wgs84

Overview for converting local plane coordinates to WGS84

南楼画角 提交于 2021-02-10 05:30:42
问题 Let's say I have a small area mapped out using local planar coordinates in meters. e.g. A rectangular warehouse that's 300m x 450m. I use some GPS device to find the WGS 84 lat/lon of one corner of the warehouse. How can I project my plane coordinates onto the WGS 84 geoid to find the lat/lon values for the 3 other corners of the warehouse? I understand this is a complicated problem since values vary on different parts of the earth. Do I need to deal with finding some local coordinate system

Overview for converting local plane coordinates to WGS84

萝らか妹 提交于 2021-02-10 05:30:29
问题 Let's say I have a small area mapped out using local planar coordinates in meters. e.g. A rectangular warehouse that's 300m x 450m. I use some GPS device to find the WGS 84 lat/lon of one corner of the warehouse. How can I project my plane coordinates onto the WGS 84 geoid to find the lat/lon values for the 3 other corners of the warehouse? I understand this is a complicated problem since values vary on different parts of the earth. Do I need to deal with finding some local coordinate system

通过PROJ4转换地理数据到GoogleMap投影坐标系

删除回忆录丶 提交于 2020-03-15 02:27:55
Google Map以及VirtualEarth等web gis都采用一种特殊的投影坐标系EPSG:900913,其实这个900913并不是EPSG分配的编号,而是设计Google Map的工程师自己选定的一个编号。该投影坐标系一开始不被EPSG组织承认(EPSG认为这个坐标系的参数设定非常不符合地理科学),后来因为使用的人越来越多,不得已承认了,但分配了一个别的编号epsg:3785而不是900913。但是大多数程序员不知道,还一直使用900913,呵呵。 关于epsg:3785投影坐标系的详细参数如下:(参考 http://spatialreference.org/ref/epsg/3785/ ) +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs 上面这组参数是用于PROJ4(一个著名的地理投影变换开源库)的,我用以上参数以及从中国国家测绘局下载的中国地图数据和Google Map对照了一下发现x坐标(经度)没有差异,但是y坐标有较大的差异。后来在下述网页 http://proj.maptools.org/faq.html 的最后一个问题上发现需要一个额外的参数: The coordinate system

Place an HTML element on a Cesium Entity's position

怎甘沉沦 提交于 2020-01-30 08:20:48
问题 I need to define the location of an html element based on the location of a Cesium entity. I've used the mouse position ( Cesium.Cartesian3.clone(movement.endPosition) ), which is in window coordinates, as a test and it works. So I need to get the entity position, transform it to the WGS84 coordinates, transform those to the window coordinates and use them for element.style.left = window_coord.x and element.style.top = window_coord.y . So I get the entity.position and the x, y and z values

OpenLayers after call setCenter, map is still on 0,0 position

∥☆過路亽.° 提交于 2020-01-05 08:42:36
问题 I tried to set map center by method setCenter, but still not working. Map is not moving. I tried to used transform from projection to map projection and without successful. Here is part of code. Thanks. <script type="text/javascript"> var lon = 15.869378; //WGS LL84 var lat = 49.528964; var zoom = 5; var map, layer; function init(){ map = new OpenLayers.Map('map'); layer = new OpenLayers.Layer.TMS("Name", "[URL]", { 'type':'png', 'getURL':get_my_url }); map.addLayer(layer); var markers = new

OpenLayers after call setCenter, map is still on 0,0 position

强颜欢笑 提交于 2020-01-05 08:42:14
问题 I tried to set map center by method setCenter, but still not working. Map is not moving. I tried to used transform from projection to map projection and without successful. Here is part of code. Thanks. <script type="text/javascript"> var lon = 15.869378; //WGS LL84 var lat = 49.528964; var zoom = 5; var map, layer; function init(){ map = new OpenLayers.Map('map'); layer = new OpenLayers.Layer.TMS("Name", "[URL]", { 'type':'png', 'getURL':get_my_url }); map.addLayer(layer); var markers = new

Accurate parallel swathing algorithm for (GPS) guidance needed

久未见 提交于 2019-12-24 01:58:09
问题 I wrote a delphi program generating a gpx file as input for a "poor man's guidance system" for aerial spray by means of ultralight plane. By and large, it produces route (parallel swaths) using gpx file as output. The route's engine is based on the "Vincenty" algorithm which works fine for any wgs84 computation but I can't get the accuracy of grid generated by ExpertGPS of Topografix (requirement). I assume a 2D computation on the ellipsoïd : 1) From the start rtept (route point), compute the

聊聊GIS中的坐标系|再版

我们两清 提交于 2019-12-23 06:03:14
本文约6500字,建议阅读时间15分钟。 作者:博客园/B站/知乎/csdn/小专栏 @秋意正寒 版权:转载请告知,并在转载文上附上转载声明与原文链接( https://www.cnblogs.com/onsummer/p/12081889.html )。 【目录】 1. 经纬度与米【告诉大家GIS中的坐标系核心的两种坐标系定义,地理坐标系统vs投影坐标系统】 2. 为什么有两种表达(不同点) 3. 内在联系(相同点)【指出投影坐标系统的广义定义,即PCS=f(GCS)】 4. 常用坐标系统(4.1 WKID;4.2 地理坐标系统;4.3 投影方法;4.4 投影坐标系统;4.5 GCJ02与BD09;4.6 经纬度直投) 5. 常用坐标系统的判别与常用软件中的操作(待补充) 我的牢骚与参考文档 1. 经纬度 (例: 119.32°E, 32.48°N)与 米 (∟, 直角坐标) 让基础浅薄的同学、GIS外行疑惑的,可能就是这两种“单位”的坐标值,以及他们的转换了吧。 2019年是一个不同寻常的年份,大大小小的地震总能被人民日报大V转发。 地震信息一般会带什么呢? 这是一条地震消息,它除了时间、地震等级等消息外,有一个很重要的消息:北纬36.16度,东经98.93度,为了方便,我们用数学的坐标表示法: 点P,P(98.93°E, 36.16°N) 其中,E就是单词East(东)

How to convert GPS coordinates to decimal in Lua?

空扰寡人 提交于 2019-12-20 04:57:16
问题 I need to convert GPS coordinates from WGS84 to decimal using Lua. I am sure it's been done before, so I am looking for a hint to a code snippet. corrected question: Code to convert DMS (Degress Minutes Seconds) to DEG ((decimal) Degrees) in Lua? examples: Vienna: dms: 48°12'30" N 16°22'28" E or Zurich: dms: 47°21'7" N 8°30'37" E The difficulty I find is to get the numbers out of these strings. Especially how to handle the signs for degree (°) minutes (') and seconds ("). So that I would have

地球坐标系与投影方式的理解(关于北京54,西安80,WGS84;高斯,兰勃特,墨卡托投影)

≡放荡痞女 提交于 2019-12-18 14:58:17
一、地球模型 地球是一个近似椭球体,测绘时用椭球模型逼近,这个模型叫做 参考椭球 ,如下图: 赤道是一个半径为a的近似圆,任一圈经线是一个半径为b的近似圆。a称为椭球的长轴半径,b称为椭球的短轴半径。 a ≈ 6378.137千米,b≈6356.752千米。(实际上,a也不是恒定的,最长处和最短处相差72米,b的最长处和最短处相差42米,算很小了) 地球参考椭球基本参数: 长轴:a 短轴:b 扁率:α=(a-b) / a 第一偏心率:e=√(a 2 -b 2 ) / a 第二偏心率:e ' =√(a 2 -b 2 ) / b 这几个参数定了,参考椭球的数学模型就定了。 什么是大地坐标系? 大地坐标系 是大地测量中以 参考椭球 面 为基准面建立起来的坐标系。地面点的位置用大地经度、大地纬度和大地高度表示:(L, B, H)。 空间直角坐标系 是以 参考椭球 中心 为原点,以原点到0度经线与赤道交点的射线为x轴,原点到90度经线与赤道交点的射线为y轴,以地球旋转轴向北为z轴:(x, y, z) 共同点:显然,这两种坐标系都必须基于一个参考椭球。 不同点:大地坐标系以面为基准,所以还需要确定一个标准海平面。而空间直角坐标系则以一个点为基准,所以还需要确定一个中心点。 只要确定了椭球基本参数,则大地坐标系和空间直角坐标系就相对确定了,只是两种不同的表达而矣,这两个坐标系的点是一一对应的。