Some operation may have different semantic depending on which boundary node rule is applied. See http://www.vividsolutions.com/jts/javadoc/com/vividsolutions/jts/algorithm/BoundaryNodeRule.html for background information. GEOS C-API only expose boundary-node-rule in the GEOSRelateBoundaryNodeRule, introduced in 3.3.0. But more functions would be affected by such rule these are: * Relate (we have GEOSRelateBoundaryNodeRule since 3.3.0) * Boundary * isSimple * Touches * Within * Contains It would be useful to expose a way to specify the boundary node rule for each of the above operations