I have some VB.NET code which is constructing a line piece by piece from a set of coordinates in a table. I was creating the separate iLine and then adding those to a Path object. Once the series of point composing the line is finished then I add that Geometry into a Polyline. And that works. It has recently transpired that creating that I want to create the line as geodesics or loxodromes, depending upon the line. I found the ConstructGeodeticLineFromPoints member of the IConstructGeodetic interface. But this creates Polylines so the previous code I had with Paths is no longer working. I am trying to Union my spearate geodetically accurate polyline segments with a TopologicalOperator but that is taking a whole lot longer and runs into problems after a while. I was trying to look into SegmentCollections and GeometryCollections to mimic what I had been doing previously with iLines and Paths, but it doesn't seem to be working. Does anybody have any experience with easily joining together polyline elements programatically together?