Accuracy assessment of Openly Accessible CartoDEM V3R1 and TanDEM-X 90 using Smartphone having Assisted GPS for Ratlam City and Surroundings

Digital Elevation Model (DEM) is mostly used to extract the terrain parameters for surface and elevation analysis for representing the topography of earth surface in the best possible way. Nowadays smart devices such as smartphones, tablets employed with GPS chipsets are easily available in the market and can be used for positioning and navigation. These smart devices can measure elevation data and are cost-effective. The plain areas of Ratlam City (Madhya Pradesh) was the study area. Vivo 1606 smartphone incorporated with Assisted-GPS is used with GPS utility App called Mobile Topographer to collect the ground coordinates and elevation data. The ground control points (GCPs) were collected in parts of urban areas, such as open grounds, streets, parks, and other uniformly distributed GCP locations. Using smartphone derived GCPs as a reference the two openly accessible DEMs namely, CartoDEM V3 R1 (30m) and TanDEM-X (90m) were evaluated statistically. Statistical parameters such as Mean Error (ME), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE) were computed for comparative quality analysis between CartoDEM V3 R1, and TanDEM-X 90m, using the observed GPS elevation data. The ME (4.60 m), MAE (6.12 m), and RMSE (7.15 m) for TanDEM-X were higher than that of CartoDEM V3 R1, ME (3.09 m), MAE(50.5 m), and RMSE (6.17 m) respectively. The results revealed that the accuracy of CartoDEM V3 R1 is higher and it statistically performs better than TanDEM-X 90m in plain areas of Ratlam.