NVDB

From OpenStreetMap

This is a swedish Network Vay DataBase, it's used by the swedish government to measure the quality of roads

Summary from User:LA2/Diary_for_Q1_2006

March 3, 2006: The national Swedish Road Administration, Vägverket, provides a Nationell Vägdatabas (NVDB), which of course is copyrighted and sold for a fee. However, the specification of the data format is available free of charge, NVDB - Specifikation av innehåll - vägnät (PDF), version 4.1.0, April 2004. On 38 pages it describes how roads in the database are represented as "points" (punkter) connected by straight line segments. The points are given in 3 dimensions in the Swedish system RT90, which is based on WGS84. The terminology used is a little special. "Nodes" (noder) are points that mark the end or intersection of longer runs of line segments, called "reference links" (referenslänkar). Reference links have a starting (startnod) and ending node (slutnod), which implies they have a direction. Driving can be allowed in one direction, but not in the other. This is indicated by "attributes" (attribut), associated with reference links. Nodes can also have attributes, such as "possibility to turn around" (at the end of a road). All nodes and reference links have a start (fråndatum) and end date (tilldatum). New roads have an end date of 9999-12-31 (so there will be a Y10K problem). The document describes the various attributes, and quality requirements for the values and the geometry. The description could be used to write a verifier for OSM data. See for example illustration 8 on page 23 that indicates that line segments should be longer than 5 meters.