Horizontal positional accuracy of Google Earth's imagery over rural areas: a study case in Tamaulipas, Mexico

Abstract

Due to the popularity of Google Earth (GE), users commonly assume that it is a credible and accurate source of information. Consequently, GE's imagery is frequently used in scientific and others projects. However, Google states that data available in their geographic products are only approximations and, therefore, their accuracy is not officially documented. In this paper, the horizontal positional accuracy of GE's imagery is assessed by means of comparing coordinates extracted from a rural cadastral database against coordinates extracted from well-defined and inferred check points in GE's imagery. The results suggest that if a large number of well-defined points are extracted from areas of high resolution imagery, GE's imagery over rural areas meets the horizontal accuracy requirements of the ASPRS for the production of "Class 1" 1:20,000 maps. Nonetheless, the results also show that georegistration and large horizontal errors occur in GE's imagery. Consequently, despite its overall horizontal positional accuracy, coordinates extracted from GE's imagery should be used with caution.

Horizontal accuracy assessment of very high resolution Google Earth images in the city of Rome, Italy

“…For instance, at a global scale Potere (2008) horizontal accuracy in 6.1 m RMSE r , by using CPs extracted from 1:2000 scale maps of three towns of the study area in Iran. In another major study, Paredes-Hernandez et al (2013) have recently reported an accuracy of 5.0 m RMSE r , by using CPs located over a rural area and extracted from a cadastral database. As expected, the results obtained in this study also gave different accuracies for the two different sets of CPs and suggest that the horizontal accuracy estimated using inferred GPS points is higher than the accuracy estimated using only PF points (Tables 1-2).…”

“…The first systematic study on positional accuracy was reported by Potere (2008), who determined the absolute accuracy of GE images at a global scale for several worldwide places. In another study, Paredes-Hernandez et al (2013) undertook the accuracy assessment at a regional scale over rural areas in Mexico. Similarly, in a study about direct orthorectification of raw satellite images, Yousefzadeh and Mojaradi (2012) validated the accuracy of GE images in two test sites before using them to extract planimetric ground control and check points (CPs).…”

A Computer Vision Line-Tracking Algorithm for Automatic UAV Photovoltaic Plants Monitoring Applications

“…Note that georeferenced maps obtained from satellite imagery, e.g., Google Earth, widely used in this framework, are not a complete reliable source of information. Researches in the literature have shown that the error in planimetric coordinates (North, East), between objects as captured in Google Earth and obtained from a base map produced by ground surveying techniques, ranges from 5 [22] to 10 m [23] and even more [24,25], depending, among many factors, on the geographic location. The accuracy of measured distances in Google Earth is considerably better than the accuracy of measured individual coordinates, but, in any case, an error of 2 or more meters can be expected [26].…”

Assessment of Mining Extent and Expansion in Myanmar Based on Freely-Available Satellite Imagery

“…Post-monsoon 2002 images from Landsat 5 or 7 and 2015 images from Landsat 8 were used for the comparison. Landsat sensors are well calibrated, facilitating monitoring over time, and the horizontal position accuracy is on par with the position accuracy expected from the imagery available on Google Earth [42]. Consideration was given to applying multispectral and panchromatic image fusion methods to combine the Landsat ETM+ and OLI 15 m panchromatic and 30 m multispectral image bands, however we decided against this approach since the Thematic Mapping instrument on-board Landsat 5 did not have a panchromatic band and our work flow relied on using reflectance values which cannot be preserved when performing image fusion.…”