1. A method comprising: obtaining, by one or more processors, trajectories represented by a set of points on a map; identifying, by one or more processors, common route elements for the trajectories based on the set of points, each of the common route elements representing a geospatial area in which at least a predetermined number of the trajectories are identical; generating, by one or more processors, simplified representations of the trajectories based on the identified common route elements; obtaining, by one or more processors, a new trajectory represented by a new set of points on the map; updating, by one or more processors, the common route elements based on the new set of points, wherein updating the common route elements comprises incrementally updating the common route elements by: in response to determining that a first portion of the new trajectory is covered by at least one common route element, representing the first portion with the at least one common route element; in response to determining that a second portion of the new trajectory is covered by none of the common route elements, generating a new common route element to represent the second portion, and in response to failing to generate the new common route element, generating a new individual route element to represent the second portion; and updating, by one or more processors, the simplified representations based on the updated common route elements.