Madagascar | Data Improvements

[marjanvandekauter-tomtom]

Project description

Goal

To improve the map quality in Madagascar, we propose to make data improvements by sharing challenges, and when appropriate, fixing data errors, and adding or editing certain kinds of geometry.

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.

Challenges

Quality check challenges

Click to expand.

• Not connected highway

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.

• Tag area=yes on object without feature type

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.

• Impossible angle in a highway

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.

• Invalid Mini-Roundabout

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.

• Polygon has self-intersection

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

• This multipolygon is a simple 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.

• Spiky buildings

Buildings with extremely sharp angles will be identified and corrected if needed.

• Polygon is not closed

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.

Geometry challenges

Click to expand.

• Missing Roads (regional challenge for Eastern Africa)

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.

Geographical scope

Data improvements will be made across the whole country.

Announcements

This project was announced in the Talk-africa mailing list:

• quality check announcement,
• geometry announcement.
• Telegram OSM Africa, and WhatsApp group of Africa, 3rd March 2023.

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

• Maxar Premium Imagery
• Esri World Imagery
• Bing Maps Aerial

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:

• send a message to the project lead Hajar El Ouafi,
• join the conversation in the Talk-africa mailing list, and Telegram OSM Africa (see Announcements),
• email osm@tomtom.com.

[ghost]

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