The height difference between A and B:
h h i s 1ksli2 n i s 2 1
§4-2 Stadia surveying
❖三、 The steps of the stadia surveying
1．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；
❖ 二、The stadia formula when sight is tilting Horizontal distance D :
D k' lkclo sl' lcos
D D co k scl2 os
Elementary height difference:
h D si k n cls ois netic rangefinder
一、Ectromagnetic ranging overview
2. Rangefinder classification （1）carrier wave adapted ❖ Microwave rangefinder ❖ Photoelectric rangefinder
The relative error:
K
D往D返
D
1 ＝1
1 2(D往D返)
D平
1
D平 M D
§4-1 Steel tape distance surveying
2. The distance surveying at the tilt ground ❖ (1) flat surveying method: ❖ (2) inclined surveying method
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
❖ 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）
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。
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§4-2 Stadia surveying
❖四、Stadia measurement errors
D L2 h 2
D L Dh
h2
Dh 2L
1
§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.
❖Key content:坐标方位角（ coordinates azimuth calculation ）
❖ Classification: Direct measurement method -- steel tape
distance surveying; Optical measurement method -- stadia
Endpoint rule
Compartm1entalized rule
§4-1 Steel tape distance surveying ❖ 一、The tools
❖ 2. Flower stem: Fixed line forward direction line ❖ 3. Measuring brazing: fix rule segment endpoint
ser rangefinder 2.Infrared rangefinder （2） method to calculate time ❖ Phase type rangefinder ❖ Pulsed rangefinder
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§4-3 Electromagnetic rangefinder
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§4-3 Electromagnetic rangefinder
❖二、Pulse photoelectric surveying distance
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§4-3 Electromagnetic rangefinder
三、Phase photoelectric rangefinder 1.Basic principle
distance surveying； Physical measurement method -- photoelectric
surveying distance;
§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）.
position.
❖ 二、直线定线（Fixing line）
❖ 目测定线和经纬仪定线
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§4-1 Steel tape distance surveying
❖三、 Steel tape distance surveying
❖ The basic requirements: “straight, level, accurate". ❖ 1. The distance surveying at flat ground
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§4-3 Electromagnetic rangefinder
❖一、Ectromagnetic ranging overview
1. 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.
(3) according to distance Remote –range: tens of kilometers Medium-range : from several kilometers to 10 kilometers Short-range: below three kilometers
Chap.4 Distance surveying and line orientation
Highway school Chang’an university
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:
cT c
f
t 2f
D c 4f
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§4-3 Electromagnetic rangefinder
三、Phase photoelectric rangefinder 2．Basic formula
Set modulated signal is sine signal,
including the euploid of 2π,2 N2π, and terminal partψ less than 2π, namely:
measurement ❖ 6. The influence of external meteorological
conditions to stadia measurement ❖ (1) the influence of atmospheric refraction ❖ (2) the influence of atmospheric turbulence
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）
❖ (4) by carrier number Single carrier: visible light, Infrared light, microwave. Double carrier: visible + visible light, Visible + infrared radiation Three carrier: visible + visible + microwave, Visible + infrared + microwave etc.