改造,从而形成富铁矿石及蚀变围岩。