Title

Victorian Bushfires Severity Map 2009 (Polygons) 

Alternate title

FIRE_SEV09_POLY 

Resource Type

Dataset  

Supplemental Information

Related Documents: None 

Status

Completed  

Time period

2009-03-272009-07-17 

Spatial representation type

Vector  

Horizontal Accuracy

25m  

Code

4283 

 

Maintenance and update frequency

Not planned  

Topic category

• Environment

Use limitation

Data is not to be distributed without authorisation from the Department of Sustainability and Environment (DSE), Victoria 

Classification

Unclassified  

Statement

Dataset Source: The dataset is a derived product from raw satellite data as acquired by the SPOT 4 and 5 Satellite. The imagery is a product orthorectified by DSE. Calibration of the imagery has been limited to the application of the gain values as supplied with the SPOT images for the post fire scenes while the pre fire scenes were spectrally matched to the post fire scenes through the use of "invarient" targets including water bodies, highly reflective features and unchanged forests. Where multiple post fire images are mosaiced, the central scene or scene of best quality is used as the reference to which all other scenes are matched. A fire severty index was prepared through the digital processing of the pre fire and post fire imagery. The analysis is largely based on a ratio of the SWIR and NIR bands though a Transform Vegetation Index (TVI) ratio was used on Wilsons Promitory. The index for each region was then compared against ground information and split into five classes that can be statistically justified from the six descrete classes supplied by DSE. The Churchill, Dargo, Redesdale and Horsham areas do not have any ground survey points available for verification. The Churchill fire severity classes were extrapolated across from the Kinglake and Bunyip SPOT scenes while all other areas are classified through visual interpretation of the imagery. In wooded areas within Dargo, Redesdale and Horsham, only severity classes one to three have been interpreted with all other wooded areas left as unclassified burnt woodlands. The Redesdale and Horsham areas are dominated by grassland burns with grasslands either within classes seven or eight dependent on their likelyhood of actually being burnt. Noise filtering has been performed using a 3X3 majority filter. This filter simply applies the majority value within a 3X3 window to the central pixel thus removing the majority of speckle within the classification. A basic conversion to vector has been undertaken with no additional simplifications performed. The constructed attributes table contains a measure of area (in hectares) and a class description. Dataset Originality: Derived 

Classification

Unclassified