Title

Victorian Bushfires Severity Map 2009 (RASTER GRID) 

Alternate title

FIRE_SEV09 

Supplemental Information

Related Documents: None 

Status

Completed  

Horizontal Accuracy

25m  

Code

4283 

Maintenance and update frequency

Not planned  

Title

DIGITAL ESRI GRID 2 

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. Dataset Originality: Derived 

Classification

Unclassified  

Attribute Quality

Comments

The break up into the assigned classes within the classification is based on ground truthing and air photography interpretation information as supplied by DSE. Though a full statistical analysis has not been performed on the accuracy of the classes relative to the ground information, it is anticipated that classes 1 and 2 will contain over 80% of all ground information relevant to those classes, class 3 will include the majority of of class 3 ground sites, while classes 4 and 5 (containing severity classes 4 and 5a, and 5b will require more statistical assessment to further comment. 

Positional Accuracy

Comments

There are three different data sources that are reliant on spatial position used to derive the product, however, the primary data source (satellite imagery) is an orthorectified product as supplied by DSE Victoria. This product has been found to be accurate to within one hundred metres against all other reference information available. Largest issues are seen in scenes taken at shallow angles and in steep terrain. 

Conceptual Consistency

Comments

Not specified 

Missing Data

Comments

Complete Completeness Verification: Incomplete 

Excess Data

Comments

Complete