玲珑山及其周边地区SRTM3和ASTER GDEM高程精度评价

Accuracy Assessment on Elevation of Linglong Mountain and Its Surrounding Areas Simulated by SRTM3 and ASTER GDEM Models

为研究林业应用中小区域范围内数字高程模型(DEM)的高程精度,以地势起伏明显的玲珑山及其周边地区为试验区,利用中误差、等高线套合积差2种定量指标评价方法和DEM回放等高线目视检验主观评价方法对SRTM3和ASTER GDEM 2种免费数字高程模型进行高程精度分析。结果表明:森林覆盖对DEM的精度存在一定的影响,试验区内SRTM3的中误差和等高线套合积差为11.534 m和0.177,ASTER GDEM的中误差和等高线套合积差为10.459 m和0.166,均达到官方公布的精度,且ASTER GDEM精度略高于SRTM3;从DEM回放等高线目视检验来看,2种数据提取的等高线对试验区山地描述比较符合实际情况,但对试验区河谷平原处地形描述较差,其中SRTM3提取的等高线偏移较大。综合考虑,玲珑山及其周边地区优先推荐使用ASTER GDEM数据。

Choosing Linglong Mountain with varied relief and its surrounding areas as the experimental zone, the accuracy of elevation simulated by two types of free digital elevation model （DEM）including Shuttle Radar To-pography Mission 3 （SRTM3）and the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model （ASTER GDEM）was analyzed by means of applying two quantitative evaluation methods, namely the root mean square errors （RMSE）and the accumulation products （AP）,and one subjective evaluation method,i.e.visual inspection of reconstructing contours through DEMto testify the application of DEMto small re-gions in forestry sector.The results showed that forest cover in the experimental zone had some influence on eleva-tion accuracy simulated by DEM,the value of RMSE and AP by SRTM3 was 1 1.534 m and 0.177,whereas the value of RMSE and AP by ASTER GDEMwas 10.459 m and 0.166,respectively.Though the accuracy of elevation simulated by both SRTM3 and ASTER GDEM in the study area met the demand published officially,the elevation accuracy of ASTER GDEM was higher than that of SRTM3.The results from the visual inspection of reconstructing contours through DEM suggested that the contours extracted by SRTM3 and ASTER could better describe the practi-cal status of the low mountainous terrain in the experimental area,but the interpretation for the river valley or plain area was not so precise,and the deflection of contours derived from SRTM3 was a bit larger than that of derived from ASTER GDEM.Comprehensively concluding that the data from ASTER GDEM were preferably recommended apply to Linglong Mountain and its surrounding areas to simulate the elevation contour.