The invention is the reference implementation of the Unique Building Identifier (UBID) specification [1]. The reference implementation includes the "buildingid" command-line executable that supports comma-separated values (CSV) files and Environmental Systems Research Institute (ESRI) Shapefiles and provides UBID encoding and decoding, UBID cross-reference and CSV file to/from ESRI Shapefile conversion capabilities. A UBID is a short string of characters (typically, less than 24 characters) that encodes of the center of mass (i.e., centroid) and cardinal direction extents of a land lot on the surface of the Earth. Examples of land lots include building footprints. The input for encoding a UBID is 6 numbers: the latitude and longitude coordinates of the centroid of the land lot and the latitude and longitude coordinates of the south-west and north-east corners of the minimal bounding box of the land lot. In the UBID specification, latitude and longitude coordinates are encoded as short strings using the Open Location Code (OLC) grid reference system [2]. The OLC grid is a recursively-subdivided, rectangular grid. At each level of the recursion, the grid has higher resolution. For example, in the 5th layer, the area of each OLC grid cell is approximately 14x14 meters (at the Equator). The OLC grid also has a "refinement" capability. For example, in the 5th layer with 1 refinement, the area of each OLC grid cell is approximately 2x3 meters (at the Equator). The inventive feature of UBID is that the extents of the OLC grid cell are used to measure the cardinal direction extents of the land lot. In the UBID specification, each extent is the smallest number of OLC grid cells that are required to completely cover a given line. For example, the line from the northern edge of the OLC grid cell to the northern edge of the minimal bounding box of the land lot. (In fact, the selection of OLC is arbitrary. The UBID methodology being applicable to any rectangular grid reference system with a string representation for latitude and longitude coordinates.) Since extents are measured "OLC grid cell units," the UBID specification is robust with respect to the underlying geographic coordinate system (in this case, WGS-84) and its behavior with respect to the position of a given land lot on the surface of the Earth (e.g., at the poles). UBIDs can be assigned to any land lot. (In fact, UBIDs can be assigned at any location rectangle, including those at sea!) One land lot can be assigned multiple UBIDs, where each UBID is dependent upon the OLC resolution. Hence, the OLC resolution itself can be selected with respect to the requirements of each use case. The UBID cross-reference capability of the "buildingid" command-line executable can be used to decide if two UBIDs are assigned to the same land lot or if two UBIDs have an "intersects" and/or "contains"/"within" relationship. [1] https://github.com/pnnl/buildingid [2] https://github.com/google/open-location-code