排序方式： 共有304条查询结果，搜索用时 15 毫秒
171.
Google Earth和World Wind比较研究 总被引：9，自引：0，他引：9
Google Earth和World Wind是目前最具代表性的两款基于网络的三维地理信息浏览器,为空间信息的共享发布提供了新的解决思路和技术手段。本文首先深入分析了这两款软件的技术特点,并在此基础上作了比较研究。 相似文献
172.
Morphological analysis of landforms has traditionally relied on the interpretation of imagery. Although imagery provides a natural view of an area of interest (AOI) images are largely hindered by the environmental conditions at the time of image acquisition, the quality of the image and, mainly, the lack of topographical information, which is an essential factor for a correct understanding of the AOI's geomorphology. More recently digital surface models (DSMs) have been incorporated into the analytical toolbox of geomorphologists. These are usually high‐resolution models derived from digital photogrammetric processes or LiDAR data. However, these are restricted to relatively small areas and are expensive or complex to acquire, which limits widespread implementation. In this paper, we present the multi‐scale relief model (MSRM), which is a new algorithm for the visual interpretation of landforms using DSMs. The significance of this new method lies in its capacity to extract landform morphology from both high‐ and low‐resolution DSMs independently of the shape or scale of the landform under study. This method thus provides important advantages compared to previous approaches as it: (1) allows the use of worldwide medium resolution models, such as SRTM, ASTER GDEM, ALOS, and TanDEM‐X; (2) offers an alternative to traditional photograph interpretation that does not rely on the quality of the imagery employed nor on the environmental conditions and time of its acquisition; and (3) can be easily implemented for large areas using traditional GIS/RS software. The algorithm is tested in the Sutlej‐Yamuna interfluve, which is a very large low‐relief alluvial plain in northwest India where 10 000 km of palaeoriver channels have been mapped using MSRM. The code, written in Google Earth Engine's implementation of JavaScript, is provided as Supporting Information for its use in any other AOI without particular technical knowledge or access to topographical data. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
173.
Since the collapse of the Soviet Union, the crop cultivation structure in the Aral Sea Basin has changed dramatically, and these changes are worth studying. However, historical crop remote sensing mapping at the watershed scale remains challenging, especially crop misclassification at the cropland edge due to mixed pixels. Therefore, we proposed a field segmentation approach to constrain field edges based on time-series Sentinel-2 remote sensing images and the Google Earth Engine platform and then employed the random forest algorithm to perform crop classification based on time series Landsat/Sentinel-2 images and crop phenology information to produce historical crop maps in the Aral Sea Basin from the 1990s onward. The results showed that the intersection over union between the extracted field edges and in situ-measured field size data was 0.65. The overall accuracy of crop mapping was 95.2% in 2019. Then, we extended our method to historical mapping over the 1991–2015 period with accuracies ranging from 82.8% to 91.3%. Moreover, our method applied to historical mapping works well in terms of accuracy and policy matching. These findings indicate that our method can accurately distinguish cropland edges to reduce classification errors due to mixed pixels. This method is promising for solving the cropland edge problem for historical crop mapping in the Aral Sea Basin and can potentially provide a reference for historical crop classification in other watersheds of the world. 相似文献
174.
The use of freely-available multi-source imagery for mapping vegetation in montane terrain is important for many developing countries that do not have the funding for high-resolution data capture. Radar images are also now freely available and include Sentinel-1 in dual polarisation, and PALSAR-2. These images can penetrate cloud cover and provide the advantage of acquiring data in a cloudy tropical region. This research evaluated whether the addition of radar with optical and topographic data improves classification accuracy in a montane region in Sri Lanka. Six classification experiments were designed based on different combinations of image data to test whether radar data improved land cover classification accuracy compared with optical data alone. Random forest classifier in the Google Earth Engine has been utilised to classify the tropical montane vegetation. The results indicate that radar or optical data alone cannot obtain satisfactory results. However, when combining radar with optical data the overall accuracy increased by approximately 5%, and by an additional 2% when topography data were added. The highest accuracy (92%) was achieved with multiple imagery, and adding the vegetation indices improved the model slightly by 0.3%. In addition, feature importance analysis showed that radar data makes a significant contribution to the classification. These positive outcomes demonstrate that freely-accessible multi-source remotely-sensed data have impressive capability for vegetation mapping, and support the monitoring and managing of forest ecological resources in tropical montane regions. 相似文献
175.
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。 相似文献
176.
We reply to Gwilym Eades’s (2010) criticisms by emphasizing the dangers of predestined readings and restating three key points that we made in our previous article (Kingsbury and Jones, 2009): first, that Apollo and Dionysus are mutually affirming rather than oppositional; second, that Walter Benjamin provides valuable theoretical resources to consider the uncertainties and possibilities of technology; and third, that one cannot simply read politics off technology. 相似文献
177.
基于Google Maps API和网络数据抓取技术的WebGIS开发 总被引：2，自引：0，他引：2
Web地图服务已经成为网站构建者所青睐的一项服务.从大的门户网站,如搜狐、雅虎等,到小型的博客站点,其应用范围越来越广.以Google Maps API和网络数据抓取技术为基础,研究WebGIS数据共享与利用的有效方法,并给出一个详细的开发实例. 相似文献
178.
Jamie Woodward 《地球表面变化过程与地形》2015,40(5):706-709
This commentary uses Google Books N‐grams to briefly explore the changing use of the word geomorphology in books published in British English and American English. Both show a decline in the use of the term geomorphology in recent years. A singular feature of the British data is a very sharp rise and fall in the use of term geomorphology in books published since 1980. The steep falling limb (post 1993) of this curve is of particular concern and several possible explanations are put forward including, since 1986, the influence exerted by Research Assessment Exercises on publication practice in UK universities. The N‐gram trends pose important questions for all geomorphologists and we should monitor them to gain a better understanding of where we need to be most visible to ensure the long‐term health of our discipline. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
179.
BIM通过数字信息仿真模拟建筑物所具有的真实信息,是近年来国际上工程领域的新型建模技术,逐渐得到广泛应用。本文基于Google SketchUp建立某声学风洞BIM模型,并将其应用于风洞施工过程中的高精度测量工作中。通过研究BIM模型应用于测量的方法,实现了大规模三维测设数据的获取以及大尺度全方位竣工测量误差分析,对于今后相关工程的顺利施工具有重要的参考价值。 相似文献
180.
针对三维地质建模工作繁琐、复杂,从手工绘制地质模型角度提出了一种基于GIS耦合SketchUp技术的三维地层模型绘制方法。采用钻孔资料作为数据源,通过ArcGIS的插值和栅格转换工具生成地层三角网格。然后利用SketchUp的封面插件和表面求交工具,生成地层的三维体模型。该方法操作简单、直观和易于掌握,具有一定的推广和应用价值。 相似文献