Geodesic Buffers generated from Points vs Polylines

Question

When creating geodesic circles in ArcGIS 10, is there a reason why buffering from Point features results in a true geodesic representation, however buffering from a Polyline does not?

I have been using the 'Buffer' geoprocessing tool only.  I noticed when buffering from a polyline, it did not appear to produce a true geodesic buffer.  When I used the 'Feature Vertice to Points' tool to convert the same polyline into points, I then conducted another buffer using the same 'buffer' tool.  This time it yielded a more accurate geodesic buffer.

Why is this so?  Is it an algorithm problem?

JustinOdell · Answer

Thanks Melita.  I'm unsure on the ease of creating a tool that does this, however if anybody else would find a geodesic buffer tool useful for generation from polygons or lines, then you can support the idea here:

http://ideas.arcgis.com/apex/ideaSearchResults?s=geodesic+buffer

MelitaKennedy · Answer

When creating geodesic circles in ArcGIS 10, is there a reason why buffering from Point features results in a true geodesic representation, however buffering from a Polyline does not?

I have been using the 'Buffer' geoprocessing tool only.  I noticed when buffering from a polyline, it did not appear to produce a true geodesic buffer.  When I used the 'Feature Vertice to Points' tool to convert the same polyline into points, I then conducted another buffer using the same 'buffer' tool.  This time it yielded a more accurate geodesic buffer.

Why is this so?  Is it an algorithm problem?

We haven't implemented geodesic buffering for polylines or polygons yet. The first bullet in the usage section of the Buffer Tool talks about when buffers will be geodesic-based.

Buffer Tool help

Melita