An illustrative example method of mapping a physical environment using an occupancy grid containing a set of cells associated with respective occupancy probabilities includes measuring a potential position of an object, using a sensor and identifying a segment representing a distribution interval of probable values associated with respective probability values relating to the measured potential position. The segment extends according to only one of two dimensions of the coordinate system of the sensor and penetrates a subset of potentially occupied cells. The method includes evaluating a probability of occupancy of each potentially occupied cell by determining the features of a segment portion included in the potentially occupied cell, and determining the probability of occupancy of the potentially occupied cell as a function of the determined segment portion using the probability density function.