I am using Qgis 1.7.4 to calculate the area of polygons. My shapefiles have been projected using the coordinate system WGS 1984 UTM fuseau 35 Sud, but my area calculations are still displayed in degrees. how do I get them in metres?
You have to set your Project CRS also to UTM fuseau 35 Sud (Settings/Project Settings/CRS). CRS for shapefile and project may differ, but measuring is always done in project CRS.