The MapInfo Ruler tool does not give a bearing angle!

How do I calculate the bearing of a line, or between two points?

Solution

To calculate a bearing interactively with a ruler tool, use Discover's

QUERY>Map Object>Location Info

Or to calculate a selected lines bearing and saved in as a attribute use -

QUERY>Map Object>Line Orientation

MapInfo MapCAD, which is now turned on by default, adds a tool under -

SPATIAL>Calculate>Calculate Direction

**This is incorrect. It calculates a mathematical standard cartesian angle, which is counter clockwise from the right hand direction (East).**

To convert this into a GIS bearing, which is clockwise from North (top of map) you need to apply the following -

degResult = 90.0 - mathBasedDeg;

if (degResult < 0)

degResult += 360;

if (degResult > 360)

degResult -= 360;