Accuracy Assessment of Google Earth and Open-source Digital Elevation Models in China Using GPS on Field Control Points.

Google Earth (GE) provides accurate and reliable global high-resolution images and can obtain the coordinates of any point on Earth's surface. A digital elevation model (DEM) is a dataset that quantitatively reflects the elevation of Earth's surface. Although GE and DEMs can be used to obtain the coordinates of any position on Earth, their open-access data can be affected by various factors, thereby inducing undesirable precision variability. Therefore, it is essential to estimate the accuracy of GE and open-source DEMs. In this study, 325 high-precision GPS survey points in 16 regions in China were used to evaluate the horizontal and vertical accuracies of GE and the elevation accuracy of two open-source DEMs. GE had a high horizontal accuracy with a root mean square error (RMSE) of 2.495 m and an error range of 1.090--4.844 m. The elevation accuracy of GE (RMSE = 2.610 m) was lower than those of TanDEM-X (RMSE = 2.055 m) and AW3D30 (RMSE = 2.373 m) DEMs. At the same time, the impacts of slope, aspect, and feature type on the accuracy of these data are studied and analyzed. The results show that the accuracy of control data are closely related to the characteristics of the study area. Overall, these findings indicate that for future studies in China, GE can be used to acquire horizontal data, whereas TanDEM-X and AW3D30 are more suitable for elevation data that have higher precision and provide a reference for relevant research on geographic information. [ABSTRACT FROM AUTHOR]