利用精密单点定位（PPP）方法在黑龙江省进行1∶10000像片控制测量的精度分析

通过对黑龙江省某测区利用GPS静态网和精密单点定位（PPP）两种方法对1∶10 000像片控制测量成果进行对比分析,在利用CQG2000对大地高进行高程异常改算精度同传统GPS网拟合高程进行对比分析。通过对比分析得出结论：精密单点定位（PPP）方法施测的像控点平面精度能够满足1∶10 000地形图更新、山区1∶10 000地形图测绘中±1 m的精度要求。同时也验证了＂我国大陆重力大地水准面CQG2000绝对精度在东经120°以东高于±0.3 m的可靠性。     

新冠疫情下城市应急医疗设施空间配置评价研究——以武汉市为例

通过数据实证分析COVID-19期间武汉市应急医疗设施的空间配置特征,构建武汉市疫情暴发期间的应急医疗设施空间配置评价体系,运用两步移动搜寻法等方法对武汉市应急医疗资源配置进行评价,提出其空间配置中的不足。研究发现,COVID-19暴发期间武汉的应急医疗设施的空间分布以核心城区为主,开放床位多集中在传统城市中心地区,周边地区的应急医疗设施空间配置上仍有不足;应急医疗设施的配置存在较大的缺口,空间分布不均衡,且综合可达性较差,可服务的研究单元较为局限,应急设施的就医可达性由城市中心从内向外依次降低。     

Getting Away with the Stolen Vehicle: An Investigation of Journey-after-Crime*

Abstract

Analyses of criminals' travel patterns can provide significant suggestions to improve crime management. This study extends the investigation of criminals' travel behavior from journey-to-crime to journey-after-crime. Moreover, new methods are developed to examine the spatial patterns of location pairs when restricted by the underlying geographical process. The methods are employed to investigate criminals' journey-after-auto-theft in the city of Buffalo, New York. The analyses reveal that auto thieves' trips from vehicle-theft locations to the corresponding vehicle-recovery locations are local in nature. The travel distances are significantly shorter than the randomly simulated trips; the travel directions are biased from the random directions as well.     

COUNCIL MEETING,ATLANTA April 13-14, 1973

In this second report from the Long Range Planning Committee, the Chairman of the Communications Task Force discusses the purpose, structure, and functioning of Specialty Groups, which are to be established in accordance with a Committee recommendation approved by the AAG Council.     

Tectonics,geomorphology and water mill location in Scotland,and the potential impacts of mill dam failure

In this paper we assess the ways in which the topography of glaciated northern Britain has affected the siting and operations of water mills, and compare those factors and mill locations for mills in unglaciated southern Britain. We then explore the impacts of these findings on the potential downstream impacts of mill dam failure.We used a GIS to plot the locations of all 1712 localities in Britain's Ordnance Survey Gazetteer that include “mill”, “milton” (‘milltown’) and “miln” in their name. We then examined the geomorphology of mill locations in two study areas, one in northeast Scotland (glaciated; 421 localities) and one in southern England (unglaciated; 438 localities), assessing (i) mill location within the drainage net, and (ii) the steepness of an adjacent stream within a radius of 500 m of the mill locality. The large majority of mills are located within the first 10 km of the drainage net in both study areas, presumably on relatively stable bedrock channels. The data for most of the mills in both study areas indicate that catchment areas of less than 200 km² are sufficient to supply the water necessary for operation of a mill, but the higher rainfalls and runoff in Scotland (almost twice the values in the England study area) mean that mill dams in S England must have been higher and of higher capacity than those in NE Scotland. That finding is consistent with the results related to channel steepness, which show that mills in Scotland are associated with steeper channels than is the case in England. The generally greater channel steepness in Scotland (and the greater downstream extent of those steeper channels, as also confirmed by the data) reflect both the many glacially steepened bedrock channel reaches in Scotland and the steepening of Scotland's coastal bedrock channels as a result of glacio-isostatic rebound.The technical requirements of water mill operation favour situations where water can be delivered to the top of, or at least part-way up, the mill wheel. Scotland's steeper rivers and its higher rainfalls mean that Scotland's mills require smaller mill dams, if they are needed at all. It would therefore be expected that catastrophic or managed failure of mill dam walls in northern Britain would release lower volumes of trapped sediment to the downstream fluvial system. These lower volumes would in turn result in lower geomorphological impacts downstream of the dam, both in terms of changing channel patterns and burial of the bed. Such dam failure is a key current issue in geomorphology and one case study of a small failed mill dam in western Scotland confirms the minimal downstream impacts of that failure.     

Megaurbanization and Industrial Relocation in Mexico's Central Region

Recent changes involving Mexico City, the main metropolis in Mexico and one of the world's largest megacities, are a slowing demographic growth and the relocation of industrial activities from the city proper to other cities in the Central Region. One of the important features of this process is the extension of existing location economies for manufacturing industries from the strictly urban, or metropolitan scale, to a somewhat more regional level. This paper argues that this territorial restructuring is highly influenced by four main processes: (1) a spatially selective industrialization where a few cities, rural areas and economic corridors are emerging as industrial locations; (2) accessibility and transaction flows where the main road network and commodity flows determine the primary urban structure and the formation of economic corridors; (3) a concentrated pattern of foreign investment that shows a marked preference for the urban "core" and which reinforces its economic importance; (4) a territorial industrial specialization pattern whose main feature is a mixture of dispersion and concentration trends according to the type of manufacturing industry. Territorial restructuring in this region is an excellent example of an emerging spatial order associated to megaurbanization, with a rapid growth of nearby cities, a polycentric urban pattern, and the arrival of manufacturing industry in selective sites. However, this process seems to reinforce current intraregional inequalities, as the places with the best economic advantages tend to receive larger investments.     

水力压裂对速度场及微地震定位的影响

水力压裂是页岩气开发过程中的核心增产技术,微地震则广泛用于压裂分析、水驱前缘监测和储层描述.微地震反演过程中,用于反演的速度模型往往基于测井、地震或标定炮资料构建,忽略了压裂过程中裂缝及孔隙流体压力变化对地层速度的影响.本文首先基于物质守恒、渗流理论和断裂力学模拟三维水力压裂过程,得到地下裂缝发育特征和孔隙压力分布.继而根据Coates-Schoenberg方法和裂缝柔量参数计算裂缝和孔隙压力对速度场的影响,得到压裂过程中的实时速度模型.最后利用三维射线追踪方法正演微地震走时和方位信息,并采用常规微地震定位方法反演震源位置及进行误差分析.数值模拟结果表明,检波器空间分布影响定位精度,常规方法的定位误差随射线路径在压裂带中传播距离增加而变大,且不同压裂阶段的多点反演法与单点极化法精度相当.     

瀑布沟水库区域小震重新定位与地震性质研究

利用双差定位法对瀑布沟水库及邻区1 834次小震进行了重新定位,并对距水库水域最近的2个小震集中区的地震性质进行了分析。重新定位后得到1 708次小震结果,定位残差由原来的0.93s降为0.21s,水平向估算误差平均为0.6km,垂直向估算误差平均为2.9km; 平面空间分布显示,重新定位地震主要分布在研究区的西南(A区)、库中区(C区)和水库大坝附近(D区); A区小震密集与其处于鲜水河断裂中南段、安宁河北段和大凉山断裂北段交会区的特殊地理位置有关。C,D区高度集中分布的小震与水库蓄水无关,属于各种建设施工造成的爆破地震。     

中美两国全球6级以上地震目录对比分析

中国地震台网中心(CENC)和美国国家地震信息中心(NEIC)提供的全球地震目录经常出现较大偏差.CENC发震时刻较早,CENC震源深度较深.2001年至2010年全球6.0级以上地震约11.67％存在明显目录偏差,印度洋板块北侧集中约70％有各类偏差地震.印度洋板块北侧各项误差统计占全世界同类地震约70％,表现出较好的一致性.这种现象应与震源过程有关,与该地区S波走时异常问题耦合,而不是算法或随机误差造成的.