长安大学测量学双语PPT 第4章

长安大学测量学双语PPT

Chap.4 Distance surveying and line

orientation

Highway school Chang’an university

长安大学测量学双语PPT

Chap.4 Distance surveying and line orientation Distance: refers to length of the curve line between two projections of two points to the geoid along the plumb line. Main contents: 钢尺量距(steel tape distance surveying ); 视距测量(stadia surveying ); 光电测距(photoelectric surveying distance) 卫星测距(Satellite ranging); 直线定向(line orientation);1

长安大学测量学双语PPT

Key content:坐标方位角( coordinates azimuth calculation ) Classification: Direct measurement method -- steel tape distance surveying; Optical measurement method -- stadia distance surveying; Physical measurement method -- photoelectric surveying distance;

长安大学测量学双语PPT

§4-1 Steel tape distance surveying 一、The tools钢尺(Steel tape), 标杆(benchmarking), 测钎 (measuring brazing) and 垂球(Metal ball ball). 1. Steel tape Feet long : 20 meters, 30 meters, 50 meters ; Specifications: plastic coated or not plastic coated. Scale and note: mm, cm, dm,m 刻线尺(compartmentalized rule) 端点尺(endpoint rule)

Endpoint rule

Compartmentalized rule 1

长安大学测量学双语PPT

§4-1 Steel tape distance surveying 一、The tools 2. Flower stem: Fixed line forward direction line 3. Measuring brazing: fix rule segment endpoint position.

二、直线定线(Fixing line) 目测定线和经纬仪定线

1

长安大学测量学双语PPT

§4-1 Steel tape distance surveying 三、 Steel tape distance surveying The basic requirements: “straight, level, accurate". 1. The distance surveying at flat ground Use the equation: D=nl+q l - the the length of whole feet; n - the whole rule section number, q - zero rule section length. surveying error: D = D往-D返 Distance average: D平= ½ (D往-D返)The relative error:

K

D往 D返 1 ( D往 D 返 ) 2

D D平1

1 1 = D平 M D

长安大学测量学双语PPT

§4-1 Steel tape distance surveying2. The distance surveying at the tilt ground (1) flat surveying method: (2) inclined surveying method

D L2 h 2 D L Dh h2 Dh 2L1

长安大学测量学双语PPT

§4-2

Stadia surveying

Stadia surveying is indirect ranging method 它利用望远镜内十字丝分划板上的视距丝及刻有厘米分 划的视距标尺(地形塔尺或普通水准尺),根据光学原理可以 同时测定两点间的水平距离和高差.

The relative error is about 1/300, below the rule surveying distance, Determine the elevation precision is below level survey, Stadia measurement is widely used for measuring the details topography Measurement.1

长安大学测量学双语PPT

§4-2

Stadia surveying

一、Stadia formula when sight is horizontal

n

D D f 1

D n f1 p

f 1 ( f 2 b) D n f2 p

f1 ( f 2 b ) bf1 D n n f1 f2 p f2 p 1

D Kn c

长安大学测量学双语PPT

§4-2

Stadia surveying

一、Stadia formula when sight is horizontal

n

Ho

rizontal distance formula: D Kn c 100n Height difference formula: hAB i l1

l

长安大学测量学双语PPT

§4-2

Stadia surveying

二、The stadia formula when sight is tilting Horizontal distance D :

D kl ' kl cos l ' l cos

D D cos kl cos2 Elementary height difference:

h D sin kl cos sin The height difference between A and B:

1 h h i s kl sin 2 i s 21

长安大学测量学双语PPT

§4-2

Stadia surveying

三、 The steps of the stadia surveying1.在测站上安置经纬仪，量取仪器高(桩顶至仪器横轴中心 的距离),精确到cm; 2.瞄准竖直于测点上的标尺，并读取中丝读数值； 3.用上、下视距丝在标尺上读数，将两数相减得视距间隔； 4.使竖盘水准管气泡居中，读取竖盘读数，求出竖直角; 5.根据视距公式，计算水平距离和高差及立尺点的高程。

1

长安大学测量学双语PPT

§4-2

Stadia surveying

四、Stadia measurement errors 1. The stadia rule partition error 2. Constant K value error 3. Vertical Angle measurement errors 4. Stadia cross reading error 5. Influence of stadia rule tilting to stadia measurement 6. The influence of external meteorological conditions to stadia measurement (1) the influence of atmospheric refraction (2) the influence of atmospheric turbulence1

长安大学测量学双语PPT

§4-3 Electromagnetic rangefinder 一、Ectromagnetic ranging overview1. Principle To record the electromagnetic wave traveling time between two endpoints round-trip once time, using its propagation velocity in the atmosphere to calculate the distance between two points.

1

长安大学测量学双语PPT

§4-3 Electromagnetic rangefinder一、Ectromagnetic ranging overview2. Rangefinder classification (1)carrier wave adapted Microwave rangefinder Photoelectric rangefinder http://www.77cn.com.cnser rangefinder 2.Infrared rangefinder (2) method to calculate time Phase type rangefinder Pulsed rangefinder1

长安大学测量学双语PPT

§4-3 Electromagnetic rangefinder(3) according to distance Remote –range: tens of kilometers Medium-range : from several kilometers to 10 kilometers Short-range: below three kilometers (4) by carrier number Single carrier: visible light, Infrared light, microwave. Double carrier: visible + …… 此处隐藏：2451字，全部文档内容请下载后查看。喜欢就下载吧 ……