新型基础测绘数据生产与应用一体化实践

测绘发展经历了模拟测绘、数字化测绘和信息化测绘发展阶段,随着物联网、大数据、移动互联网等空间技术和信息技术的不断进步,测绘技术也逐渐由靠人工内、外业采集的传统测绘,发展到今天的使用卫星导航定位、无人机、物联网、大数据等先进技术手段的智能化测绘.本文从呼和浩特市智慧空间地理信息数据库的建设与应用入手,探索智慧城市建设中新型基础测绘数据生产与成果应用一体化的管理实践.     

浅析无人机影像工程化处理在测绘保障中的应用

分析了无人机的平台系统、无人机影像传输的原理,研究了影像的快速拼接、点云数据提取、TIN三角网构建、DEM数据和等高线的生成。通过对无人机影像工程化处理,为应急测绘提供实时地理空间信息保障。     

CORS站数据解算中对流层映射函数影响分析

针对不同对流层映射函数对CORS站数据解算的影响,为获知适用于我国东北部地区的对流层延迟解算策略,就CORS站数据解算中所使用的对流层映射函数进行比较分析。结论:随着卫星高度截止角的增大,NMF映射函数下NRMS值逐渐优于GMF和VMF1下的NRMS值。处理数据量大的CORS站数据,GMF映射函数具有最佳的改正效果,对我国北斗导航定位系统应用映射函数具有参考价值。     

Updating Landsat-based forest cover maps with MODIS images using multiscale spectral-spatial-temporal superresolution mapping

With the high deforestation rates of global forest covers during the past decades, there is an ever-increasing need to monitor forest covers at both fine spatial and temporal resolutions. Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat series images have been used commonly for satellite-derived forest cover mapping. However, the spatial resolution of MODIS images and the temporal resolution of Landsat images are too coarse to observe forest cover at both fine spatial and temporal resolutions. In this paper, a novel multiscale spectral-spatial-temporal superresolution mapping (MSSTSRM) approach is proposed to update Landsat-based forest maps by integrating current MODIS images with the previous forest maps generated from Landsat image. Both the 240 m MODIS bands and 480 m MODIS bands were used as inputs of the spectral energy function of the MSSTSRM model. The principle of maximal spatial dependence was used as the spatial energy function to make the updated forest map spatially smooth. The temporal energy function was based on a multiscale spatial-temporal dependence model, and considers the land cover changes between the previous and current time. The novel MSSTSRM model was able to update Landsat-based forest maps more accurately, in terms of both visual and quantitative evaluation, than traditional pixel-based classification and the latest sub-pixel based super-resolution mapping methods The results demonstrate the great efficiency and potential of MSSTSRM for updating fine temporal resolution Landsat-based forest maps using MODIS images.     

Tropical land use land cover mapping in Pará (Brazil) using discriminative Markov random fields and multi-temporal TerraSAR-X data

Remote sensing satellite data offer the unique possibility to map land use land cover transformations by providing spatially explicit information. However, detection of short-term processes and land use patterns of high spatial–temporal variability is a challenging task.We present a novel framework using multi-temporal TerraSAR-X data and machine learning techniques, namely discriminative Markov random fields with spatio-temporal priors, and import vector machines, in order to advance the mapping of land cover characterized by short-term changes. Our study region covers a current deforestation frontier in the Brazilian state Pará with land cover dominated by primary forests, different types of pasture land and secondary vegetation, and land use dominated by short-term processes such as slash-and-burn activities. The data set comprises multi-temporal TerraSAR-X imagery acquired over the course of the 2014 dry season, as well as optical data (RapidEye, Landsat) for reference. Results show that land use land cover is reliably mapped, resulting in spatially adjusted overall accuracies of up to 79% in a five class setting, yet limitations for the differentiation of different pasture types remain.The proposed method is applicable on multi-temporal data sets, and constitutes a feasible approach to map land use land cover in regions that are affected by high-frequent temporal changes.     

从测绘学向地理空间信息学演变历程

本文是对测绘学科从传统测绘到数字化测绘,再到测绘信息化即地理空间信息学3阶段发展历程的回顾。主要阐述了测绘学科伴随着国家需求和世界科技发展的进程在理念、理论、技术、方法和应用服务等方面的变化和发展,较详细地记述了如何由测绘学向地理空间信息学的演变;演变过程中测绘学的理念、学科分类和内涵有哪些变化;并且对数字化测绘、测绘信息化(地理空间信息学)等给出了基本概念和定义。     

一种基于梯度和与一致性组合策略的无缝纹理映射方法研究

针对三维纹理映射中存在接缝、颜色差异大等问题,采用基于梯度值之和的选片算法,结合一致性检查、全局颜色校正和局部颜色校正等策略,消除影像的模糊、重影与色差,实现无缝纹理映射,同时避免影像失焦和障碍物的影响,试验结果表明,该方法纹理映射效果较好。     

基于天绘卫星影像的困难地区地形图测制方法

介绍了基于天绘影像的困难地区地形图测制技术,针对困难地区地形图的特点,分析影响地形图测制的因素,总结了提高困难地区地形图成果质量的方法。     

The Boussinesq-BO equation for algebraic gravity solitary waves in baroclinic atmosphere and the research of squall lines formation mechanism

The gravity solitary waves are a kind of waves which are caused by the disturbance of static equilibrium. The nonlinearity concentration of the gravity solitary waves makes the energy assemble together and forms disastrous weather phenomena, such as squall lines. By the calculation condition and theoretical method limit, previous studies tried hard to reduce the variable numbers and discussed the gravity solitary waves in barotropic atmosphere, but the baroclinic problem of atmosphere is inevitable topic. In this paper, from the basic kinetic equations in baroclinic non-static equilibrium atmosphere, by using multi-scale analysis and perturbation method, a new model is derived to describe the algebraic gravity solitary waves, we call it Boussinesq-BO equation. Comparing with the former models, the Boussinesq-BO model can describe the propagation process of waves in two directions and is more suitable for the real atmosphere condition. With the help of the trial function method, an exact solution of Boussinesq-BO equation is obtained and the fission property of algebraic gravity solitary waves is discussed. Finally, we can find that the fission of algebraic gravity solitary waves is also a possible formation mechanism of squall lines.     

Analysis of urban built-up areas and surface urban heat island using downscaled MODIS derived land surface temperature data

Regional scale urban built-up areas and surface urban heat islands (SUHI) are important for urban planning and policy formation. Owing to coarse spatial resolution (1000 m), it is difficult to use Moderate Resolution Imaging Spectroradiometer (MODIS) Land surface temperature (LST) products for mapping urban areas and visualization, and SUHI-related studies. To overcome this problem, the present study downscaled MODIS (1000 m resolution)-derived LST to 250 m resolution to map and visualize the urban areas and identify the basic components of SUHI over 12 districts of Punjab, India. The results are compared through visual interpretation and statistical procedure based on similarity analysis. The increased entropy value in the downscaled LST signifies higher information content. The temperature variation within the built-up and its environs is due to difference in land use and is depicted better in the downscaled LST. The SUHI intensity analysis of four cities (Ludhiana, Patiala, Moga and Vatinda) indicates that mean temperature in urban built-up core is higher (38.87 °C) as compared to suburban (35.85 °C) and rural (32.41 °C) areas. The downscaling techniques demonstrated in this paper enhance the usage of open-source wide swath MODIS LST for continuous monitoring of SUHI and urban area mapping, visualisation and analysis at regional scale. Such initiatives are useful for the scientific community and the decision-makers.