{"comment":{"url":"https://api.github.com/repos/nyalldawson/QGIS/comments/14396761","html_url":"https://github.com/nyalldawson/QGIS/commit/596b56c44130f44a2d3d4e0c43c231d7a92d921d#commitcomment-14396761","id":14396761,"user":{"login":"nyalldawson","id":1829991,"avatar_url":"https://avatars.githubusercontent.com/u/1829991?v=3","gravatar_id":"","url":"https://api.github.com/users/nyalldawson","html_url":"https://github.com/nyalldawson","followers_url":"https://api.github.com/users/nyalldawson/followers","following_url":"https://api.github.com/users/nyalldawson/following{/other_user}","gists_url":"https://api.github.com/users/nyalldawson/gists{/gist_id}","starred_url":"https://api.github.com/users/nyalldawson/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nyalldawson/subscriptions","organizations_url":"https://api.github.com/users/nyalldawson/orgs","repos_url":"https://api.github.com/users/nyalldawson/repos","events_url":"https://api.github.com/users/nyalldawson/events{/privacy}","received_events_url":"https://api.github.com/users/nyalldawson/received_events","type":"User","site_admin":false},"position":10,"line":84,"path":"python/plugins/processing/algs/qgis/PointsInPolygon.py","commit_id":"596b56c44130f44a2d3d4e0c43c231d7a92d921d","created_at":"2015-11-14T09:33:31Z","updated_at":"2015-11-14T09:33:31Z","body":"Not really. All the complex geometry operations (like intersections, relation tests, buffers, etc) are handled by an external library (\"geometry engine\" in QGIS). At the moment in QGIS this is all handled by GEOS (this is how it was with the old geometry too). In the new geometry classes, calling `createGeometryEngine` will return a QgsGEOS object which allows you to more precisely control how these GEOS operations are handled. In this case, we create the engine to allow us to call `prepareGeometry`. This allows GEOS to use prepared geometry relation operations, which are dramatically faster for times when one prepared geometry is tested against multiple other geometries (See https://trac.osgeo.org/geos/wiki/PreparedGeometry)"}}