1. A method of extracting street and road data from a dataset obtained using LIDAR techniques to scan a terrestrial region of the earth's surface of interest to form said dataset, the method comprising the steps of: converting said dataset into an implicit representation using a population function; flattening the implicit representation into a 2D image; converting the 2D image into 2D point data which are supplied to an agglomerative Gaussian mixture decomposition module, the agglomerative Gaussian mixture decomposition module automatically and parsimoniously fitting the 2D point data with a set of Gaussian components; and modeling a segment of a street grid in the dataset by Gaussian models and constraining the Gaussian models to align with each other and a dominant orientation of the streets in order to detect streets.