A COMPUTERISED geographical index of buildings, landmarks and major roads yesterday came into operation to improve the speed with which police respond to 999 emergency calls. The gazeteer contains about 40,000 residential and business titles. It has taken a team of officers nine years to input the detailed location information. Police chiefs hope the data will see inquiries answered within seconds - helping overcome concerns that the 999 dispatch was not operating at its best. Staff Officer for the Information Technology Branch, Superintendent Neil Christie, said the equipment would improve the performance and reach of the force's command and control operations. Mr Christie conceded it would take time to train all officers. But the equipment would provide visible benefits - including the ability to have a tourist's plea for directions answered immediately by a beat officer using the radio. ''This is a means whereby we can identify the location of a police beat or division closest to the incident,'' Mr Christie said. ''The whole philosophy behind this operation is to get police officers to the scene quicker than we can at the moment. And, if it is an incident in progress, that pushes up our chances of having someone arrested. ''Obviously, the system will stand or fall on its speed and accuracy. ''We will also, in time, be able to build up a complete picture of where most crimes occur.'' This would see force managers being able to chart the frequency, location and time of criminal offences - and, obviously, assist in the better deployment of officers to ''black spot'' areas. The gazeteer is bilingual and is capable of interpreting data in English and romanised Cantonese. It also includes landmarks on outlying islands. Even if an incomplete location or landmark is given to the operator, the machine is able to recite various options - reducing delay.