Wanda Norman wrote > I tried: ( "aspect at 1" < = 90) OR ( "aspect at 1" > = 270) - I get > Expression is not valid. Hi Wanda, have you tried not putting spaces between the characters "<" and "=" and between ">" and "="? Regards. Andrea -- Sent from: http://osgeo-org.1560.x6.nabble.com/QGIS-User-f4125267.html