OrdnanceSurvey
Orientation/Flow arrows
The orientation attribute is defined in the Technical Specification as "tenths of a degree anticlockwise from due east".
The GeoServer SLDs have a flow arrow SVG that points from right to left, and use orientation * 0.1. An orientation of 0 would imply drawing the symbol as defined, with no rotation, ie due west.
The Cartographic Style Definitions have a flow arrow that points from left to right.
These seem to be contradictory. Can you confirm which is correct?
Hi Martin, sorry for the lateness in my reply. The specification is correct but the SLD needs to be amended to address this. Ill update the SLD as soon as possible. Thanks.
As you say the SVG for the flow arrow draws from right to left when it should point left to right. To combat this and ensure the arrow points the right way the expression within the SLD needs to read 90 - "orientation" / 10.