Mobile vehicles operating in urban navigation applications can achieve high integrity localisation with high accuracy by using maps of the surroundings. To accomplish this, the map should always have an accurate representation of the environment. Thus, it is necessary to detect and remove the map components that no longer exist in the current environment. This maintains the map compactness and dependability while simplifying the data association problem. This paper addresses the problem of deletion of transient map components by taking advantage of the geometric connection between the map and agent poses in order to establish and update the visibility of each feature. Once the map is created an initial visibility vector is associated with every map element and updated over time. The visibility of a map element which no longer exists is reduced and ultimately removed from the map. We demonstrate our approach in a 2D feature-based map composed of poles and corners extracted from information provided by a Iidar sensor. The experimental results show the map update using a seven-month data set collected in the University of Sydney campus.