Remote sensing in rehabilitated areas

Northwest Australia Vegetation Recognition

About 50 kilometres (31 miles) off the northwest coast of Australia is the country’s largest onshore oil production site. For over 15 years our field teams have been there conducting soil and ecological investigations to support rehabilitated areas—but in recent years, we’ve been investigating a new opportunity for environmental assessment.

Remote sensing techniques—particularly using aerial imagery and object-based image analysis (OBIA)—have been used in many different fields to collect data. Here, it would be implemented through yearly aircraft flyovers and used to complement the existing on-site revegetation monitoring. We pitched the idea to our project partners, and with their library of high-resolution imagery, pretty soon we were monitoring larger areas, reducing costs, and improving field team safety. Using OBIA, the imagery is segmented into objects with similar spectral reflectance (colour, brightness), shape, and size. This allows cover values to be attributed to specific classes such as grass species, shrubs, and bare soil.

The result? We’ve established that with appropriate on-ground information about the vegetation, analysis of high-resolution aerial imagery can provide accurate estimates of vegetation cover, even for some individual species. We are now routinely using OBIA in the area to monitor vegetation status on rehabilitated sites. In addition, we are exploring the potential to use the technology to detect potential environmental impacts through changes in vegetation.