成都市域的测绘系统采用独立的坐标系和高程系。而地下管线作为数字成都项目的一项基础地理信息，需要将其高程基准统一为1985国家高程基准。由于5·12汶川地震对成都平原的高程产生了一定的影响，因而在震后地下管线高程转换之前，应首先计算出汶川地震所引起的成都高程变化，并分析其对管线高程转换的影响。通过震后的二等水准网复测，并联测国家一等水准点，分析得出了地下管线高程转换方案。%The surveying and mapping of Chengdu is based on the lonely coordinates and heights .As a basic geo-matics,the height of pipes underground is needed to transformed to 1985 national height datum .5· 12 Wenchuan disas-ter do influence Chengdu height ,so it’s to calculate the height deformation with the earthquake and analyz the influence on height transformation before this work .Through the second level survey after earthquake ,the pipe height transformation method is calculated .
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