高等级公路测量基准面的确定及长度变形分析

Determination of Datum Surface of Horizontal Control Net and Analysis of Length Projection Deformation for High-grade Highway Surveying

分析了高等级公路平面控制网导线边投影长度变形与测区平均高程及投影带宽度的关系．根据长度变形是否满足国家标准GB50026－93要求（≤2．5cm／1km）而确定坐标系统．给出了不同坐标系统之间的换算关系．文中算例表明：用简单算法能达到公路工程测量的精度要求．

The relations between the length projection deformation of a horizontal control net and the mean altitude and width of a projection belt in the high-grade highway surveying have been analysed. According to the Allowance of National Criterion GB 50026-93about the length projection deformation (≤2. 5 cm/1 km), author of this paper selects aproper coordinate system and presents a transformable calculation Way among different coordinate systems. The calculating example in this paper proves that the single calculatingway proposed by the auther is a practical one and can meet the accuracy requirements ofthe National Griterion GB 50026-93.