Buffering Problem

Discussion created by sjohnstone on Mar 30, 2011
Latest reply on Apr 5, 2011 by mstjernholm
I am currently having some problems with the results of a buffering operation on a Line.  I am specifying the input coordinates with a spatial reference of WGS84 (4326), the output of the same value and specifying the buffer spatial reference as the projected web mercator (102113) and specify the buffer distance of 1500m.

When I get the result I then compare the original coordinates with the buffered coordinates and calulate the distance between them.  When the original line is near the equator it seems fine but as I repeat the buffer operation on lines further north there seems to be some distorition in the buffered polygon.  For example there are cases where the buffered points are only around 1100m away from the input point (at around 80 degrees latitude).

Does anyone understand why I am getting these distorted results?  Also I have tried buffering with  Equidistant Conic and an Azimuthal Equidistant projections (as suggested in the documentation).  This helped a bit but not much. 

Any help will be greatly appreciated.