共查询到20条相似文献，搜索用时 31 毫秒
1.
SHI XiaoyanHU YujuLU XiangdongSHI Xiaoyan Lecturer School of Land Science WTUSM Wuhan China 《地球空间信息科学学报》1998,(1)
A geometric algorithm for Tilted-Camera Perspective（TCP）projec-tion is proposed in this paper based on the principle of perspective projection.Ac-cording to that,the difference between TCP projection and External Perspective（EXP）projection is analyzed.It is put forward prerequisites making these twoprojections were compatible,and some examples are given. 相似文献
2.
本文根据透视投影的基本原理，给出了关于倾斜相机式投影的几何解法，在此基础上分析了倾斜相机式投影与外心投影的异同，提出了二者比较的一致性条件，并给出了实例验证。 相似文献
3.
对翻译出版书中遗留未能译出的“Freyen”予以澄清；所涉及的书名，得到更正。二百多年前，兰伯特在该书中提出的“透视反转”，可视为像片纠正的理论根据。透视反转作图的主要步骤是找现投影中心和确定透视轴的位置。文中所引用的图1、图2，详细地说明了确定相应投影中心的步骤。对确定透视轴的位置，提出了图解的方法。 相似文献
4.
5.
AbstractI. Introduction.—Map projection is a branch of applied mathematics which owes much to J. H. Lambert (v. this Review, i, 2, 91). In his “Beyträge zum Gebrauche der Mathematik und deren Anwendung” (Berlin, 1772) he arrived at a form of projection whereof the Transverse Mercator is a special case, and pointed out that this special case is adapted to a country of great extent in latitude but of small longitudinal width. Germain (“Traité des Projections”, Paris, 1865) described it as the Projection cylindrique orthomorphe de Lambert, but he also introduced the name Projection de Mercator transverse or renversée; he shows that Lambert's treatment of the projection was remarkably simple. 相似文献
6.
《测量评论》2013,45(20):354-358
Abstract 6. Further Expansions.—Equations (4.3) and (5.5) enable a computer to transform coordinates from the Cassini projection to the Gauss projection without recourse to geographical coordinates. If applied to one or two points, no doubt these equations would be quite satisfactory; but if applied to 100,000 points their use would be laborious and it would be difficult to adapt them to machine computing. 相似文献
7.
《测量评论》2013,45(32):66-67
AbstractThe projection in question is a mean between Mercator's and the Equal-Area Cylindrical Projection which is formed by orthographic projection from the sphere upon the circumscribing cylinder. Both projections are computed on the spherical assumption. Mercator's Projection is, of course, the best known of the orthomorphic group; the Equal-Area Cylindrical Projection is the simplest of the equal-area group. Each projection may be said to represent an extreme case; and the mean between them may perhaps, for some purposes, be a useful compromise. 相似文献
8.
《测量评论》2013,45(72):90-92
AbstractWhen developing the argument leading to the stereographic solution of the spherical triangle and its application to field astronomy (Empire Survey Review, Vol. 2, No. 10, October, 1933, p. 226) A. J. Potter rendered a very useful service in demonstrating how proofs of the two practically useful properties of the stereographic projection can be provided along lines that demand no more than simple geometry in their development. The proof advanced for the unique property that any circle on the. sphere remains a circle in projection is at once simple and complete; but in the attempt to prove that the projection is orthomorphic in the sense that angles everywhere remain true there is the difficulty that the argument was developed for what must be regarded as a special case in that the point was located on the great circle through the origin of the projection normal to the plane of the projection. Treatment of the problem along similar lines for other points away from the central meridian does not seem to admit of such ready solution and the alternative approach suggested here, while still not demanding. anything beyond simple geometry for its understanding, affords a proof for a general case. 相似文献
9.
《测量评论》2013,45(18):236-241
AbstractI. Introduction.-For some little time the Ordnance Survey was engaged upon the problem of transforming the rectangular coordinates of trigonometrical stations from the Cassini projection to the Gauss Conformal projection. The problem was complicated by the fact that the Cassini projection, as is well known, was applied to a number of meridians of origin, a different meridian being used for a county or a group of counties. It was proposed, however, to have only one meridian for the Gauss projection and to drop the county meridians completely. In both projections the northings were measured from the same parallel. 相似文献
10.
11.
Steven E. Greco 《地球空间信息科学学报》2013,16(4):288-293
ABSTRACTConceptually, the theory and implementation of “map projection” in geographic information system (GIS) technology is difficult to comprehend for most introductory students and novice users. Compounding this difficulty is the concept of a “map projection file” that defines map projection parameters of geo-spatial data. The problem of the “missing projection file” appears ubiquitous for all users, especially in practice where data is widely shared. Another common problem is inadvertent misapplication of the “Define Projection” tool that can result in a GIS dataset with an incorrectly defined map projection file. GIS education should provide more guidance in differentiating the concepts of map projection versus projection files by increasing understanding and minimizing common errors. A novel pedagogical device is introduced in this paper: the seven possible states of GIS data with respect to map projection and definition. The seven possible states are: (1) a projected coordinate system (PCS) that is correctly defined, (2) a PCS that is incorrectly defined, (3) a PCS that is undefined, (4) a geographic coordinate system (GCS) that is correctly defined, (5) a GCS that is incorrectly defined, (6) a GCS that is undefined, and (7) a non-GCS. Recently created automated troubleshooting tools to determine a missing map projection file are discussed. 相似文献
12.
本文较全面地研究了地图集投影系统的设计方法。包括系统论的引用；适用于地图集投影系统设计的新的地图集分类；地图集投影系统设计思想与步骤；地图集投影系统设计方法的发展趋势等内容。 相似文献
13.
《测量评论》2013,45(60):221-227
AbstractIn a previous article in this Review, the writer endeavoured to show that chains of minor triangulation could be adjusted by plane rectangular co-ordinates ignoring the spherical form of the earth with little loss of accuracy, provided that the two ends were held fixed in position. It was demonstrated that the plane co-ordinates produced by the rigorous adjustment between the fixed starting and closing sides, differ by only a comparatively small amount from the projection co-ordinates produced by a rigorous adjustment on the Transverse Mercator projection. The saving in time when computing by plane co-ordinates as opposed to rigorous computation on the projection by any method will be apparent to any computer with experience of both methods. 相似文献
14.
AbstractWhen computing and adjusting traverses or secondary and tertiary triangulation in countries to which the Transverse Mercator projection has been applied, it is often more convenient to work directly in terms of rectangular co-ordinates on the projection system than it is to work in terms of geographical coordinates and then convert these later on into rectangulars. The Transverse Mercator projection is designed in the first place to cover a country whose principal extent is in latitude and hence work on it is generally confined to a belt, or helts, in which the extent of longitude on either side of the central meridian is so limited as seldom to exceed a width of much more than about 200 miles. 相似文献
15.
16.
广西壮族自治区正轴等角割圆锥投影 总被引：1，自引：0，他引：1
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。 相似文献
17.
18.
《测量评论》2013,45(32):85-89
AbstractThe necessity of transforming rectangular co-ordinates from one system of projection to another may arise from, various causes, One case, for example, with which the present writer is concerned involves the transformation, to the standard belt now in use, of the co-ordinates of some hundreds of points of a long existing triangulation projected a quarter of a, century ago on a, belt of Transverse Mercator projection, In this case conversion is complicated by the fact that the spheroid used in the original computation differs from that now adopted, and, also, the geodetic datums are not the same, The case in fact approaches the most general that can occur in practice, One step in one solution of this problem, however, is of perhaps wider Interest: that is, the transformation from one belt of Transverse Mercator projection to another when the spheroids and datums are identical. It is this special case which will be discussed here. 相似文献
19.
20.
《测量评论》2013,45(58):142-152
AbstractIn January 1940, in a paper entitled “The Transverse Mercator Projection: A Critical Examination” (E.S.R., v, 35, 285), the late Captain G. T. McCaw obtained expressions for the co-ordinates of a point on the Transverse Mercator projection of the spheroid which appeared to cast suspicion on the results originally derived by Gauss. McCaw considered, in fact, that his expressions gave the true measures of the co-ordinates, and that the Gauss method contained some invalidity. He requested readers to report any flaw that might be discovered in his work, but apparently no such flaw had been detected at the time of his death. It can be shown, however, that the invalidities are in McCaw's methods, and there seems no reason for doubting the results derived by the Gauss method. 相似文献