Date of Award

Fall 2006

Project Type


Program or Major

Natural Resources: Forestry

Degree Name

Master of Science

First Advisor

Russell G Congalton


More than 60% of land in New Zealand has been converted from native forests to residential areas, agriculture, or forest plantations. Settlers brought many species of plants and animals to New Zealand. Many native species were unable to protect themselves from these new predators, causing numerous extinctions. In light of this rapid decline in biodiversity, the New Zealand government has attempted to mitigate the destruction of endemic flora and fauna through both new environmental policies and intensive land management. Land management techniques include the restoration of developed land and the protection of remaining areas of native forest. Monitoring of restoration efforts is important to the government and organizations responsible for this work. Using remotely sensed data to perform change analysis is a powerful method for long-term monitoring of restoration areas. The accuracy of maps created from remotely sensed data may be limited by significant terrain variation within many of the restoration areas. Landcare Research New Zealand has developed a topographic suppression algorithm that reduces the effects of topography. Landsat ETM+ imagery from November 2000 was processed with this algorithm to produce two images, an orthorectified image and a terrain-flattened image of a 50-km by 60-km area near Wanganui, New Zealand. Using GLOBE reference data collected on the ground in September/October 2004 and additional reference data photointerpreted from aerial photography, thematic maps were created using unsupervised, supervised, and hybrid classification methods. The accuracy of the thematic maps was evaluated using error matrices and Kappa analysis. The different image processing techniques were statistically compared. It was determined that the topographic-flattening algorithm did not significantly improve map accuracy.