AnsweredAssumed Answered

True Curves = True Evil

Question asked by geonetadmin on Feb 7, 2012
Latest reply on Jun 9, 2017 by Caleb1987
Original User: csny490

I am having some issues with "true curve" features.. true curves being polylines or polygons features that have loopy/circular Bezier curve-type geometry... These features appear to be fully supported in v9.3+ and actively created/preserved by many geoprocessing tools such as Buffer, Clip, Union, etc. However, I am finding that these true curve features are causing the creation of many small holes in my overlays (see first attachment). When present, these "holes" always appear adjacent to true curve geometry inputs in my overlay. I am guessing the issue is that the equations that represent the curve feature aren't being stored/interpolated at a high enough decimal precision so as to provide the "correct" output node locations for the overlaid geometry (see second attachment). My overlays are generally being done at a xy res of .0005 Meters and a xy tol of 1 ft (to minimize slivers). Granted that the "hole" issue is minimized by using a finer xy resolution.... but it seems to me the overlay algorithm should ensure correct/precise polygon adjacency and guard against these holes being created where no holes existed in the input features.

Some comments/questions:
1. I hate true curves, and wish they would just go away.
2. Is there still a not way to stop true curve features from being created in FGDBs / SDE (this is a rhetorical question)? For example, some way to specify that my buffer output is NOT to have curve features?
3. FYI to ESRI, these curve features are causing errors (holes) in the outputs of the overlay tools.
4. I bet a lot of GIS people don't know that these curve geometries are being created/propagated in the geoprocessing tools. It would be good to know under what tools/conditions the curve geometry is created and/or propagated.

Seems the only way I have come up with to avoid this issue is to export the feature classes that contain true curves to a shapefile, and then reimport them back to a FGDB.... I see the Densify tool now standard in v10.0 will convert the curve features to densified geometry (aka "traditional GIS geometry"), but it's a pain to have to do this extra step when it used to not be necessary... and how are you supposed to know what features have curve geometry in the 1st place? There does not appear (?) to be a way to discern true curve geometry via arcpy/Python scripting. Like I said, a Envr. setting to control this behavior (creation/propagation of curve features) would be ideal...