用航测技术测绘数字化工点地形图和横断面图的研究

利用航测技术测绘大比例尺工点图和横断面图，是铁路勘测设计部门重点研究的关键技术问题之一，其主要难点在于采用小比例尺航摄，精度达不到要求；采用大比例尺航摄，航摄费用过高。本文作者利用GPS全球定位技术使航测外业控测精度由分米级达到厘米级；航测内业采用数字摄影测量工作站，全面开展数字测图，精度得到了提高。在理论分析和精度估算后，选定合适的航摄比例尺，采用一些技术措施，结合郑西客运专线勘测设计试验证明，用航测方法测绘工点地形图和横断面图的精度满足铁路勘测设计的要求，并总结出一套作业方法和要求。数字化产品也为设计阶段进行计算机辅助设计创造了条件。

Investigation on Digital Topographic Mapping of Construction Sites and Cross-sections Using Aerophotogrammetric Technology

Large-scale topographic mapping of construction sites and cross-sections by the aerophotogrammetry is the key technique in railway survey and design which has been long attended to and researched with great emphasis.The main difficulty is that the accuracy can not meet the practical requirement if small-scale aerial photography is adopted whereas the cost may be excessively high if large-scale aerial photography is adopted.This paper aims at the advancements of mapping technology in the recent decade.The accuracy of aerial surveying has been upgraded from sub-meter level to centimeter with the help of GPS.The photogrammetric mapping can be done by the computer workstation and the accuracy can be greatly improved.With theoretical analysis and accuracy estimation,this paper presents the operational methods and the technological requirements.By selecting the proper scale and taking some special technique the reliable topographic mapping can be achieved.Survey and design of the Zhengzhou-Xi'an Passenger Dedicated Line are used to test the method.In addition,digital products can also create conditions for CAD in the railway design stage.