Rasterize point functionality

[mvmaltitz]

[timlinux]

@ClaraIV could you confirm this behaviour? How would it affect the mockups you shared where indicators each use multiple input files?

[timlinux]

Detailed workflow description:

A python class that uses the areaiterator to process the areas one by one. If should using QGIS processing algorithms as first preference to carry out steps, otherwise do the analysis from first principles without relying on any external libs that are not already shipped with QGIS.

The algorithm should work as follows:

Input 1: A linear network layer (QgsVectorLayer) such as roads or paths
Input 2: A point layer representing pedestrian crossings (QgsVectorLayer)
Input 3: A polygon layer containing grid cells of a specific dimension e.g. 100m x 100m (QgsVectorLayer)
Input 4: Working directory for intermediate outputs

Algorithm steps:

Step 1: Create and interator over the areas and bboxes (current_area, current_bbox)
Step 2: Select all of the lines that intersect with the current_area and store them in a temporary layer (area_lines).
Step 3: Select all of the points that intersect with the current_area and store them in a temporary layer (area_points). This grid layer should have one attribute 'value'.
Step 4: Select all of the grid cells that intersect either a road or a point from area_lines and area_points and store them in a temporary layer (area_grid)
Step 5: Assignment of values to the grid cells:

Assign a value of 3 to a cell if it only intersects with one feature.
Assign a value of 5 to a cell if it intersects with more than one feature.

Step 6: Rasterize the grid using values of the grid cells for the raster. The raster extents should be exactly the same as the iterator area_grid and its CRS.

Step 7: Convert the resulting raster to byte format with lossless compression to minimise the space it requires, removing the prior float32 product.

Step 8: After completing the iteration combine the resulting byte outputs to a raster VRT stored in the working directory.

[timlinux]

Discussing with @osundwajeff and his experience working on the last geest version, the points get processed for one subfactor and the paths for a second.

[mvmaltitz]

Below is what the previous plugin looked like for Active Transport. Only the crosswalks (point) are relevant for this ticket: