The Refinement Of Quasi Geoid And Comparison Of The Application Software

Farthlike surface refinement utililzes high-precision,high-resolution models to obtain elevation datum planes,and uses GPS technology to directly obtain normal heights,replacing traditional cumbersome leveling measurements,greatly reducing field work load,reducing production costs,and shortening the cycle of obtaining measurement results..Therefore,the refinemcen of the geoid is one of the important tasks for a country or region to establish a modern elevation benchmark.In the past few decades,several generations of surveyors in China have used I:10 million or smaller scale topographic maps to conduct surveys and control points before data collection.However,it is limited to the economic level of our country.Until 2011,there are still a large number of map blank areas.At present,small-scale topographic maps cover the whole country.Based on this,it is possible to conduce geodetic surveys of field selections and huried stones.However,the topographic map is the basic surveying and mapping data of China.In the storage of confidentiality and data collection,the external surveying and mapping requires safely production operations.At the same time,the correct combination of features and topography to determine topographic map orientation has a higher requirement for the basic quality of workers.The anomalously anomalous spherical grid values.calculated using the advanced Earth Gravity Field model are visualized.Thc use of unique isoline rendering software is the key.The ability to draw regional elevation anomalies using currently mature commercial software is something that all geodetic researchers have been studying in recent years.Based on the above research status,the author has studied and discussed the map-based geospatial surface refinement process of Maplnfo software supporting urban road map design.The selected map can completely replace traditional small-scale topographic maps for field construction.Compared with the traditional process,it has the following three Advantages:(l)All points are displayed on the same platform,and the spacing between points can be calculated through the software measurement tool.The operator's requirements are simple and the threshold is low.And the designed point number can be continuously incremented according to the latitude and longitude relationship.Reduced the requirements of internal designers;(2)The road traffic map allocated is completely free.Through road traffic information,it can flexibly provide accurate traffic routes for field operators,saving time and effort.And the road traffic map is more field usable than the original topographic map.It will not cause major security risks in the disclosure of information;(3)The point point designed on the computer desktop has a CGCS2000 national Geodetic coordinate system,which can reach a range of several tens of meters or even meters from the design point through a handheld or Ovey map.The requirements for distinguishing features and landforms from topographic maps are reduced.Through the drawing of the elevation anomaly contour of a city,we can see that:Global mapper software mapping process is cumbersome,Surfer software can not objectively and correctly reflect the trend of elevation anomaly contour,and GMT software can correctly express elevation anomalies in the area.Trend.In this paper,based on the research status of geoid-level surface refinement at home and abroad,the current domestic geoid refinement method is studied,combined with the application of MapInfo software in the process of geostatistical refinement data collection in a city.After the abnormally high grid values,the GMT software was used to intuitively display the regional contour anomaly contour maps;finally,the applicability of each software and other methods to achieve the geoid design and results analysis stage was compared in detail.Through the study of the thesis,it is concluded that Maplnfo professional and GMT software can solve the technical design and elevation anomaly contour contour mapping in geoid-like surface refinement process,and obtain some beneficial conclusions.The broad prospects of geoid refinement.