Getting the width of a street section from a PML file

[vvoovv]

I'd like to define widths of street sections and other attributes in a PML file.

A PML style is chosen based on the category of an OSM way, the number of lanes, etc.

If possible, an instance of the class StreetSection should be created earlier in the code. A renderer exposes a method getStyle which accepts tags as a parameter and returns a style defined in PML. The attributes of the instance of the class StreetSection (width, the number lanes) are set in accordance with the values in the PML style.

How easy would it be to refactor the existing code?

[polarkernel]

How easy would it be to refactor the existing code?

I don't think this is too complicated. The instances of StreetSection are constructed at the end of the StreetGenerator processes. Before that, an internal and complicated class WaySection, defined in way/way_section.py is used. Its constructor creates it from the section network in the StreetGenerator's createWaySections() function. This is also where the way widths are set, based on the wayCategoryProps in way_properties.py, by calling estimateWayWidths(). The lane patterns for the turn lanes are also set here.

In createWaySections(), the method getStyle could be called, and their returned parameters could replace the default ones in WaySection.

[vvoovv]

What is the difference between the classes NetSection, WaySection and StreetSection?

[polarkernel]

What is the difference between the classes NetSection, WaySection and StreetSection?

Well, the NetSection class holds the edges in the instances (networkGraph, sectionNetwork) of the WayNetwork class. It is only related to the networks.

The WaySection class is the working horse of way processing. Unlike the instances of NetSection, there is only one (directed) instance per way section. Its polyline is represented by an instance of the PolyLine class, which provides powerful methods for parametrization, the calculation of intersections, trimming, distances, projections, offset lines, and so on. WaySection is also used to keep track of lanes and their widths.

Finally, the class StreetSection (formerly TrimmedWaySection) is used as the output class. Classes internal to street generation (for instance PolyLine) are omitted, so that only Python classes or Blender classes are used there.

[vvoovv]

What would be the obstacles to merge WaySection and StreetSection into a single class?

[polarkernel]

What would be the obstacles to merge WaySection and StreetSection into a single class?

The main differences I see are

• Not all sections in the WaySections dictionary are valid. Some have been invalidated because they were too short or were covered by clusters or for other reasons. If we used WaySections instead of StreetSections, the renderer would have to test for isValid on each instance.
• The polyline of the WaySection keeps the original length of the section as given by the OSM data. The shorter trimmed centerline, e.g. truncated by intersections, must be calculated and stored anyway.
• The keys of the WaySection dictionary are different from the keys of the _StreetSection_s dictionary, but I can't say yet if this would be a problem.
• The lane data in StreetSections is different in details from that in WaySections. StreetSections would require its own attributes.

[vvoovv]

I suggest gradually merging WaySection and StreetSection. But first I'd like to integrate reading PML attributes in the method createWaySections() of the class StreetGenerator.

[polarkernel]

I suggest gradually merging WaySection and StreetSection.

OK. Just out of curiosity: What's the benefit of that?

[vvoovv]

OK. Just out of curiosity: What's the benefit of that?

No need to create an additional structure.