While importing KML files from google Earth to Quantum GIS, the scale is not being projected properly and the area of a particular selected feature is not being calculated in the attribute table by the field calculator. How can the area of a selected feature be calculated by the field calculator, as right now it is showing up zero as the value?
KMLs only support WGS84 CRS which uses degrees as unit of measurement. Field Calculator therefore calculates area in square degrees. If the polygons are small, the area will be almost zero.
Change to a different file format, reproject the data and calculate the area.