On 27 June 2017 at 09:28, Nyall Dawson <[email protected]> wrote: > Hi all, > > As you may be aware, I've been working on rebuilding the backend of > Processing in c++ and refining how it operates. > > As part of this I'd like to clear up the list of existing algorithms > and also refine how they behave. This list of "QGIS" algorithms has > grown organically during the 2.x cycle, and there's now numerous > oddities in the selection of available algorithms and their options. > > This discussion relates to the "Singlepart to Multipart" algorithm. I'd like > to: > > 1. drop the option for "unique ID field". This option is used to > 'collect' the geometries from features with matching ID together into > a single output geometry. I'd like to remove this option and make the > "Singlepart to Multipart" algorithm purely upgrade geometry types from > single part to multipart, without adding any extra parts or collecting > geometries. So basically the algorithm would upgrade single parts to > collections containing just a single part - the equivalent of PostGIS' > ST_Multi function. > > 2. Add a new algorithm "Collect parts" which does what the option in > Singlepart to Multipart used to do. This would collect all features > with matching fields (you could select more than one field - unlike > the current Singlepart to Multipart option) and output collection > features containing these geometries. Just like dissolve, but without > the dissolving of overlapping parts. >
This proposal is now implemented in https://github.com/qgis/QGIS/pull/5129 Nyall _______________________________________________ QGIS-Developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
