Abstract: A computer system and method for performing 3D geolocation within an urban environment to at least a building floor level by combining geocoded locations with local dimensional data available from municipal agencies processed to calculate estimated elevation of building floors in a target building. The local dimensional data is building inventory information that includes the ground elevation of the target building, the number of above-ground floors in the target building and the height of the target building. The system is configured to calculate the building floor level of a particular floor in the target building from the local data. Standard equations for estimating the height of a building are adapted to generate the elevation of the particular floor within the target building relative to the ground elevation of the target building.