对新型智慧城市三维模型“计算思维”的思考     

龚强  王丽欣 《测绘与空间地理信息》2017,40(11)

新型智慧城市地理信息公共服务平台及三维模型建设,大多应用BIM、VR、AR,以及数字航空摄影测量、高分辨率卫星遥感、无人机摄影测量系统等技术,然而,这些感官成果缺少计算思维。在大数据时代的今天,人们对地理信息成果的要求不仅能"直观看到",还要具备基于计算思维满足智能需求的计算功能。应用倾斜摄影实景三维技术构建城市地理信息底层因满足了这一需求将备受关注。  相似文献   

无人机倾斜摄影技术在环境应急中的应用     

梁炜  李雅箐 《测绘与空间地理信息》2017,40(Z1)

广西壮族自治区作为西部欠发达省份,经济亟需快速发展,因此近年来环境污染事故频发.环境污染事故的发生需要更快速的反应能力和更有效的系统模型支撑.无人机倾斜摄影技术解决了传统无人机正射航测系统的空间局限性和处理耗时长的问题,满足了环境应急对影像时间和空间上的更高要求.本文以广西壮族自治区北海市合浦县公馆镇某非法盗采的矿坑为研究区,结合固定翼无人机倾斜影像数据进行空中三角测量计算及三维建模,经模型修复后,采用SuperMap GIS 8 C系列产品进行模型单体化,并在后期评估阶段对构建的重点区域精细三维模型开展二三维GIS基础分析和应用分析,实现准确、快速、全方位、可量度地模拟污染事故现场,为环境应急的指挥决策提供更有效的空间信息技术支撑.  相似文献   

Modelling the response of a double-barred sandy beach system to time-varying wave angles     

A. Nnafie  A.S. Driessen  H.E. de Swart  T.D. Price 《地球表面变化过程与地形》2021,46(7):1393-1409

Sandy beaches typically have one or more shore-parallel bars with superimposed smaller-scale three-dimensional (3D) bars. Knowledge of their morphodynamic behaviour under more realistic wave conditions is limited. This study investigates the response of beaches with two shore-parallel bars to sinusoidally time-varying angles of incidence, using a non-linear morphodynamic model. Different periods and amplitudes of this sinusoidal variation are considered, as well as different time-mean wave angles. For time-invariant and normally incident waves, results show that alongshore rhythmic 3D bars form in the domains of inner and outer shore-parallel bars. The 3D bars in the inner domain are coupled at half the outer-bars wavelength. This phase coupling breaks up when the wave angle varies in time. Initially, regular 3D bars form in the inner domain (free behaviour), which become irregular when 3D bars develop in the outer domain (forced behaviour). The heights of the 3D bars oscillate with time, reaching maximum values when the forcing period is comparable to the system adjustment time scale (∼ 10–20 days). For a time-varying wave angle around an oblique mean, alongshore migrating 3D bars emerge in both inner and outer domains. In contrast, for an oblique (constant) wave angle, 3D bars only form in the inner domain and they hardly migrate alongshore. For any forcing period, the dominant response period of the oscillating bar heights is at half the forcing period when waves are (on average) normally incident, and it equals the forcing period when waves are on average obliquely incident. Compared with time-invariant angles, heights of inner and outer 3D bars are (on average) smaller and larger, respectively, when the angle varies with time, particularly for forcing periods in the order of the system adjustment time scale. Increasing the amplitude of the time-varying wave angle weakens bar growth. Explanations of these results are also provided.  相似文献   

From consumer to enterprise grade: How the choice of four UAS impacts point cloud quality     

Manuel Stark  Tobias Heckmann  Livia Piermattei  Fabian Dremel  Andreas Kaiser  Patrick Machowski  Florian Haas  Michael Becht 《地球表面变化过程与地形》2021,46(10):2019-2043

Uncrewed aerial systems (UAS), combined with structure-from-motion photogrammetry, has already proven to be very powerful for a wide range of geoscience applications and different types of UAS are used for scientific and commercial purposes. However, the impact of the UAS used on the accuracy of the point clouds derived is not fully understood, especially for the quantitative analysis of geomorphic changes in complex terrain. Therefore, in this study, we aim to quantify the magnitude of systematic and random error in digital elevation models derived from four commonly used UAS (XR6/Sony α6000, Inspire 2/X4s, Phantom 4 Pro+, Mavic Pro) following different flight patterns. The vertical error of each elevation model is evaluated through comparison with 156 GNSS reference points and the normal distribution and spatial correlation of errors are analysed. Differences in mean errors (−0.4 to −1.8 cm) for the XR6, Inspire 2 and Phantom 4 Pro are significant but not relevant for most geomorphological applications. The Mavic Pro shows lower accuracies with mean errors up to 4.3 cm, thus showing a higher influence of random errors. QQ plots revealed a deviation of errors from a normal distribution in almost all data. All UAS data except Mavic Pro exhibit a pure nugget semivariogram, suggesting spatially uncorrelated errors. Compared to the other UAS, the Mavic Pro data show trends (i.e. differences increase with distance across the survey—doming) and the range of semivariances is 10 times greater. The lower accuracy of Mavic Pro can be attributed to the lower GSD at the same flight altitude and most likely, the rolling shutter sensor has an effect on the accuracy of the camera calibration. Overall, our study shows that accuracies depend highly on the chosen data sampling strategy and that the survey design used here is not suitable for calibrating all types of UAS camera equally.  相似文献   

宜兴高铁新城1：1000航空摄影测量技术方案探讨     

李俊辉  姚明朝 《江苏测绘》2013,(6):50-51,54

航空摄影测量是当今大比例尺地形图制作使用最多的手段之一,航空摄影测量的生产周期短,精度指标高,成本较低,尤其适宜工期较为紧张的项目.为了确保宜兴“高铁新城”等建设的顺利开展,宜兴市规划局委托作者及其单位组织实施了区域范围内大比例尺地形测绘的项目任务.该项目采用先进的航测技术,综合利用江苏省全球导航卫星连续运行参考站综合服务系统（Jiangsu Continuously Operating Reference Stations,JSCORS）、全球定位系统（Global Positioning System,GPS）、高精度的电子水准仪、JX4等航测设备进行生产,即好又快的完成生产任务,为宜兴高铁新城的建设,提供了优良的技术保障.本文对项目实施过程中涉及到的技术方案设计、主要精度指标及其所取得的社会经济效益进行了探讨,以期为类似航测项目的开展提供借鉴.  相似文献   

利用动力伞的POS辅助航空摄影测量试验分析     

黄刚  关艳玲  任国庆  张艳亭 《测绘科学》2013,38(4)

本文以POS辅助航空摄影测量原理为基础,将新型SWDC相机、高精度激光POS和惯性稳定平台安装在轮式动力伞上进行航测试验,对试验数据进行了相关处理,处理结果满足国家航测规范要求.通过本次试验验证了将轮式动力伞应用到航空摄影测量中是可行的.  相似文献   

The specific character of limit errors in close range photogrammetry     

Feng Wenhao 《地球空间信息科学学报》2013,16(3):50-56

Close-range photogrammetry is to determine the shape and size of the object, instead of it's absolute position. Therefore, at first, any translation and rotation of the photogrammetric model of the object caused by whole geodesic, photographic and photogrammetric procedures in close-range photogrammetry could not be considered. However, it is necessary to analyze all the reasons which cause the deformations of the shape and size and to present their corresponding theories and equations. This situation, of course, is very different from the conventional topophotogrammetry. In this paper some specific characters of limit errors in close-range photogrammetry are presented in detail, including limit errors for calibration of interior elements for close-range cameras, the limit errors of relative and absolute orientations in close-range cameras, the limit errors of relative and absolute orientations in close-range photogrammetric procedures, and the limit errors of control works in close-range photogrammetry. A theoretical equation of calibration accuracy for close-range camerais given. Relating to the three examples in this paper, their theoretical accuracy requirement of interior elements of camera change in the scope of ±(0.005–0.350) mm. This discussion permits us to reduce accuracy requirement in calibration for an object with small relief, but the camera platform is located in violent vibration environment. Another theoretical equation of relative RMS of base lines (mS/S) and the equation RMS of start direction are also presented. It is proved that themS/S could be equal to the relative RMS ofmΔX/ΔX. It is also proved that the permitting RMS of start direction is much bigger than the traditionally used one. Some useful equations of limit errors in close-range photogrammetry are presented as well. Suggestions mentioned above are perhaps beneficial for increasing efficiency, for reducing production cost.  相似文献   

IMU/GPS辅助ADS80数字航空摄影测量系统的技术研究     

乔炜  吴克友  朱传勇  单静 《地理空间信息》2013,(3):106-108

详细介绍了IMU/GPS辅助ADS80数字航空摄影测量系统的基本参数和影像数据结构,对ADS80数据的空三加密精度、坐标系转换等生产中需要注意的问题进行了研究探讨,总结出ADS80数字航空摄影测量系统的多项技术特点。  相似文献   

Presentation在“摄影测量学”教学中的应用研究     

范大昭  雷蓉 《测绘与空间地理信息》2013,36(6):1-2,6

以国家精品课程"摄影测量学"建设为契机,将美英等国普遍采用的Presentation教学法应用于"摄影测量学"课堂教学中,结合多年教学实践,探讨了Presentation教学法在专业教学中的适用性以及存在的优缺点。  相似文献   

Symposium On Sediment Storage In Rivers And Estuaries     

《The Professional geographer》2013,65(4):487-488

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Physics of Desertification. Farouk El-Bazand M.H.A. Hassan, eds.

Housing the Homeless. Jon Ericksonand Charles Wilhelm, eds.

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Desert Development: Man and Technology in Sparselands. Yehuda Gradus, ed.

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The Take-off of Suburbia and the Crisis of the Central City. Günter Heinritzand Elisabeth Lichtenberger, eds.

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Spatial Transportation Modeling. Christian Werner.

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Politics and Method. Doreen Masseyand Richard Meegan, eds.

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International Migration: The Female Experience. Rita J. Simonand Caroline B. Brettell, eds.

On Geography and Its History. D.R. Stoddart.

Transportation Networks: A Quantitative Approach. D. Teodorovic.

Processes in Physical Geography. R.D. Thompson, A.M. Mannion, C.W. Mitchell, M. Parry, J.R.G. Townshend.

Imaging Radar for Resources Surveys. J.W. Trevett.

Dominance and Affection: The Making of Pets. Yi-Fu Tuan.

Capturing the Horizon. The Historical Geography of Transportation since the Transportation Revolution of the Sixteenth Century. James E. Vance, Jr.

Nations at Risk: The Impact of the Computer Revolution. Edward Yourdon.  相似文献