Calculate Polygon Areas
This tool allows the user to calculate the areas of a selected shapefile and add these to the attributes.
See also the Update Measurements plugin instructions for a plug in that will measure line length, polygon perimeter and area and add these to the attributes.
Click on [GIS Tools]
Click on [Vector]
Click on [Calculate Polygon Areas]
If it cannot detect the shapefile units a warning will show asking if you wish to use the units in the projection. Click OK
The calculate area box appears
Select the layer.
Set the shapefile units
Set the units of the area you want created
If this is the first time, select the 'Use a new field' and give it a new name if required
If there is already an area field, select 'Update an existing Field', and select the field from the list
Click on [Calculate]
Your field will now have the area calculated.
The option to specify decimal places is not in this tool. To specify decimal places, use the Update Measurements Plug-in