The quality of elevation data plays a pivotal role in various land transport activities, such as accessibility analyses, route optimization, and estimates of energy demand and gas emissions. This study evaluates the accuracy of altimetric profiles obtained during a car trip. The compared methods include (1) barometric altimetry using a low-cost pressure module; (2) single-point satellite positioning using a low-cost receiver; (3) postprocessed relative kinematic (PPK) satellite positioning using a geodetic receiver; (4) the Shuttle Radar Topography Mission digital elevation model (DEM); and (5) the digital terrain model provided by the GeoSampa portal for São Paulo City, used as the reference dataset. Moreover, the paper explores corrections for barometric altimetry to address the well-known issues of systematic errors and high-frequency noise in low-cost modules. A high correlation among the altimetric profiles was identified, but a notably higher accuracy was observed in the profiles and road grades obtained by PPK satellite positioning and barometric altimetry after the correction for systematic errors and filtering through moving average for noise reduction. The results highlight the importance of a careful choice of altimetric bases and processing techniques to prevent inaccuracies in road projects and analytical models.
Oliveira et al. (2026) studied this question.