Unsupervised classification is a method in which computer image interpretation software separates pixels in an image based on their reflectance values into classes or clusters without any analyst inputs (ERDAS, 1999).
Application of the DPSIR framework to environmental degradation assessment in northern Ghana
Article first published online: 4 OCT 2007
Natural Resources Forum
Volume 31, Issue 3, pages 212–225, August 2007
How to Cite
Agyemang, I., McDonald, A. and Carver, S. (2007), Application of the DPSIR framework to environmental degradation assessment in northern Ghana. Natural Resources Forum, 31: 212–225. doi: 10.1111/j.1477-8947.2007.00152.x
Post classification change detection is used to compare two or more independently prepared classified images to facilitate comparison. The procedure allows areas of change to be identified (Howarth and Wickware, 1981).
- Issue published online: 4 OCT 2007
- Article first published online: 4 OCT 2007
- European Environmental Agency DPSIR environmental assessment framework;
- Participatory GIS;
- Environmental degradation;
- Environmental assessment;
- northern Ghana
In many communities in northern Ghana, the environment has been altered by complex natural and human driven forces with significant impact on the lives of their inhabitants. The need to formulate an improved, holistic and consistent methodological approach to assess the problem is critical for sustainable natural resource management. This paper examines the potential of the DPSIR environmental assessment framework utilizing GIS-based participatory methodology in the assessment of environmental degradation in northern Ghana. Community truthing tools such as key informant interviews, focus group discussions, participant observation and participatory Geographical Information Systems (GIS) were employed as a means of soliciting societal responses integrated to conventional GIS spatial analysis to measure the indicators of the Driving force–Pressure–State–Impacts–Response (DPSIR) assessment framework. Post classification GIS imagery results show a marked natural vegetation decrease of 634 km2 (42%) of the study area with a corresponding increase of 600 km2 (39%) of grasses and built-up and barren environment in the period of 14 years from 1990 to 2004. This is attributed to extreme climatic conditions and human driven causes such as poverty, population growth, migration and land tenure system. Poverty reduction strategies, amendment of the Mining and Mineral Law (PNDC law 153), improvement of the existing land tenure system and the control of migrants and Fulani herdsmen from neighbouring Burkina Faso were some of the solutions selected by the research participants, to be emphasized in the National Environmental Action Plan (EPA Act 490). This paper concludes that the DPSIR environmental assessment framework is an effective means of organizing complex environmental information to facilitate policy decision making.