共查询到20条相似文献,搜索用时 809 毫秒
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主要介绍利用Microsoft Visual Basic.NET编写的地形图分幅编号查询与面积计算程序。通过该程序,根据经纬度坐标或高斯坐标,可查询该点所在各种基本比例尺下的图幅编号、西南图廓点的经纬度坐标以及在不同坐标系下的图幅面积。 相似文献
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一、说明国家基本比例尺地形图采用梯形分幅,并将高斯投影作为它的数学基础。过去计算图廓点坐标、图廓边长、图幅面积等常用查表方法,即使使用计算机,一般也需手工计算图廓点地理坐标,指定投影带中央经线经度等。用本文提到的这个程序,可在PC—1500袖珍计算机上,由图号直接计算出地形图图廓点的地理坐标、高斯投影直角坐标、图廓边长和图幅面积。对1:50万、1:25万、1:10万、1:5万、1:2.5万比例尺地形图在6°投影带上计算;而对1:1万、1:5千比例尺地形图则在3°投影带上计算。根据地形图图号,自动选择 相似文献
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采用3°带高斯投影直角坐标系的1:5000及1:2000,1:1000比例尺测图,其图幅按国际分幅法划分。在没有图廓点坐标表的情况下,可利用高斯—克吕格坐标表(纬度每5’一载,经差每7(1/2)’一载)之二万五千分之一地图图廓点坐标用下述方法逐次的插入各种大比例尺地图图廓点坐标,其精度亦能符合要求。现分述如下: 相似文献
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在同一本地图集中,除折页图幅外,一般标准图幅内图廓的尺寸都是一定的。图幅的比例尺扩大,包括的范围要缩小;图幅的比例尺缩小,包括的范围要扩大。某一幅图究竟包括多大范围、选定多大比例尺合适,在图集编辑设计中需要反复琢磨、反复调整。每幅图都临时粗略选定范围、计算出比例尺,凑整后精确计算出内图廓尺寸的大小,再在图上标出内图廓的具体位置,若觉得不合适还 相似文献
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大比例尺地图通常采用高斯-克吕格投影,标准分幅的地图图廓呈近似梯形。在应用中,一些专题地图,特别是专题地图集要求图廓为矩形,针对该需求,本文提出了一种高斯投影下地图矩形图廓坐标的计算方法,解决了矩形图廓不易计算的问题。实践证明,该方法能够满足精度需求,在专题地图制图中具有一定的价值。 相似文献
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在海量空间数据的组织与表达方面,与传统的空间数据模型与方法相比,地球剖分网格表现出了极大的优势。鉴此,本文提出了一种剖分网格下顾及用户兴趣的矢量地图多尺度表达方法,首先利用大量POI数据构建空间兴趣场模型,描述用户对地理信息的兴趣的空间分布;然后对空间要素进行分类分级,确定其表达的尺度范围;运用GeoSOT剖分理论划分不同层次的剖分面片,建立剖分面片与尺度的对应关系,根据用户对剖分面片所在区域的兴趣度大小,表达不同详细程度的空间要素,实现基于用户兴趣的空间数据多尺度表达。实验表明,该方法能够满足用户由概略到详细、由重要到次要的空间认知需求,同时能够获得较好的多尺度表达效果。 相似文献
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《测量评论》2013,45(75):218-227
AbstractThe oblique or general case of the gnomonic projection receives little serious attention in most text books on map projections and in the works which do include the theory it is unfortunately developed with unnecessary complexity. In consequence it is much less widely understood than are the special cases represented by the polar and equatorial forms. Yet the oblique form provides a gratieule which has proved incomparably more useful than either of the two Inore obvious and popular special cases. Thus, oblique cases have provided the graticules for the series of gnomonic charts of the oceans published by the Hydrographic Department of the Admiralty; the G.S.G.S. Consol Plotting Charts and the Gnomonic Fixing Chart (prepared specially for use with long range radio aids to navigation) are all oblique gnomonic graticules as are the special purpose charts for position fixing from radio bearings published by the Admiralty. In addition, all large scale port plans included in the range of Admiralty charts are drawn on a modified gnomonic. It is only in connection with the production of facets for “near globes” that one can point to the use of the polar and equatorial cases of the gnomonic and even here the greater number of facets are produced as oblique cases. 相似文献
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《测量评论》2013,45(75):227-232
AbstractThe oblique or general case of the gnomonic projection receives little serious attention in most text books on map projections and in the works which do include the theory it is unfortunately developed with unnecessary complexity. In consequence it is much less widely understood than are the special cases represented by the polar and equatorial forms. Yet the oblique form provides a gratieule which has proved incomparably more useful than either of the two Inore obvious and popular special cases. Thus, oblique cases have provided the graticules for the series of gnomonic charts of the oceans published by the Hydrographic Department of the Admiralty; the G.S.G.S. Consol Plotting Charts and the Gnomonic Fixing Chart (prepared specially for use with long range radio aids to navigation) are all oblique gnomonic graticules as are the special purpose charts for position fixing from radio bearings published by the Admiralty. In addition, all large scale port plans included in the range of Admiralty charts are drawn on a modified gnomonic. It is only in connection with the production of facets for “near globes” that one can point to the use of the polar and equatorial cases of the gnomonic and even here the greater number of facets are produced as oblique cases. 相似文献
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The adaptive composite map projection technique changes the projection to minimize distortion for the geographic area shown on a map. This article improves the transition between the Lambert azimuthal projection and the transverse equal-area cylindrical projection that are used by adaptive composite projections for portrait-format maps. Originally, a transverse Albers conic projection was suggested for transforming between these two projections, resulting in graticules that are not symmetric relative to the central meridian. We propose the alternative transverse Wagner transformation between the two projections and provide equations and parameters for the transition. The suggested technique results in a graticule that is symmetric relative to the central meridian, and a map transformation that is visually continuous with changing map scale. 相似文献
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连续多尺度表达是当前地图制图领域中的热点问题之一,常规地图采用多级瓦片剖分、多版本存储技术实现空间多尺度表达,存在数据量冗余、跨级别不一致、瓦片间尺度跳跃大等问题。结合传统地图综合、多尺度表达数据结构和空间索引建立等多种策略,在目标数据模型中加入尺度维和操作信息,记录地图综合的过程和尺度变换,建立空间数据矢量金字塔模型。该模型离线综合获取多级基态尺度表达数据,确定每个目标的尺度表达空间范围,并通过面向对象建模技术将目标表达状态及其纵向关联关系、算子类型及控制参量等信息封装在多尺度目标中;同时,建立一端或两端控制的尺度变换结构。基于该模型可快速获取适应用户需求的连续尺度表达状态。 相似文献
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地球剖分格网研究进展综述 总被引:2,自引:2,他引:0
通过梳理近十多年来地球剖分格网的相关研究文献,从剖分建模(四边形剖分、等积剖分和立体剖分)、编码计算(层次编码运算、填充曲线编码运算和整数坐标编码运算)、质量评价(评价准则、评价因子和层次传播趋势)及典型应用(政府机构应用、商业系统应用和行业领域应用)等4个方面,对该领域研究进展进行了系统的分类分析,较为详细地给出了不同格网模型的结构特点、适用模式及其存在的不足。最后总结出地球剖分格网在理论基础完备性、格网计算高效性及格网质量可靠性等方面研究的前沿问题。 相似文献