III Identification of Vegetation Communities
Using existing information from previous vegetation studies, native vegetation types that occur in the Blue Mountains have been described to provide a standard description of vegetation communities that abates differences between previous studies. The vegetation types correlated with vegetation structural information

Identify vegetation communities. Vegetation structural information is to be based on the structural classification system devised by specht (1970).

Vegetation Description + Vegetation Structure = Vegetation Community
The vegetation communities located within the study for the purpose of this paper were :

• Eucalyptus piperita-Angophora costata Open-forest(Y)
• Eucalyptus piperita-E. radiata Open-forest(Q)
• Eucalyptus piperita-E. sieberi Open-forest/Woodland(P)
• Eucalyptus manifera-E. radiata Woodland (M)
• Eucalyptus sclerophylla Woodland/Low Woodland (L)
• Montane Health (H)
• Blue Mountains Sedge Swamps (S)
• Escarpment and Rock Outcrop Vegetation
• Creekline Vegetation

IV Vegetation Mapping
Ortho-rectified (1:6000) infra red images of the Blue Mountains city taken in 1999 are used in the present study. The present study is to develop an algorithm that can map different vegetation communities accurately. Hence, as a test case an Infrared Airphoto that covers an area of 1.3 x .9 km2 and that has some groundtruthed information of vegetation is chosen. It consits of 6247 lines and 9218 columns with a resolution of 0.137 metre. The IR image has three bands which have information recoreded using wavelengths from Near Infrared, Visible Red and Visible Green electromagnetic spectrum. The size of the file is 172.75 MB. An index map of the study area is shown in Figure 1.


Figure 1: Index map - North Katomba
4.1 Distortions or noises introduced in Aerial Photographs
The following are some of the noises that may be introduced into IR Aerial Phtographs.

1. Possible inhomogeneity of the recording medium, photographic emulsion (silver halide crystals held by a solidified gelatin) coated on a base or support.
2. Inconsistency in film development process
3. Over or under-exposure time in printing the photo
4. Instability of the aircraft (altitude, pitch, roll, yaw)
5. Position of the Sun at the time the photo was taken
6. Exposure fall off which is the variation in focal plane exposure purely associated with the distance an image point is from the image center. (Vignetting effect) (Lillesand and Kieffer, 1994)

Of all the possible noises introduced in the IR Airphoto, exposure fall of (vignetting effect) maybe the most important. Though there seems to have slight increment in color brightness towards the bottom-right corner of the Airphoto, the RGB composite of the original IR Airphoto (Fig. 2) does not indicate to have vignetting effect. Traverses from the top-left of the image (point A) to the bottom-right (point B) of the three bands (NIR, VisRed, VisBlue) (Fig. 3) also do not indicate to have color increment or decrement from top-left to bottom-right of the image.


Figure 2. RGB composite of original IR, VisRed, VisGreen Bands of IR photo. (A-B is the traverse line of Figure 3.)

Figure 3. Spectral reflectance of Red Layer (NIR-Band1), Green Layer (VisRed-Band2) and Blue Layer (VisGreen-Band3) of traverse A-B on Figure 2.
4.2 Processing Original dataset
An Unsupervised Classification was carried out on the original 3 bands of the IR Airphoto. A standard deviation of 4.5 and a minimum distance between class mean of 3.2 were used in the classification. The classified image with five classes (Fig. 4) gives some classes that correspond to field data. The Bare Ground (B) was clearly mapped. However, other classes such as Swamp(S), Tall Open Forest/Open Forest(P) are not clearly defined.


Figure 4. Five classes (Light Brown, Dark Blue, Cyan, Yellow and Green) of the original IR photo using Unsupervised classification. Bare Ground (B), Tall Open Forest/Open Forest (P), Swamp (S), Woodland (L-Eucalptus sclerophylla), Woodland (M-Eucalyptus Manifera) and Open Forest (Q) are field classes, displayed as vector for comparison.