工程独立坐标系的建立
摘要：在工程建设地区布设测量控制网时，其成果不仅要满足大比例尺地形图测图的需要，还要满足一般工程放样的需要。施工放样时要求控制网中两点的实测长度与由坐标反算的长度应尽可能相符，而采用国家坐标系其坐标成果大多数情况下是无法满足这些要求的。本文主要阐述了工程独立坐标系的建立方法，通过在乾县和靖边供水工程可研阶段测量中的应用，得出了一些有益的结论和建议。
关键词：国家坐标系，独立坐标系，中央子午线，抵偿高程面
Abstract: in the engineering construction area layout measure control network, its results not only meets the large scale topographic map surveying the need, but also meet the needs of the general projects layout. When construction lofting requirements in the two control net by the length and the length of the coordinates should as far as possible and is consistent with national coordinate system and the coordinate results in most cases is unable to meet these requirements. This paper mainly expounds the methods to set up the independent coordinate system engineering, through in situations water supply project of qian county and feasibility study stage of the application of the measurement and draw some useful conclusions and Suggestions.
Keywords: national coordinate system, independent coordinate system, the central meridian, counter elevation face
1. 独立坐标系的建立方法
1.1抵偿高程面法
在国家高斯坐标系中，其投影面为参考椭球面；而一般在工程控制网中，高程基准面往往不是参考椭球面，而是与参考椭球面不重合的测区平均高程面。从而导致以国家高斯坐标系中的坐标反算出来的距离与实际地面的长度不相等。
1.2任意投影带法
把中央子午线移到测区中央，建立任意带高斯正形投影平面直角坐标系，这样可以使测区的两项改正在测区中央几乎为零。
1.3抵偿高程面+任意投影带法
选择平均高程面作投影面，通过测区中心的子午线作为中央子午线，按高斯
工程独立坐标系的建立
摘要：在工程建设地区布设测量控制网时，其成果不仅要满足大比例尺地形图测图的需要，还要满足一般工程放样的需要。施工放样时要求控制网中两点的实测长度与由坐标反算的长度应尽可能相符，而采用国家坐标系其坐标成果大多数情况下是无法满足这些要求的。本文主要阐述了工程独立坐标系的建立方法，通过在乾县和靖边供水工程可研阶段测量中的应用，得出了一些有益的结论和建议。
关键词：国家坐标系，独立坐标系，中央子午线，抵偿高程面
Abstract: in the engineering construction area layout measure control network, its results not only meets the large scale topographic map surveying the need, but also meet the needs of the general projects layout. When construction lofting requirements in the two control net by the length and the length of the coordinates should as far as possible and is consistent with national coordinate system and the coordinate results in most cases is unable to meet these requirements. This paper mainly expounds the methods to set up the independent coordinate system engineering, through in situations water supply project of qian county and feasibility study stage of the application of the measurement and draw some useful conclusions and Suggestions.
Keywords: national coordinate system, independent coordinate system, the central meridian, counter elevation face
1. 独立坐标系的建立方法
1.1抵偿高程面法
在国家高斯坐标系中，其投影面为参考椭球面；而一般在工程控制网中，高程基准面往往不是参考椭球面，而是与参考椭球面不重合的测区平均高程面。从而导致以国家高斯坐标系中的坐标反算出来的距离与实际地面的长度不相等。
1.2任意投影带法
把中央子午线移到测区中央，建立任意带高斯正形投影平面直角坐标系，这样可以使测区的两项改正在测区中央几乎为零。
1.3抵偿高程面+任意投影带法
选择平均高程面作投影面，通过测区中心的子午线作为中央子午线，按高斯