A computer implemented method for determining a requested map location includes providing a database holding a plurality of {HEAD ~ map objects} having respective descriptors and {TAIL ~ loci} 
having
A computer implemented method for determining a requested map location includes providing a database holding a plurality of { HEAD ~ map objects } having respective descriptors and { TAIL ~ loci }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL