I have an orientation raster layer in QGIS. In band 1 I have the orientation values, wich are between 0º and 360º. Is 0º the North orientation an 180º south??
I would have assumed the same as you did, that 0 degrees is north and 180 degrees is south, just as it works on a compass. But according to Wikipedia,
Modern digital GIS maps such as ArcMap typically project north at the top of the map, but use math degrees (0 is east, degrees increase counter-clockwise), rather than compass degrees (0 is north, degrees increase clockwise) for orientation of transects. Compass decimal degrees can be converted to math degrees by subtracting them from 450; if the answer is greater than 360, subtract 360.