Category:Angle Conventions

Maps expressing directions may use different conventions according to the field of study they are used in. The "GRASS" convention is 'theta CCW from the +x axis' (i.e. mathematical|Cartesian convention), which means CCW from E and pointing TO the direction (aspect, flow), whereas when dealing with meteorological data, for example, wind is usually expressed CW from N and pointing FROM where wind blows. Some modules currently adopt different angle conventions, therefore it is always necessary to be aware of which convention the direction maps are expressed in.