South Africa | Data Improvements #71
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marjanvandekauter-tomtom
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quality checks
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Project description
Goal
To improve the map quality in South Africa, we propose to make data improvements by sharing challenges, and when appropriate, fixing data errors, and adding or editing certain kinds of geometry.
When appropriate, our team will also work on these challenges. If a challenge is more suitable to be solved without organized help, we will leave it for local users interested in completing the tasks. Challenges like this will be indicated as such in the overview below.
How to participate
Anyone is welcome to contribute to this project by participating in our MapRoulette challenges. Here is the extended documentation for using MR. Note that sometimes additional instructions are provided within the challenges.
We also strongly encourage you to make use of the resources listed in the OSM wiki section South Africa Wiki page while you are editing.
Challenges
Quality check challenges
Click to expand.
The tag lanes=* on ways with tag highway=* indicates the amount of lanes on the road at hand. The value for the lanes tag should be only one of the following numbers: 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10. Any other value is incorrect and should be fixed.
Ways with tag highway=* must be connected to the rest of the road network to ensure its continuity, e.g. for route planning. When such a way is not connected to another way with tag highway=*, an error is logged.
The area=yes tag is required for some closed ways when used to define a polygon. For closed ways with other tags, there is an assumption that the way defines an area. In some circumstances, a closed way may define both a closed polyline and an area. When tag area=yes is used, it is expected that one of the necessary accompanying tags is also found.
In general, roads intended for vehicles should be built to maintain proper angles which ensure maneuvers and fluent traffic. Extreme, too sharp angles applied to a way may indicate errors in the road geometry.
This check identifies invalid turn restrictions. Invalid turn restrictions occur in a variety of ways, from invalid members to edge geometry issues to not being routable to wrong topology. Relations, ways and nodes in relations as well as turn restrictions are checked. A relation needs to have exactly one way with role 'from' and exactly one way with role 'to'. These ways should be linked together by at least one way with role 'via' OR with exactly one node with role 'via' (no more and no less).
Mini-roundabouts are a special kind of roundabout with the same rules as other roundabouts, but present as painted circles rather than physical circles. There might also be a low, fully traversable dome or island that vehicles can drive across. Road traffic flows in one direction around a point in the middle, and the traffic in the roundabout has right-of-way. A mini-roundabout is recorded using the tag highway=mini_roundabout.
The necessary edits will be made to fix cases where the tag on a way indicates that the object is a polygon feature, but the way does not meet the definition of a closed way because it is self-intersecting, or ways in a relation with the same role form a self-intersecting polygon
Simple areas are mapped in OSM by creating a closed way and tagging it as an area object rather than a line. Relations of the type multipolygon are used to represent complex areas with holes inside or consisting of multiple disjoint areas. A multipolygon relation can have any number of ways in the role outer (the outline) and any number of ways in the role inner (the holes), and these must form valid rings to build a multipolygon. When a relation of the type multipolygon consists of only one member, which is a simple area, an error is logged.
Buildings with extremely sharp angles will be identified and corrected if needed.
Features intended to be a polygon should be correctly tagged. When the tag indicates that the object should be a polygon, but the geometry is built out of a NON-closed way, an error is logged.
Identify and fix if needed, cases where highway junctions are incorrectly or imprecisely mapped.
Geometry challenges
Click to expand.
Leads are generated based on a spatial comparison of highways and buildings available in the OSM data. The objective is to Identify and fix, if needed, cases where a way with tag highway=* intersects with a building.
Data analysis done by TomTom suggests that there should be a road or track here in OSM, but it is missing.
Missing Highway Surface
Click to expand.
Add Surface to Highway
The goal of this challenge is to identify and add missing surface tags on a road network. We queried OSM for ways with certain highway=* values where the surface tag was missing.
Edits based on User Feedback
We will make improvements to OSM based on user feedback submitted for the TomTom map after comparing and ensuring that it is also valid for OSM.
Here is a list of the types of edits to be made, provided they do not conflict with others’ edits and a local source is available:
Highways
Addresses
POIs (Points of Interest)
Land Use
Buildings
Water
Geographical scope
Data improvements will be made across the whole country.
Announcements
This project was announced in the:
TomTom organised editing
We will follow the Organised Editing Guidelines for this project. TomTom will not make any edits until two weeks after the project announcement. Here is our Organised Editing page, including a list of our editors.
How to find TomTom's edits
All edits made by our team have the hashtag #tt or #tomtom.
Sources for editing
For some OSM map edits TomTom editors will use proprietary sources for support. These will typically be in situations where there is not sufficient evidence using the available sources in OSM editors themselves. The proprietary sources will be ground-level imagery and GPS traces, both collected by TomTom's mobile mapping vans. On occasion, we will also use sources collected from a field survey by one of TomTom's sourcing specialists who have visited the location and collected data to support the required map updates.
How to reach out
If you have remarks about a specific edit of ours, please drop a comment in the changeset, and we will do our best to respond thoughtfully. Or, you can also:
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