Research On SRTM Void-filling And Precision Detection Of SRTM Data In China

The DEM data is one of the indispensable auxiliary data in the field of geo-information emergency protection.The quality and coverage of DEM data have important significance for actual production.In the actual production,the 1:50000DEM data of the National Basic Geographic Information Center has high precision and adequate quality.However,due to the confidentiality of the data,it is impossible to directly disclose work results to the outside world in practical applications,which is not conducive to the development of emergency security.The SRTM DEM data is specific DEM data which processed by the "Space Shuttle Radar Topography" project co-hosted and conducted by NASA and the National Mapping Agency(NIMA),and covering over 80% of the global terrestrial range.Since 2015,30 m SRTM data has been opened and downloaded,which is the currently available for free DEM data with highest resolution and widest available.It is widely used in the field of geographic information emergency support.However,when the radar acquires data,it is disturbed by the specular reflection or the signal.The resulting DEM data has some void data,which is mainly concentrated in lakes,river systems,and high mountain valleys.These voids affect the accuracy evaluation and practical application of the SRTM data.Therefore,research on SRTM void-filling and precision detection of SRTM data has important partical significance.In order to fill the void data of SRTM DEM data,this paper makes a comparative study on the methods of void holes filling and interpolation at home and abroad,analyzes the principles of each interpolation method,and compares the advantages and disadvantages of various methods,five research areas with different geomorphological features were selected.First,non-void SRTM data were simulated using different interpolation methods to fill in the experiments.To verify the effectiveness of the void filling method,the interpolation results are compared with the actual values,and the average elevation error and the elevation error as the evaluation basis,then the optimal hole filling interpolation method is obtained,and then applied to the SRTM data hole for filling.The SRTM DEM data with no data holes filled will be evaluated for accuracy.In this paper,we first introduced the current mainstream DEM data accuracy evaluation methods,and the SRTM data accuracy evaluation research results of other domestic scholars in different regions as a reference.The experiment uses the 1:50000 DEMdata of the National Basic Geographic Information Center as the assumed true value and the ASTER DEM as the reference data.By using the DEM precision evaluation method,the accuracy and quality of SRTM DEM data are quantitatively analyzed in 5research areas with different geomorphologic characteristics,and the accuracy evaluation results of SRTM DEM data are finally obtained.The research results show that the SRTM DEM data hole filling based on the mobile surface fitting interpolation method enhances the data integrity and practicality.SRTM DEM has a wide coverage area and high precision in the Chinese region.In the same resolution,the data is closer to the real surface than ASTER DEM,and can meet the general use requirements in the field of geographic information.The research in this paper provides guidance and reference for the selection of DEM data in geoscience.