Bug #46885 Polygon/line generalization feature
Submitted: 24 Aug 12:23 Modified: 24 Aug 13:48
Reporter: John Powell
Status: Verified
Category:Server: GIS Severity:S4 (Feature request)
Version: OS:Any
Assigned to: Alexey Botchkov Target Version:
Tags: line, polygon, smoothing, generalization
Triage: Needs Triage: D5 (Feature request)

[24 Aug 12:23] John Powell 
Description:
This is a request for a polygon/line generalization algorithm. The generally used
algorithm is Ramer-Douglas-Peuker. This algorithm can distort topology, producing
intersections between lines in the generalized polygons that were not present in the
original polygons. For this reason, two version are required:

1) Generalization
2) Generalization with an a posteriori check that the original topology has been
maintained.

In postgres these functions are called ST_Simplify and ST_SimplifyPreserveTopology, while
Oracle uses simplify_geometry and both use Douglas-Peuker. For the purposes of
consistency, the term simplify should be used in some form.

How to repeat:
Feature request, so can't be repeated.
[24 Aug 12:42] John Powell 
The input to this function would be the polygon/line to be simplified and some tolerance
number.

Currently MySQL only supports projected/planar coordinates. Eventually, once
geographic/geodetic coordinates are supported, this function would have to be modified
somewhat in the calculation of distance as applied to tolerance.
[24 Aug 13:48] Valeriy Kravchuk 
Thank you for the feature request.