面向过程的时空数据模型研究   总被引：5，自引：0，他引：5  

薛存金  周成虎  苏奋振  董庆  谢炯 《测绘学报》2010,39(1):0-6

根据近20年来时空数据模型的研究现状、存在问题及其原因剖析,以连续渐变地理实体的表达、组织和存储为研究对象,提出面向过程的时空数据模型。根据连续渐变地理实体的内在特性,将其分级抽象为过程对象系列,进一步探讨过程对象及过程对象间逻辑关系,并设计其UML模型结构及物理存储结构。通过抽象的过程对象隐式地记录地理实体动态变化机制,及自定义的过程对象存储表提供演变机制的函数接口模式,实现连续渐变地理实体的过程化组织、存储与动态分析。最后,以海洋数据的过程化组织与分析为例,构建时空过程模型原型系统(海洋过程对象—关系数据库系统与功能分析平台),验证和评价该模型的实用性。  相似文献   

基于CQG2000的吉林省西部地区似大地水准面的建立     

刘振宇  高炳浩 《测绘学报》2010,39(5):441-443

针对CQG2000精度无法满足实际工作的情况，提出一种新的重力似大地水准面与GPS水准的拟合方法—残差模型法，利用CQG2000、较密集的GPS水准点，采用残差模型法建立吉林省西部地区似大地水准面模型（JiLin West Quasi-Geoid，JLWQG）。论述建立JLWQG的三角剖分双线性内插算法及其适用性，检测结果表明，JLWQG精度达到了±0.05m，JLWQG在吉林省西部地区基础测绘更新工作中进行了大面积的应用，取得了满意的结果。  相似文献   

导航应用的按需下载区域网络模型研究     

张林  曹彦荣 《测绘软科学研究》2010,(1):36-42

提出了一种导航应用的按需下载区域数据模型。对按需下载模式的技术要求进行了分析，提出了区域导航数据模型的定义及其算法，用UML定义了区域网络概念模型，并与ISO的网络模型进行了一致性检验。通过实际算例证明了方法的可用性。  相似文献   

基于笛卡尔坐标的卫星地影模型解析     

丁剑  瞿锋  卫志斌  李谦 《测绘科学》2010,35(1):39-40,43

卫星地影的精确计算对于卫星的电源设计、定轨和定姿等方面具有重要意义。本文通过基于地心的笛卡尔坐标系,从向量的角度描述了日、地、卫之间的几何关系,针对不同轨道高度的卫星分别利用圆柱形模型和圆锥形模型对其进出地影的时间和位置进行了解算和分析,同时给出了圆锥形模型的计算程序。  相似文献   

基于ECR与ECI星历数据的遥感影像定位     

程春泉  邓喀中  张继贤  孙钰珊 《测绘科学》2010,35(2):13-15

经典的共线方程中物方坐标系建立在地球表面,在航天摄影测量中,地面摄影测量坐标系的应用,增加了不同类型测量数据间联合处理的难度,限制了影像数据摄影测量处理的空间范围。本文介绍了基于视线方向的影像对地定位算法原理,并以此为基础建立了地心系下的航天影像摄影测量共线方程。针对地固地心系和空固地心系下星历数据的不同点,建立了基于两种地心系下星历数据的航天遥感影像定位严密模型,并对两种模型中偏流角处理的不同点进行了分析,最后给出了一个应用试验。  相似文献   

Accuracy improvement of ASTER stereo satellite generated DEM using texture filter     

Mandla V.Ravibabu  Kamal Jain  Surendra Pal Singh  Naga Jyothi Meeniga 《地球空间信息科学学报》2010,13(4):257-262

The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite images.Currently,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital photogrammetry.One of the most important steps in such deployment i...  相似文献   

Under‐ice salinity and stable isotope distribution of Saroma‐ko Lagoon,Hokkaido, northern Japan     

Maki Morimoto  Kyoko Kawanobe  Osamu Abe  Takayoshi Kawai  Toshiyuki Kawamura  Kunio Shirasawa 《水文研究》2010,24(7):904-916

In winter, lakes and lagoons at high altitudes or high latitudes have interesting hydrological cycles that differ from those in other seasons or in other regions, because water surfaces are covered with ice. Hydrological balances of lakes and lagoons are complex dynamic systems, and to elucidate them, isotopic tracers of water have been used as effective tools along with observations of precipitation, evaporation, inflows, and outflows. Here, to understand hydrological processes during freezing periods in the brackish Saroma‐ko Lagoon, Hokkaido, northern Japan, we examined horizontal and vertical distributions of salinity and isotope compositions of lagoon water and ice in 2005 and 2006. Horizontal and vertical gradients of salinity and isotope compositions were observed from the river mouth to the sea channel, and factors determining these distributions were considered. The mixing of freshwater and seawater and a freezing effect were presumed to be factors in relationships between salinity and isotopes and in relationships between surface waters and ice just above the water. A simple box model for water balance was constructed based on these putative factors to reproduce the distributions of salinity and isotope compositions of surface waters and ice. An evaluation of the model revealed that this hydrological system is controlled primarily by horizontal advection of the epilimnion, freshwater influx, and the ice growth rate. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Sensitivity of streamflow from a Himalayan catchment to plausible changes in land cover and climate     

Xing Ma  Jianchu Xu  Meine van Noordwijk 《水文研究》2010,24(11):1379-1390

Global climate change will likely increase temperature and variation in precipitation in the Himalayas, modifying both supply of and demand for water. This study assesses combined impacts of land‐cover and climate changes on hydrological processes and a rainfall‐to‐streamflow buffer indicator of watershed function using the Soil Water Assessment Tool (SWAT) in Kejie watershed in the eastern Himalayas. The Hadley Centre Coupled Model Version 3 (HadCM3) was used for two Intergovernmental Panel on Climate Change (IPCC) emission scenarios (A2 and B2), for 2010–2099. Four land‐cover change scenarios increase forest, grassland, crops, or urban land use, respectively, reducing degraded land. The SWAT model predicted that downstream water resources will decrease in the short term but increase in the long term. Afforestation and expansion in cropland will probably increase actual evapotranspiration (ET) and reduce annual streamflow but will also, through increased infiltration, reduce the overland flow component of streamflow and increase groundwater release. An expansion in grassland will decrease actual ET, increase annual streamflow and groundwater release, while decreasing overland flow. Urbanization will result in increases in streamflow and overland flow and reductions in groundwater release and actual ET. Land‐cover change dominated over effects on streamflow of climate change in the short and middle terms. The predicted changes in buffer indicator for land‐use plus climate‐change scenarios reach up to 50% of the current (and future) range of inter‐annual variability. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

A simple model to estimate monthly forest evapotranspiration in Japan from monthly temperature     

Hikaru Komatsu  Tomonori Kume  Kyoichi Otsuki 《水文研究》2010,24(13):1896-1911

The estimation of evapotranspiration (E) in forested areas is required for various practical purposes (e.g. evaluation of drought risks) in Japan. This study developed a model that estimates monthly forest E in Japan with the input of monthly temperature (T). The model is based on the assumptions that E equals the equilibrium evaporation rate (E_eq) and that E_eq is approximated by a function of T. The model formulates E as E (mm month⁻¹) = 3·48 T ( °C) + 32·3. The accuracy of the model was examined using monthly E data derived using short‐term water balance (WB) and micrometeorological (M) methods for 15 forest sites in Japan. The model estimated monthly E more accurately than did the Thornthwaite and Hamon equations according to regression analysis of the estimated E and E derived using the WB and M methods. Although the model tended to overestimate monthly E, the overestimation could be reduced by considering the effect of precipitation on E. As T data are commonly available all over Japan, the model would be a useful tool to estimate forest E in Japan. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Impacts of uncertain river flow data on rainfall‐runoff model calibration and discharge predictions     

Hilary McMillan  Jim Freer  Florian Pappenberger  Tobias Krueger  Martyn Clark 《水文研究》2010,24(10):1270-1284

In order to quantify total error affecting hydrological models and predictions, we must explicitly recognize errors in input data, model structure, model parameters and validation data. This paper tackles the last of these: errors in discharge measurements used to calibrate a rainfall‐runoff model, caused by stage–discharge rating‐curve uncertainty. This uncertainty may be due to several combined sources, including errors in stage and velocity measurements during individual gaugings, assumptions regarding a particular form of stage–discharge relationship, extrapolation of the stage–discharge relationship beyond the maximum gauging, and cross‐section change due to vegetation growth and/or bed movement. A methodology is presented to systematically assess and quantify the uncertainty in discharge measurements due to all of these sources. For a given stage measurement, a complete PDF of true discharge is estimated. Consequently, new model calibration techniques can be introduced to explicitly account for the discharge error distribution. The method is demonstrated for a gravel‐bed river in New Zealand, where all the above uncertainty sources can be identified, including significant uncertainty in cross‐section form due to scour and re‐deposition of sediment. Results show that rigorous consideration of uncertainty in flow data results in significant improvement of the model's ability to predict the observed flow. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献