Latest Contributions by TimHodson

hi Pascal, Here are the functions. Note there is a slight signature change with addition of the spatial reference parameter. I edited, in place, the calling code in the previous comment:     private bool GetCOGOFromGeometry(Polyline myLineFeature, SpatialReference MapSR, double ScaleFactor, double DirectionOffset, out object[] COGODirectionDistanceRadiusArcLength) { COGODirectionDistanceRadiusArcLength = new object[4] { DBNull.Value,DBNull.Value,DBNull.Value, DBNull.Value }; try { COGODirectionDistanceRadiusArcLength[0] = DBNull.Value; COGODirectionDistanceRadiusArcLength[1] = DBNull.Value; var GeomSR= myLineFeature.SpatialReference; if (GeomSR.IsGeographic && MapSR.IsGeographic) return false; //no SDK support for Geodesics till 2.8 double UnitConversion = 1; if (GeomSR.IsGeographic && MapSR.IsProjected) { //only need to project if dataset is in a GCS. UnitConversion = MapSR.Unit.ConversionFactor; // Meters per unit. Only need this for converting to metric for GCS datasets. myLineFeature = GeometryEngine.Instance.Project(myLineFeature, MapSR) as Polyline; } EllipticArcSegment pCircArc; ICollection<Segment> LineSegments = new List<Segment>(); myLineFeature.GetAllSegments(ref LineSegments); int numSegments = LineSegments.Count; IList<Segment> iList = LineSegments as IList<Segment>; Segment FirstSeg = iList[0]; Segment LastSeg = iList[numSegments - 1]; var pLine = LineBuilder.CreateLineSegment(FirstSeg.StartCoordinate, LastSeg.EndCoordinate); COGODirectionDistanceRadiusArcLength[0] = PolarRadiansToNorthAzimuthDecimalDegrees(pLine.Angle - DirectionOffset*Math.PI/180); COGODirectionDistanceRadiusArcLength[1] = pLine.Length * UnitConversion / ScaleFactor; //check if the last segment is a circular arc var pCircArcLast = LastSeg as EllipticArcSegment; if (pCircArcLast == null) return true; //we already know there is no circluar arc COGO //Keep a copy of the center point var LastCenterPoint = pCircArcLast.CenterPoint; COGODirectionDistanceRadiusArcLength[2] = pCircArcLast.IsCounterClockwise ? -pCircArcLast.SemiMajorAxis : Math.Abs(pCircArcLast.SemiMajorAxis); //radius double dArcLengthSUM = 0; //use 30 times xy tolerance for circular arc segment tangency test double dTangencyToleranceTest = MapSR.XYTolerance * 30; //around 3cms if using default XY Tolerance - recommended for (int i = 0; i < numSegments; i++) { pCircArc = iList[i] as EllipticArcSegment; if (pCircArc == null) { COGODirectionDistanceRadiusArcLength[2] = DBNull.Value; //radius COGODirectionDistanceRadiusArcLength[3] = DBNull.Value; //arc length return true; } var tolerance = LineBuilder.CreateLineSegment(LastCenterPoint, pCircArc.CenterPoint).Length; if (tolerance > dTangencyToleranceTest) { COGODirectionDistanceRadiusArcLength[2] = DBNull.Value; //radius COGODirectionDistanceRadiusArcLength[3] = DBNull.Value; //arc length return true; } dArcLengthSUM += pCircArc.Length; //arc length sum } //now check to see if the radius and arclength survived and if so, clear the distance if (COGODirectionDistanceRadiusArcLength[2] != DBNull.Value) COGODirectionDistanceRadiusArcLength[1] = DBNull.Value; COGODirectionDistanceRadiusArcLength[3] = dArcLengthSUM * UnitConversion / ScaleFactor; COGODirectionDistanceRadiusArcLength[2] = (double)COGODirectionDistanceRadiusArcLength[2] * UnitConversion / ScaleFactor; return true; } catch { return false; } }       Here is the second function for direction unit/format conversions from polar to north azimuth:     private static double PolarRadiansToNorthAzimuthDecimalDegrees(double InPolarRadians) { var AngConv = DirectionUnitFormatConversion.Instance; var ConvDef = new ConversionDefinition() { DirectionTypeIn = ArcGIS.Core.SystemCore.DirectionType.Polar, DirectionUnitsIn = ArcGIS.Core.SystemCore.DirectionUnits.Radians, DirectionTypeOut = ArcGIS.Core.SystemCore.DirectionType.NorthAzimuth, DirectionUnitsOut = ArcGIS.Core.SystemCore.DirectionUnits.DecimalDegrees }; return AngConv.ConvertToDouble(InPolarRadians, ConvDef); }       ... View more