[elevation profile] add tolerance for lines and polyons (Request in QGIS)

[qgis-bot]

Request for documentation

From pull request qgis/QGIS#54964
Author: @benoitdm-oslandia
QGIS version: 3.34

[elevation profile] add tolerance for lines and polyons

PR Description:

This PR adds the support to tolerance for lines and polygons by using a buffer.

• some lambda functions have been moved to member functions to increase the readability
• add some tests with tolerance
• some minor fixes and refactor

Here is a screencast of a sample project from the master:

and the same version with ours fixes (more zoomed in the elevation profile tool to show the captured lines):

Extruding closed polygons is not trivial because it is equivalent to representing a 3D object (like a 3D closed polygon reprojected into a 2D closed polygon in the elevation profile tool + the extrusion dimension). We are still working to find a good solution but right now the polygon extrusion is not showing when tolerance is enabled.

cc @ptitjano @lbartoletti @jmkerloch @troopa81

Funded by CEA/DAM @renardf

Commits tagged with [need-docs] or [FEATURE]

[benoitdm-oslandia]

@DelazJ I am not able to edit the description as asked the in the comment. Here are my suggestions of change for the Elevation profile tool:

11.3.1. The interface

Sets how far from the actual profile line a point can reside within to be included in the results. Uses the map units and is ignored by other layer or geometry types.

==> Sets how far from the actual profile line a pointfeature (point, line, polygon, etc.) can reside within to be included in the results. Uses the map units and is ignored by other layer or geometry types.

11.3.2. Creating an elevation profile

Under options Options drop-down menu, you can set the Tolerance value. This value is used to create a flat buffer around the elevation profile line, visible in the main map canvas. Any visible point feature overlapping that buffer will be captured in the plot canvas.

==> Under options Options drop-down menu, you can set the Tolerance value. This value is used to create a flat buffer around the elevation profile line, visible in the main map canvas. Any visible point feature (point, line, polygon, etc.) overlapping that buffer will be captured in the plot canvas.

11.3.4 Limitations NEW

11.3.4.1 Line and polygon extrusion NEW

In the Elevation properties tab of a layer, it is possible to activate the extrusion. This works fine for points or lines in any case. But, when tolerance is enable and for 3D lines or 3D polygons, extrusion is not trivial because it is equivalent to represent a 3D object (the 3D polygon is re-projected into a 2D polygon in the elevation profile view but with the extrusion dimension). Thus right now the polygon extrusion is disabled when tolerance is enabled.