3D地图打印技术研究

2015年9月美国3D打印机在河北省制图院落户。笔者结合其配套打印软件,组织技术人员反复实践,研发出一套符合我国实际的3D地图生产工艺流程,成功解决了基础地理信息国标数据格式向3D格式数据转换、3D地形模型编辑、3D符号设计等一系列难题。该技术融合了3ds Max、ArcGIS、Global Mapper等多种软件制图技术,具备实用性强、可操作性强、推广价值较高等优点。产品涵盖晕渲地图、正射影像地图、专题地图、物理沙盘等品种。3D打印地图具备以下特点：色彩鲜艳、地形直观逼真;色彩设计自由,富于变化;精度高;可接收多源数据;生产效率高。     

国内实景影像地图中涉密敏感内容的判定及处理方法

近年来,实景影像地图逐渐走入百姓生活,为广大用户提供了更为直观的互联网地图位置服务,优势明显。但正是由于其展示街拍实景的特点,如果处理不当,则极易造成危害国家安全的泄密事件。因此,对实景影像地图中存在的涉密风险,以及对可能出现的涉密敏感内容保持清醒的认识显得十分重要。本文结合国家法律法规对上述问题进行了分析、归纳,并针对各类涉密敏感内容的特点分别提出了行之有效的处理方法。     

论证南海海疆国界线

According to a series of important historical maps,i.e.,the Location Map of the South China Sea Islands,the Nansha Islands,Zhongsha Islands,Xisha Islands,Yongxing Island and Shidao Island,and Taiping Island(archived by the Territorial Administration Division of the Ministry of Interior of Republic of China in 1946),and the Administration District Map of the Republic of China published in 1948,the dashed line surrounding the South China Sea Islands represents China's sea boundary in the South China Sea at that time.It was both connected with,and an extension of,the land boundary of China.At that time the dashed line was used to represent the waters boundaries while the solid line was used to represent the land boundary—a universal method used in maps that was then recognized internationally.The above observation provides historical and scientific evidence of China's sea boundary in the South China Sea that is useful for the international maritime delimitation over the South China Sea area.     

Using Vertical Aerial Photography to Estimate Mass Balance at a Point

The mass balance distribution over a 0.5 km² area of the lower part of South Cascade Glacier is obtained from remotely sensed measurements of its geometry and velocity field over two periods, 1992–93 and 1993–94. Vertical aerial photography from late summer 1992, 1993, and 1994 is analyzed photogrammetrically to get surface topography of South Cascade Glacier on a 100-meter square grid. The known bed topography is subtracted from the surface topography to get the ice thickness, and the surface topographies are subtracted from each other to get the thickness change. Annual displacement vectors, determined at points where natural features could be tracked from one year to the next, are contoured by hand and interpolated to the grid. Assuming that the ice follows Glen's flow law with exponent n = 3, and that 10% of the ice flow is due to sliding at the bed, the surface velocity is scaled by 0.82 to get the average velocity in the vertical ice column. The average velocities are combined with the thicknesses to calculate the flux divergence at each of 46 gridpoints on a 100-m square grid, where it is subtracted from the thickness change to get the mass balance.
Use of the same control points from year to year makes any systematic error in photogrammetric coordinates temporally constant, so such error has no effect on the mass balance estimate. Random error in coordinates is assumed to be uncorrelated from coordinate to coordinate, from point to point, from year to year; the standard error is estimated to be 1 m, resulting in a standard error in coordinate differences of about 1.5 m. A 1 m error in a vertical coordinate has nearly twice the effect on the estimated balance that one in a horizontal coordinate has and more than ten times the effect that one in ice thickness has. Compared with measurements at a stake, the estimated balances are about 1 m too negative.     

Mass Balance of the Greenland Ice Sheet: Can Modern Observation Methods Reduce the Uncertainty?

The future contribution to sea level change from the large ice sheets in Greenland and Antarctica is composed of two terms: (i) a background trend determined by the past climate and dynamic history of the ice sheets on a range of time scales (decadal, millennial or even longer); and (ii) a rise/fall related to future climate change, whether due to anthropogenic effects or natural climate variability. The accelerating development of remote sensing techniques for monitoring ice sheet behaviour, and the use of high-resolution general circulation models to estimate temperature and precipitation changes are likely to result in improved estimates of the sensitivity of ice sheet mass balance to climate change and thereby to narrow down the uncertainty of contribution (ii). Contribution (i) is much more difficult to assess, because the mass balance displays large temporal variability on year-to-year and even on decadal time scales that masks the long-term trend. So, although modern remote sensing techniques enable accurate measurement of ice sheet surface elevation change, the mass changes derived from such measurements, even if performed over a period of several years, might just reflect a statistical fluctuation around the long-term background trend, which we must know in order to assess the future ice sheet contribution to sea level change on century and longer time scales. The measured volume changes must therefore be evaluated on the background of short- and long-term accumulation rates (e.g. determined from ice cores and high-resolution ice radar) and dynamic model studies of ice sheet evolution on century, millennial and longer time scales. The problems are illustrated by using the Greenland ice sheet as an example.     

Mass Balance of Vernagtferner, Austria, From 1964/65 to 1996/97: Results for Three Sections and the Entire Glacier

In the centre of the highly glacierized Oetztal valley, mass balance is determined for the three neighbouring glaciers Hintereisferner, Kesselwandferner and Vernagtferner, applying the direct glaciological method, related to the 'fixed date' system. The diverging behaviour of the three glaciers due to slightly varying local climatic conditions as well as to different topoclimatological and physiographic features gave reason to analyse the Vernagtferner mass balance separately for three easily discernible sections, i.e. Schwarzwand, Taschachjoch and Brochkogel, each showing characteristic aspect and elevational distributions of area respectively.
The cumulative mass balance of the Vernagtferner for the period 1968/69, when separate mass balance computations for the three sections were started, until 1996/97 amounted to −8.7 m water equivalent (w.e.). The mass loss of the western Schwarzwand section as the part with the largest share of low elevation area was −13.3 m w.e., in contrast to the central Taschachjoch section which lost only −6.6 m w.e. The remaining eastern Brochkogel section with a loss of −8.5 m w.e. fits best the mass balance of the total Vernagtferner although its physiographic characteristics differ markedly from those of the entire glacier. The equilibrium line altitude (ELA) dependence on specific net mass balance ( b ) is slightly different for the three sections, whereas the dependence of the accumulation area–total area ratio (AAR) on b is characterized by nearly identical sensitivities. Moreover, AAR correlates better with b than ELA, therefore AAR is regarded as a more representative parameter for the Vernagtferner than ELA.     

Annual Mass-balance Series of a Temperate Glacier in the Caucasus, Reconstructed from an Ice Core

Identification of annual layers in a firn/ice core provides a possibility to reconstruct the mass-balance sequence for glaciers where no direct observations have been carried out. A number of cores is obtained from the boreholes drilled on the Djantugan firn plateau in the crest zone (3620 m a.s.l.) of the Main Caucasus Ridge. A geophysical radar survey shows ice thickness here being equal to 212 m, close to the maximum value within the plateau (235 m). The deepest layer achieved, c .93 m below the surface, is dated back to 1937. Annual layers are identified by visual and textural petrographic analysis in situ . Geochemical and isotope methods are also applied. Ambiguities in discerning annual boundaries due to epigenetic firn/ice homogenization can be eliminated by means of complex methods. Since the probability of complete melting of an annual layer is estimated as negligible, the reconstructed continuous mass-balance time series, after inserting rheological and inclinometrical amendments, describe the character of glacier evolution. It is corroborated with indirect calculation using data from the nearest weather station and with mass-balance series of the neighbouring Djankuat Glacier, one of 10 reference glaciers in the world. Located south of the meganticlinorium axis, the boring site is characterized by glacier budget improvement during the last decades similar to the northern slope – less rapidly until the 1980s and more rapidly since.     

Landslide Activity Maps for Landslide Hazard Evaluation: Three Case Studies from Southern Italy

This paper focuses on the application of landslideactivity maps for evaluating the mass movementhazard in selected areas of the Southern Apenninesof Italy: Bisaccia, Calitri, and Buoninventre. Theavailability of multi-year aerial photo coveragehelped to assess the morphological changes whichoccurred in the last 40 years. This information,integrated with historical data on slope instabilityand field checks, were used to produce landslideactivity maps. These maps represent a short-cut inthe assessment of mass movement hazard, because theyfocus on the effects of slope instability ratherthan on the causative conditions and processes;however, if kept simple and prepared at large scale,they may help the local administrators and land-useplanners to reduce the socio-economic costs oflandslides. Furthermore, the comparative study oflandslide activity represents a relativelyinexpensive and quick method for evaluating theperformance of the engineering control efforts.The quantification of landslide activity in terms ofareal frequency can represent an additional step,useful to determine the relative landslide hazard(zonation in more or less hazardous areas). Forexample, the estimates of areal frequency of activelandsliding for the last 40 years demonstrated thegreat influence of the 1980 Irpinia earthquake(M_s = 6.9) on the stability of slopes situatedclose to its epicenter (within a radius of about20 km).     

新疆境外震中参考地名查询实现

震中参考地名的确定是地震速报工作不可缺少的环节,在Google地图中以KML格式提取和存储新疆周边国家和地区边界坐标数据,利用Delphi语言和天地图API相关技术,开发新疆境外震中参考地名的查询软件,从而可以快速确定新疆周边国家和地区的参考地名,使得境外地震速报的地名准确性和速度得到明显提高。