simplification using a %-like value

[mattijn]

This package provide options to simplify linestrings. The presimplify function does this before computing the topology (not really recommend to use!) and the toposimplify function does this after computing the topology (you probably want this).

Line simplification can be done using the Douglas-Pecker or Visvalingam-Whyatt algorithm. They both operate through an epsilon or tolerance parameter. Depending on the algorithm it represent distance (DP) or area (VW).
Therefor the required tolerance in each situation is hard to decide since it is implicitly depending on the projection as well (eg. meters or degrees).

Mapshaper provide the option to reduce the linestring by a percentage of points. It would be nice to have this possibility as well for the functions presimplify and toposimplify .

A much better explanation of the differences of the epsilon parameter between the DP and VW algorithm is explained by @martinfleis here: #44 (comment) and here: http://martinfleischmann.net/line-simplification-algorithms/

[mattijn]

This issue is raised upstream: urschrei/simplification#11