User:MarkS/Remapping

From OpenStreetMap Wiki
Jump to: navigation, search

This page contains some information on what might be removed come 1 April.

The CSV files contain a list of the object IDs, names and their licence state. The licence state should replicated what is shown in JOSM; thus 'Data Loss' indicates something expected to be removed come 1 April; whilst 'Possible Data Loss' indicates something expected to revert to an earlier state.

Since 11 March the numbers allow for "odbl=clean".

Warning: The numbers given below are for guidance but can't be taken as definitive. For example they don't take account of items changing from one type to another (eg. a tainted secondary road being changed to a trunk road will not show up as trainted trunk road), and quick history sometimes seems to rate things as ok when they show up (legitimately) in badmap.

UK Roads (18 March 2012: 2pm)

This is based on an original extract by Simon Poole which I've then updated using the quick history service to see how many can still be expected to be deleted.

primary 399
primary_link 14
trunk 128
trunk_link 15
total 556

A complete list is also available as a CSV file.

Motorway Junction Nodes (13 March 2012: PM)

This is a list of unique nodes at the start/end of ways tagged with highway=motorway. This therefore represents places where gaps will potential open in the motorway network because the node that joins the motorway to rest of the network is removed from the database.

Data Loss 14
Possible Data Loss 13

For comparison, based on my calculations, there are a total of 10,438 unique nodes at the start/end of motorway ways in the UK.

A complete list is also available as a CSV file.

London Tube Stations (8 March 2012)

Data Loss 50
Possible Data Loss 50

In other words 50 stations will disappear from the map, whilst 50 will change in some way.

A complete list is also available as a CSV file.

How the lists are created

The original UK main roads list was kindly provided by Simon Poole.

The tube station list was generated from an up to date extract of the UK. This extract was converted to o5m format using OSMConvert. A list of all tube stations was then generated using OSMFilter.

The motorway nodes list was generated from an up to date extract of the UK. This extract was converted to o5m format using OMSConvert. The motorway network was then extract using OSMFilter. (These steps give a more manageable file size for the next steps). XSL was then used to produce a list of all the nodes at the start and end of the ways. This list was then processed by an awk script to remove duplicates.

The lists above are then placed into Excel. When the lists need to be updated a VBA macro is used which first queries the overpass api to see if the the object still exists in the database (or has an "obdl=clean" tag). The quick history service is then queried to get the current licence state.

It would be possible to generate other lists. Although please note that as the initial list of objects to watch has to go through overpass and the quick history service then this initial list should not be too large. If your initial list is likely to be large (eg. all UK roads !) you may need to ask Simon Poole to generate the initial list of bad objects before using my method.

Using the figures

The CSV files give a list of the objects and their IDs. Once possible way to use these is to load the CSV file into Excel, copy the column of IDs into a text editor, replace the line breaks with a copy, then using JOSM's Object Download functionality to download the problem cases.