[Qgis-psc] Grant report: Rework handling of multi-layer, mixed-format datasets

[Nyall Dawson]

On Wed, 28 Jul 2021 at 14:02, Nyall Dawson <nyall.dawson at gmail.com> wrote:
>
> Hi lists,
>
> Just reporting in the conclusion of the grant work: "Rework handling
> of multi-layer, mixed-format datasets". You can read more about the
> motivation behind this work at
> https://github.com/qgis/QGIS-Enhancement-Proposals/issues/216
>
> While the work was partly motivated as an opportunity to clean up some
> older parts of the QGIS codebase which were fragile and had low test
> coverage, it has also resulted in many improvements and polish in the
> QGIS user interface. Specifically:
>
> - There's a much improved dialog shown when a user has to pick from
> multiple layers from a dataset dropped onto QGIS. The dialog will
> populate in a background thread, avoiding the UI hangs older QGIS
> versions experience when scanning for layers in large files. The
> dialog shows a unified view of all layers in the dataset, regardless
> of whether they are vector, raster or mesh layers. There's also a new
> "filter" widget allowing users to quickly find matching layers in
> larger datasets.
>
> - The browser view of files and file-based datasources has been
> reworked. You'll no longer see duplicate entries for the same files
> when these files can be read as either raster/vector/mesh layers (e.g.
> for netcdf files, geopdf files and other mixed-format types). A lot of
> consistency has been added to the right click actions you see when
> interacting with file based items, with many bugs fixed along the way.
>
> Under the hood, we've now got a flexible API for querying sublayers of
> a dataset which can be easily extended to new providers so that they
> automatically participate in the unified sublayers dialog and browser
> items. It's all protected by a huge number of new unit tests, the
> majority of which cover critical functionality which was previously
> not being tested.

Oh, I forgot another cool new feature -- when dragging and dropping a
geopackage onto QGIS, the dialog showing layers will also show any
embedded projects in that gpkg, making it MUCH easier to open them!

Nyall