Summary: | 碩士 === 國立宜蘭大學 === 土木工程學系碩士班 === 106 === Most of Surveying and Mapping industry uses Network RTK to measure the facilities, manhole covers and handhole covers directly. It’s measured the three-dimensional coordinates of the measured points immediately. But elevation value is Ellipsoid Height. It’s still necessary to measure the points of the three-dimensional coordinates and then through Geoid Undulation Model of Taiwan is converted to Orthometric Height. But the current Surveying and Mapping industry or related academic units can only be completed by Ministry of the Interior and National Land Surveying and Mapping Center’s Geoid Undulation Model of Taiwan on 2014 to convert. Before the plan is completed, The Ministry of the Interior in 2002 was first published Geoid Undulation Model of Taiwan. In part of areas, is the Geoid Undulation Model of Taiwan on 2014’s converted result better than Geoid Undulation Model of Taiwan on 2002’s converted result?It's explored the subject for this thesis.
In this study, the two experimental areas in Hukou Township, Hsinchu County, and Xincheng Township, Hualien City, Ji’an Township, Shoufeng Township, Fenglin Township, Hualien County, respectively. They were tested the real data. And then the experimental area in the island of Taiwan within range, in accordance with point data using the longitude and latitude of each read gap 30 seconds to build unreal data, and the 2002 edition and the 2014 edition including hybrid and gravity method of the Geoid Undulation Model of Taiwan calculation formula calculates, analysis and calculation of three editions of the program differences.
The real data experimental results show, in terms of the experimental area in Hukou Township, Hsinchu County,the difference between 2014 edition including hybrid method of the Geoid Undulation Model of Taiwan and 2002 edition is small, and it still had their own applicable regional location.Hybrid and gravity method’s systematic offset value is between 13 and 17cm. In terms of the experimental area in Hualien County. According to the relevant operational specifications developed by Construction and Planning Agency Ministry of the Interior. Hybrid method’s pass rate is up to 95%, but the 2002 edition’s pass rate is only 67%. And 2014 edition including hybrid method of the Geoid Undulation Model of Taiwan is indeed better than 2002 edition. Hybrid and gravity method’s systematic offset value is between 19 and 26cm.The grid data experimental results show, the precision in the flat area is better than that in the mountain area. In the range of Taiwan island, the differences between 2014 edition including hybrid method and gravity method of the Geoid Undulation Model of Taiwan are the most in the range of 10cm to 30cm, accounting for 90%. In the full range of Taiwan, this is also mentioned previously between the two methods' systematic offset value.
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