Convertion degree to azimuth

Discussion created by oyleiste on Apr 6, 2013
Latest reply on Apr 11, 2013 by a-subbotin
Dear All,

I have 2 points which creates a line. I want to get angle of line and then draw another line with +30 degree. I can do it but I always get 7-10 degree more than actual angle.

I get distance between 2 points using IMeasurementTool.ConstructByPoints, then I get angle using IConstructAngle.ConstructLine. Here I have angle and distance between 2 points. Now, I'll give ConstructByPointDistAngle first point, distance and angle to get second point. Now I calculate angle between first point and result point of ConstructByPointDistAngle but I get angle with 8.266233055077116 degree difference.

I think I'm not convert degree to azimuth correctly. Any idea?

FYI: azimuth is degrees clockwise from north

Here is my working code with comment and Debug results. Red texts are debug results.

PointClass p1 = new PointClass();
PointClass p2 = new PointClass();
// Add data to points for test
p1.PutCoords(34.481560, 41.515391);
p2.PutCoords(34.702832, 41.795668);

ILine lineForAngle = new Line();
IMeasurementTool measurementTool = new MeasurementToolClass();

measurementTool.ConstructByPoints(p1, p2);
// Here we calculate distance between two points: (p1, p2)
double distance = measurementTool.Distance;

GeometryEnvironment geoEnv = new GeometryEnvironment();
IConstructAngle angleCalculator = (IConstructAngle)geoEnv;

lineForAngle.PutCoords(p1, p2);
// Here we calculate angle of line between (p1, p2) and the positive x-axis
double angle = angleCalculator.ConstructLine(lineForAngle);
// Convert radian to degree
angle *= 180 / Math.PI; // = 51.709836807757121 Degree
// Convert angle to azimuth (still degree)
angle = 90 - angle;     // = 38.290163192242879

// Here I give first point (p1), azimuth and distance to get p2
measurementTool.ConstructByPointDistAngle(p1, distance, angle);

geoEnv = new GeometryEnvironment();
angleCalculator = (IConstructAngle)geoEnv;

// I put p1 and result point of measurementTool which is a point
lineForAngle.PutCoords(p1, measurementTool.ToPoint);

// Now I have calculate angle between p1 and result of measurementTool
angle = angleCalculator.ConstructLine(lineForAngle);
angle *= 180 / Math.PI; // = 43.443603752680005

// first angle - result angle:
// 51.709836807757121 - 43.443603752680005 = 8.266233055077116