In 2008, the governments of Papua New Guinea and Australia implemented an agreement to manage the Owen Stanley Ranges region, including the Brown River Catchment and the historic Kokoda Track. The region covers 40 000 square kilometres and stretches from the northern coast and over the mountains down towards Port Moresby. The two governments agreed to work together to manage the natural and cultural resources of the region.
Both governments have a strong interest in the joint venture. The Kokoda Initiative is aimed at managing the Kokoda Track, which is highly symbolic for Australians. For its part, the PNG government is interested in enhancing the quality of life of landowners, conservation of the catchment and building the tourist industry. A second agreement was signed between the two governments in 2010, re-affirming the intention of both partners.
The Australian government, via the CRC for Spatial Information, developed a number of spatial systems and databases to support the landuse planning requirements of the Kokoda Initiative.
Three critical datasets were identified as requirements. The first of these was a high-resolution digital elevation model (DEM) that could be used to derive key attributes of the terrain, such as slope, aspect and drainage, from which an estimate of the susceptibility of a hillside to erosion could be derived. A current landuse map was also considered desirable as was an interim assessment of changes in forest cover and biomass.
To build the DEM, the project team used radar imagery because of the region's persistent cloud cover, which makes optical data almost unobtainable. Radar is also useful because it can see through the tree canopy to determine the shape of the surface of the Earth. The CRCSI used data acquired from the PALSAR instrument carried on the Japanese ALOS satellite and NASA's Earthdata, is derived from its radar imagers.
Land cover mapping was also carried out separately using a data set from the GeoSAR instrument, which is carried on an aircraft operated by Fugro – a global integrator of geospatial services. The GeoSAR data was useful because it combines P-band and X-band radar imagery making it possible to distinguish a variety of land cover types; so forests, plantations and crops, mangroves, clearings and disturbed areas can be readily identified.
With the datasets in place, it was possible to assess the suitability of the ranges and the adjacent high-relief hills and foothills for a number of alternative uses. Economic opportunities such as logging, water supply and electricity generation from hydro-power have been considered. It is possible to provide objective measurements of the susceptibility of the cleared landscape to erosion. By careful manipulation of the data, it is possible to ask questions about whether trekking and tourism can co-exist with these.