A NUMERICAL METHOD FOR ORTHOGONAL GRID GENERATION BY LAPLACE SYSTEM

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建筑施工测量技术简析

针对施工测量,重点分析并解决了建筑物控制线、建筑物的竖向传递、建筑物的高程控制、沉降与垂直度的观测等问题。     

实对称矩阵空间的直交投影

在实对称矩阵空间建立了内积和范数 ,在由所有的半正定矩阵所组成的闭凸子集上定义了一种直交投影 ,并且讨论了它的一些性质和一个应用 .     

An Integrated Spatial Search Engine for Maps and Aerial Photographs on a Google Maps API Platform

A traditional library catalog does not do justice to maps and aerial photographs. Text can never fully describe them and maps' and aerial photographs' geographic coverage or perimeters cannot be displayed visually in the online public access catalog (OPAC), so searching based on their textual metadata without specific spatial reference data used also for display purposes is often not enough to locate relevant items. The Hebrew University of Jerusalem's (HUJI) Geography Department has developed a spatial search engine for their scanned aerial photographs collection that allows users to locate one or more aerial photographs according to the area of the Earth's surface that was photographed and their accompanying metadata. The Humanities and Social Sciences Library, which holds a large unscanned print map collection, has asked to integrate a similar map search mechanism in the Department's existing search engine, and a new website was launched in December 2015 (http://ccg.huji.ac.il/aerialphotos/) showing the aerial photographs' center points alongside the maps' rectangle perimeter. The search engine retrieves maps and aerial photographs that intersect with a user-drawn rectangle. This article discusses the characteristics of these collections, the rationale behind searching for maps and aerial photographs together, and the process of defining and building this spatial search engine. This method allows users to view which items are available in their area of interest side-by-side, on a Google Maps background map.     

极坐标法在圆锥曲线中的运用

结合实例，阐述了极坐标法在圆锥曲线中的运用.     

极坐标系下使用微元法需要注意的一个问题

分析定积分微元法中微元的条件,并通过讨论极坐标情形下求平面图形面积和平面曲线弧长这两个实例说明使用微元法的关键.     

三维运动分析中定标问题的简化模型

在三维运动分析中,从分析直接线性变换算法(DLT模型)对单摄像机和双摄像机的标定方程出发,利用坐标转换方法得出一种简单适用的简化模型,为解决实践中快速确定三维运动空间坐标问题提供理论分析依据。     

关于标注圆心坐标并列表的实现与AutoLISP程序

文章介绍在AutoCAD中如何实现快速标注圆心坐标并列表。利用二次开发技术,运用AutoLISP程程、开发在AutoCAD实现快速标注圆心坐标并列表的新命令,从而提高AutoCAD的绘图效率和准确性。     

中西美术史中的“坐标”

美术史意义上的坐标,不是地理学上用以指明方位的概念,而是指美术史特定美术现象、美术人物、美术活动、美术成果的时空位置。中西方美术史中的坐标问题,反映了中西方美术史述作在描述阐释定义各自时空美术发展过程中存在的差异性。     

Snippets of physics

It is well known in Newtonian gravity that a spherically symmetric density distribution produces a force outside it which falls as the square of the distance. Surprisingly, the converse is not true! Just be cause the force falls as inverse square outside a density distribution, you cannot conclude that it must be spherically symmetric. This article, first in a new series, explores this and related issues. This is based on an article originally published by the author in Physics Education, Vol 22, No. 4, p.263, 2006. T Padmanabhan works at IUCAA, Pune and is interested in all areas of theoretical physics, especially those which have something to do with gravity.