This adds a configuration interface and renderer that makes it easy to
put all the pieces together which are required to get a 2.5D effect.
It allow for configuring some of the styling and is meant to create an
easy-to-use setup.
Since every part of the system is built around QGIS' internal rendering
and symbology engine, there is much to fine tune. To get all the
possibilities, just change the renderer to a graduated, categorized or
single symbol renderer upon creation and you will find full access to
improve the style to your needs.
Funded by
* Regional Council of Picardy
* ADUGA
* Ville de Nyon
* Wetu GIT cc
New variables for:
- @qgis_os_name: eg 'linux','windows' or 'osx'
- @qgis_platform: eg 'desktop' or 'server'
- @user_account_name: current user's operating system account name
- @user_full_name: current user's name from os account (if available)
Sponsored by Andreas Neumann
For Oracle provider, giving a quoted uniqueColumn in a uri to create a
QgsVectorLayer results in an invalid layer.
To fix it, strip '"' is applied to unique col.
[FEATURE] Tracing of features (digitizing)
Tracing can be now used in various capturing map tools (add feature, add part, ...) including reshape and split tools.
Tracing is simply a new mode for these tools - when tracing is not enabled, the tools work as usual. When tracing is enabled (by clicking the new magnet icon or pressing T key), tools switch to tracing behavior:
- first click on a vertex/edge (must be snapped!) will start tracing - moving mouse on top of the map continuously updates the trace
- next click will confirm the trace and mark start of a new trace Tracing can be enabled/disabled anytime even while digitizing one feature, so it is possible to digitize some parts of the feature with tracing enabled and other parts with tracing disabled.
Tracing respects snapping configuration for the list of traceable layers.
If there are too many features in map display, tracing is disabled to avoid potentially long tracing structure preparation and large memory overhead. After zooming in or disabling some layers the tracing is enabled again.
Internally, things work like this:
- when tracing is requested, linestrings are extracted from vector layers, then noded (using GEOSNode to resolve all intersections) and finally a simple planar graph is built (vertices + edges)
- when tracing, endpoints are temporarily added to the graph (if not equal to one of existing vertices already) and Dijkstra's algorithm is run to get shortest path
Original specs for the curious ones (the interaction with QGIS is slightly improved from what has been specified): http://www.lutraconsulting.co.uk/crowdfunding/autotrace-phase-2/specification.pdf
During rendering, two new variables will be available:
* `geometry_part_count`
* `geometry_part_num` (1-based index)
Useful to apply different styles to different parts of multipart
features
