全文获取类型
| 收费全文 | 430篇 |
| 免费 | 9篇 |
| 国内免费 | 14篇 |
专业分类
| 测绘学 | 336篇 |
| 大气科学 | 16篇 |
| 地球物理 | 19篇 |
| 地质学 | 25篇 |
| 海洋学 | 23篇 |
| 天文学 | 20篇 |
| 综合类 | 9篇 |
| 自然地理 | 5篇 |
出版年
| 2022年 | 3篇 |
| 2021年 | 12篇 |
| 2020年 | 9篇 |
| 2019年 | 7篇 |
| 2018年 | 4篇 |
| 2017年 | 31篇 |
| 2016年 | 22篇 |
| 2015年 | 18篇 |
| 2014年 | 22篇 |
| 2013年 | 25篇 |
| 2012年 | 30篇 |
| 2011年 | 24篇 |
| 2010年 | 19篇 |
| 2009年 | 25篇 |
| 2008年 | 26篇 |
| 2007年 | 30篇 |
| 2006年 | 40篇 |
| 2005年 | 13篇 |
| 2004年 | 15篇 |
| 2003年 | 20篇 |
| 2002年 | 10篇 |
| 2001年 | 8篇 |
| 2000年 | 7篇 |
| 1999年 | 3篇 |
| 1998年 | 7篇 |
| 1997年 | 2篇 |
| 1996年 | 3篇 |
| 1995年 | 4篇 |
| 1994年 | 8篇 |
| 1993年 | 1篇 |
| 1991年 | 2篇 |
| 1990年 | 1篇 |
| 1987年 | 1篇 |
| 1986年 | 1篇 |
排序方式： 共有453条查询结果，搜索用时 15 毫秒
381.
A combined single range and single image device for low-cost measurement of building façade features
Celestino Ordóñez Pedro Arias José Herráez Jaime Rodríguez María T. Martín 《The Photogrammetric Record》2008,23(122):228-240
The dimensions of building façades and window apertures are usually determined by making direct measurements using tapes and plummets. This approach, however, has a number of drawbacks including the physical risk to which the persons making the measurements are exposed. This paper proposes an indirect approach based on close range photogrammetry that is inexpensive, simple, fast and safe, and which does not require specialist staff or direct ground control measurements. The method is based on taking a picture using a digital camera and measuring the distance to the object using a handheld laser distance meter. Both items of equipment are mounted on a specially designed support that allows the laser distance meter to move independently of the camera. 相似文献
382.
李卉 《测绘与空间地理信息》2017,40(5)
利用小型多旋翼无人机搭载单镜头微单相机,从低空快速获取地物的三维信息,来满足城市快速发展对数据获取的需求,并提出一种新的纠正方法对优选的纹理进行纠正,重新赋予像点灰度值。实验结果表明,经过纠正后的纹理图像能够用来对三维模型进行构建。 相似文献
383.
近年来无人机在航空摄影测量中得到广泛应用,且多面阵宽角组合相机与单相机作业模式相比有诸多优势。针对无人机搭载的组合宽角五相机的影像处理问题,提出了实现大像幅影像拼接的方法与技术流程。通过在子影像重叠区域内建立视差方程,采用最小二乘法整体答解相对角元素修正量,最终得到精确的相对角元素值并作为影像的拼接参数,实现了多面阵组合五相机的影像拼接。 相似文献
384.
提出了基于大比例尺航空影像共面约束的相机自检校方法,该方法使用所有立体像对同名点基于共面约束对相机的内方位元素及畸变系数进行解算。首先进行航空影像同名点匹配,构建立体像对;然后基于共面约束使用直接解法和迭代优化进行相对定向,解算相机位置与姿态;最后使用最小二乘优化方法解算相机内方位元素和畸变系数。对于高分辨率大尺寸航空影像,图像中心及边缘的畸变差异较大,为了进一步提高解算精度,对图像进行网格区域划分解算畸变。使用大比例尺航空影像进行解算能真实精确反映航空摄影测量时所获取图像的相机参数和畸变系数,避免检校环境与使用环境不同解算得到的相机畸变参数不能真实反映所获取影像的畸变问题;使用所有同名点解算,避免由于选择不同特征点或控制点对检校精度的影响;通过区域网格划分,进一步提高了解算精度。对检校结果进行了分析,该方法精度较高,与基于室外检校场的精度相当,能真实精确反映航空摄影测量时所获取图像的相机参数和畸变系数,提高了三维重建的精度。 相似文献
385.
The spectral reflectance of most plant species is quite similar, and thus the feasibility of identifying most plant species based on single date multispectral data is very low. Seasonal phenological patterns of plant species may enable to face the challenge of using remote sensing for mapping plant species at the individual level. We used a consumer-grade digital camera with near infra-red capabilities in order to extract and quantify vegetation phenological information in four East Mediterranean sites. After illumination corrections and other noise reduction steps, the phenological patterns of 1839 individuals representing 12 common species were analyzed, including evergreen trees, winter deciduous trees, semi-deciduous summer shrubs and annual herbaceous patches. Five vegetation indices were used to describe the phenology: relative green and red (green\red chromatic coordinate), excess green (ExG), normalized difference vegetation index (NDVI) and green-red vegetation index (GRVI). We found significant differences between the phenology of the various species, and defined the main phenological groups using agglomerative hierarchical clustering. Differences between species and sites regarding the start of season (SOS), maximum of season (MOS) and end of season (EOS) were displayed in detail, using ExG values, as this index was found to have the lowest percentage of outliers. An additional visible band spectral index (relative red) was found as useful for characterizing seasonal phenology, and had the lowest correlation with the other four vegetation indices, which are more sensitive to greenness. We used a linear mixed model in order to evaluate the influences of various factors on the phenology, and found that unlike the significant effect of species and individuals on SOS, MOS and EOS, the sites' location did not have a direct significant effect on the timing of phenological events. In conclusion, the relative advantage of the proposed methodology is the exploitation of representative temporal information that is collected with accessible and simple devices, for the subsequent determination of optimal temporal acquisition of images by overhead sensors, for vegetation mapping over larger areas. 相似文献
386.
387.
388.
随着网络通信、三维建模和地理信息等各项技术的进步,基于Web的三维GIS应用需求越来越广泛。本文融合了Html5、JavaScript、WebGL、MongoDB和倾斜摄影建模等技术,利用这些技术的优势,实现了基于Web的三维GIS应用,为Web三维GIS应用提供了新的实现方式,使得三维数据更具有时效性,三维数据实现跨平台浏览,用户体验更好。 相似文献
389.
The Arctic is experiencing disproportionate warming relative to the global average, and the Arctic ecosystems are as a result undergoing considerable changes. Continued monitoring of ecosystem productivity and phenology across temporal and spatial scales is a central part of assessing the magnitude of these changes. This study investigates the ability to use automatic digital camera images (DCIs) as proxy data for gross primary production (GPP) in a complex low Arctic wetland site. Vegetation greenness computed from DCIs was found to correlate significantly (R2 = 0.62, p < 0.001) with a normalized difference vegetation index (NDVI) product derived from the WorldView-2 satellite. An object-based classification based on a bi-temporal image composite was used to classify the study area into heath, copse, fen, and bedrock. Temporal evolution of vegetation greenness was evaluated and modeled with double sigmoid functions for each plant community. GPP at light saturation modeled from eddy covariance (EC) flux measurements were found to correlate significantly with vegetation greenness for all plant communities in the studied year (i.e., 2010), and the highest correlation was found between modeled fen greenness and GPP (R2 = 0.85, p < 0.001). Finally, greenness computed within modeled EC footprints were used to evaluate the influence of individual plant communities on the flux measurements. The study concludes that digital cameras may be used as a cost-effective proxy for potential GPP in remote Arctic regions. 相似文献
390.