Most of the native vegetation in the Blue Mountains City has been mapped using orthorectified infrared aerial photographs flown at a minimum resolution of 1:6000 from December 1998 to January 1999. The far western and southern parts of the Megalong Valley were mapped separately using orthorectified truecolour aerial photography flown at 1:50,000 in 1998. At Mount Tomah, mapping was undertaken at 1:2500 due to the complexity of the geology, disturbance histories and thus variations in vegetation structural classes. On the other basalt areas and in most of the sandstone terrain, a scale of 1:3500 -; 1:6000 was used. In the case of small, very linear and/or poorly delineated vegetation types, scales as fine as 1:750 were employed using the infrared imagery.; ; VIS_ID 2239