I am using qgis version 1.8.0. My project contains tiff and several "shape" layers. The CRS is WGS 84 (EPSG:4326). I am attempting to measure the areas of the layer polygons. However if I click on the symbol "Measure area", I am getting a message. It keeps telling me the measurements are problably wrong. (Testing this statement by measuring leads to enormous but wrong values) It suggests to define a coordinate system in project properties. I have been trying this serveral times - with no results. Furthermore I read "Working with Projections" and "Measuring" in the User guide (http://docs.qgis.org/user_guide/html/en/user_manual/introduction/general_tools.html and http://docs.qgis.org/user_guide/html/en/user_manual/working_with_projections/working_with_projections.html). Also after adjusting all other CRS settings the problem stays.
What should I do ?
Thank you for your advice