fx-4800P型计算器坐标变换程序

用CASIO fx-4800P型可编程计算器进行经纬度、3°带和6°带坐标转换应用程序实现了用使用率较高的普通编程计算器进行一般精度要求的高斯投影面坐标转换的计算,文章介绍了该应用程序及其计算精度和使用方法.     

广西壮族自治区正轴等角割圆锥投影

根据地图投影选择的原则以及广西壮族自治区的地理位置和形状 ,设计了广西壮族自治区正轴等角割圆锥投影。它的两条标准纬线分别为φ1 =2 2°0 0′,φ2 =2 5°30′,投影常数α=0 .40 2 810 6 0 7,K =17195 30 6 .82 ,面积变形在南北边缘仅为 +2‰ ,在制图区域中部为 - 1‰ ,面积变形很小。因此 ,本投影可以作为编制广西壮族自治区地图的数学基础。     

多源GIS高斯投影快速换带算法研究

说明快速换带在多源GIS中的重要作用。介绍正反算法，正形变换法，仿射变换法和相似变换法等4种坐标变换算法，发现并改正文献[5]中的公式错误，从控制点个数，误差分布和速度等方面考虑，用正形变换法，仿射变换法和相似变换法进行了对比研究，找出一种最适合快速换带的算法-相似变换法，在研究中发现正形变换法在进行高斯投影换带时既有精度最佳区域又有精度异常区域存在。     

大型遥感影像数据库的空间无缝数据组织

分析了我国数字正射影像产品的空间参考特性和建立大型无缝影像数据库所带来的问题，在此基础上提出了海量影像数据管理中分带存储模式和跨带漫游算法，实践证明了用这种管理方式来建立省级或国家级无缝影像数据库的科学性、有效性和实用性。     

地图投影在地理信息系统中的应用

GIS以表示地理信息的数据库为核心 ,以同时描述空间数据和属性数据为最基本的特征。将不同尺度、不同时期、不同来源的地理数据精确定位于公共的地理基础之上 ,是实现GIS目标的基本要求。不同投影之间的互相转换以及投影类型或参数的选择对GIS数据的输出结果有极大影响。本文通过对地图投影的分类、经纬线特征、变形分布的分析 ,探讨了GIS中地图投影的变换和选择方法     

Photogrammetric measurement of patients in radiotherapy

The correct positioning of the patient is an important demand in radiotherapy. Optical measurements seem appropriate, but special requirements of speed and accuracy must be met. A new photogrammetric system that captures patient surface data in real-time is introduced. It allows reproducible patient set-up, and monitors the patient's position during irradiation even when the patient is moving. It consists of two cameras and one projector and is based on the photogrammetric evaluation of stereo image pairs by projecting white light fringes onto the patient's body.The raw data of the 3D measurement is a sequence of point clouds. It can be evaluated together with other data modes common in radiotherapy for diagnosis and treatment planning. The system can be used as an additional verification tool for the correct positioning of the patient, and completely new applications emerge.     

南极地区常用地图投影及其应用

南极地区常用的地图投影方式有 :极方位立体投影、横轴墨卡托投影、兰伯特正形圆锥投影等三种等角投影。本文在介绍了所有等角投影应满足的一般条件的基础上 ,分别详述了上述三种投影在南极地区的具体应用。并对卫星影像的投影作了探讨。     

基于任意椭球高斯坐标转换程序实现与精度分析

将高斯投影计算的原始公式编制成程序,并在程序中预先定义几个常用椭球以及它们的相关参数;同时将程序分为单点模式和批量模式,并打开一个自定义椭球接口来满足用户的需要。通过算例与工程应用软件南方CASS 8.0版本坐标换带模块进行对比分析,结果证明该程序是可靠的,能够满足日常测量工作的基本需要。     

Changes in Mean and Extreme Temperature and Precipitation over the Arid Region of Northwestern China:Observation and Projection

This paper reports a comprehensive study on the observed and projected spatiotemporal changes in mean and extreme climate over the arid region of northwestern China, based on gridded observation data and CMIP5 simulations under the RCP4.5 and RCP8.5 scenarios. The observational results reveal an increase in annual mean temperature since 1961, largely attributable to the increase in minimum temperature. The annual mean precipitation also exhibits a significant increasing tendency. The precipitation amount in the most recent decade was greater than in any preceding decade since 1961. Seasonally,the greatest increase in temperature and precipitation appears in winter and in summer, respectively. Widespread significant changes in temperature-related extremes are consistent with warming, with decreases in cold extremes and increases in warm extremes. The warming of the coldest night is greater than that of the warmest day, and changes in cold and warm nights are more evident than for cold and warm days. Extreme precipitation and wet days exhibit an increasing trend, and the maximum number of consecutive dry days shows a tendency toward shorter duration. Multi-model ensemble mean projections indicate an overall continual increase in temperature and precipitation during the 21 st century. Decreases in cold extremes, increases in warm extremes, intensification of extreme precipitation, increases in wet days, and decreases in consecutive dry days, are expected under both emissions scenarios, with larger changes corresponding to stronger radiative forcing.