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461.
AutoCAD VBA是一种简单易上手的编程工具,通过设计批处理程序能显著提高作业效率。本文基于AutoCAD VBA平台进行程序设计,针对地形图生产中九宫格修改的具体问题,编程进行批量修改,在实践基础上形成一种基于AutoCAD VBA的通用地形图批处理方法。实践证明,该方法能明显提高测绘生产部门的工作效率。 相似文献
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Several alternative estimation and interpolation methods for making annual precipitation maps of Asturias are analysed. The
data series in this study corresponds to the year 2003. There exists an evident relationship between precipitation and altitude,
with a high correlation coefficient of 0.70, that reflects the hillside effect; that is, the increase in the amount of precipitation
in more mountainous areas. The direct spatial variability of precipitation and of altitude and the cross variability of precipitation–altitude
are defined by two exponential variogram models: one with a short-range structure (15–30 km) that reflects the control exerted
by the lesser, local mountain ranges over the amount of precipitation; and another with a long-range structure (80 km) that
supposes the influence over precipitation of the major mountainous alignments of the inland areas of the Cantabrian Mountain
Range (Cordillera Cantábrica) situated between 60 and 90 km from the coastline. These variogram models had to be validated for coregionalization by the
Pardo-Igúzquiza and Dowd method so as to be able to make the cokriging map. The geometric estimation methods employed were
triangulation and inverse distance. The geostatistical estimation methods developed were simple kriging, ordinary kriging,
kriging with a trend model (universal kriging), lognormal kriging, and cokriging. In all of these methods, a 3 × 3 km2 grid was selected with a total of 2580 points to estimate, a circular search window of 60 km, and a relatively small number
of samples with the aim of highlighting the local features and variations on isohyet maps. The kriging methods were implemented
using the WinGslib software, incorporating two specific programs, Prog2 and Fichsurf, so as to be able then to make isohyet
maps using the Surfer software. All the methods employed, apart from triangulation, rendered realistic maps with good fits
to the values of the original data (precipitation) of the sample maps. The problem with triangulation lies not in the reliability
of the estimates but in the fact that it gives rise to contrived maps because of the tendency of isohyets to present abundant
triangular facets. The reliability of the methods was based on cross-validation analysis and on evaluation of the different
types of errors, both in their values and in their graphical representations. Substantial differences were not found in the
values of the errors that might discriminate some methods from others in an evident way. Bearing the aforesaid in mind, should
we have to make an evaluation of the different estimation methods in decreasing order of acceptance, this would be: kriging
with a trend model, inverse distance, cokriging, lognormal kriging, ordinary kriging, simple kriging, and triangulation. The
application of other estimation methods such as colocated cokriging, kriging with an external drift, and kriging of variable
local means (residual kriging) is dependent on the availability of a digital model of the terrain with an altitude grid of
the region. 相似文献
464.
以基于ArcGIS的电子地图制为研究对象,探讨了在地理信息公共服务平台中进行电子地图制作的技术流程及方法,详细阐述了电子地图制作中的数据提取,数据组织与电子地图数据展示中的相关关键技术,实现了地理信息公共服务平台在线地图展示、浏览和标注。 相似文献
465.
Sébastien Caquard 《The Cartographic journal》2014,51(2):101-106
AbstractThis paper provides an overview of the multiple ways of envisioning the relationships between maps and narratives. This is approached from a map making perspective. Throughout the process of editing this special issue, we have identified two main types of relationships. Firstly, maps have been used to represent the spatio-temporal structures of stories and their relationships with places. Oral, written and audio-visual stories have been mapped extensively. They raise some common cartographic challenges, such as improving the spatial expression of time, emotions, ambiguity, connotation, as well as the mixing of personal and global scales, real and fictional places, dream and reality, joy and pain. Secondly, the potential of maps as narratives and the importance of connecting the map with the complete mapping process through narratives is addressed. Although the potential of maps to tell stories has already been widely acknowledged, we emphasize the increasing recognition of the importance of developing narratives that critically describe the cartographic process and context in which maps unfold - the core idea of post-representational cartography. Telling the story about how maps are created and how they come to life in a broad social context and in the hands of their users has become a new challenge for mapmakers. 相似文献
466.
不同Klobuchar模型参数的性能比较 总被引:3,自引:1,他引:2
对于GPS单频用户而言,电离层延迟是最重要的误差来源之一。GPS系统使用Klobuchar模型对电离层延迟进行改正,其改正数从370组常数中选取。目前全球分布的GPS测站可以获得高精度的全球电离层监测结果,GPS为什么不发播采用实测数据计算得到的Klobuchar模型参数呢?本文针对这一问题进行分析。首先对欧洲定轨中心CODE提供的全球电离层图GIM预报COPG电离层进行精度评估,然后根据COPG电离层进行Klobuchar模型参数拟合并利用IGS提供的事后高精度电离层图进行精度分析,最后将不同的电离层模型参数应用于单点定位以评估其对单频用户的影响。分析结果表明:受8参数的Klobuchar模型本身结构限制,采用全球实测数据计算的电离层模型参数与导航电文中发播的电离层模型精度相当,为55%左右。而仅采用地磁纬度45oS以北的数据拟合得到的模型参数,其电离层改正精度有明显提升,可达65%左右,但其对单频用户定位精度改善不明显。本文研究结果为我国全球电离层建模提供参考。 相似文献
467.
随着智能移动终端的极大流行,通过将传统的纸质地图(集)制作成智能移动终端(如iPad)上的电子地图(集),能够更灵活地提供地图服务。本文主要探讨iPad中可阅读的两种格式(ePub与PDF)的电子地图(集),介绍了其制作技术路线和方法,以及iPad电子地图(集)典型的导入方法。 相似文献
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470.
Lucia Maria Seebach Peter Strobl Jesus San Miguel-Ayanz Annemarie Bastrup-Birk 《International journal of geographical information science》2013,27(11):1865-1884
Detailed and harmonized information on spatial forest distribution is an essential input for forest-related environmental assessments, in particular, for biomass and growing stock modeling. In the last years, several mapping approaches have been developed in order to provide such information for Europe in a harmonized way. Each of these maps exhibits particular properties and varies in accuracy. Yet, they are often used in parallel for different modeling purposes. A detailed spatial comparison seemed necessary in order to provide information on the advantages and limitations of each of these forest cover maps in order to facilitate their selection for modeling purposes. This article confronts the high-resolution forest cover map recently developed by the Joint Research Centre for the year 2000 (FMAP2000) with previously existing maps for the same time period: the CORINE Land Cover 2000 (CLC2000) and the Calibrated European Forest Map 1996 (CEFM1996). The spatial comparison of these three maps was carried out based on forest proportion maps of 1 km derived from the original maps. To characterize differences according to biogeographic regions, two criteria were used: detail of thematic content within each map and local spatial agreement. Concerning thematic content, CLC2000 displayed a surfeit of non-forested areas at the cost of low forest proportions, while FMAP2000 showed a more balanced distribution likely to preserve more detail in forest spatial pattern. Good spatial agreement was found for CLC2000 and FMAP2000 within about 70% of the study area, while only 50% agreement was found when compared with CEFM1996. The largest spatial differences between all maps were found in the Alpine and Mediterranean regions. Reasons for these might be different input data and classification techniques and, in particular, the calibration of CEFM1996 to reported national statistics. 相似文献