04. Accuracy assessment of elevation derived from Google Earth data based on static GPS/GNSS measurement: a case study in Ha Giang province, Vietnam

Abstract

This study aims to compare elevation data derived from Google Earth (GE) with the elevation measured by static Global Positioning System (GPS)/Global Navigation Satellite System (GNSS) at 68 control points in ​​Vinh Tuy town, Bac Quang district, Ha Giang province. The results showed that elevation data extracted from GE has a large deviation from data measured by static GPS/GNSS. Mean absolute error, root-mean-square error and standard deviation of 68 points were 2.254 m, 4.991 m and 4.486 m respectively. Some study points were inaccuracy up to more than 10 m, such as: VT01 (10.529 m), VT16 (11.576 m), VT26 (14.564 m), VT47 (14.317 m) and VT60 (14.794 m). The findings of this study confirm that GE elevation data is not suitable for engineering projects, such as leveling works (<0.67 m), building 3D maps (<0.83 m), modelling and building flood maps at medium scale (<10.0 m),…in mountainous areas as Ha Giang province, Vietnam.