Monthly Archives: March 2017

OSM first to honour plate tectonics

OpenStreetMap is set to be the first world-wide geo database that actively tracks plate tectonics. The OSM Foundation board has given the green light for tectonic correction to be applied to the OSM database, starting today.

You won’t notice it immediately – the changes are minuscule enough to be laughed at by some. But the effects are undeniable, and our always dedicated sysadmin team has been hard at work to devise queries against our database that correct for plate tectonics.

As you know, the earth’s surface is made of tectonic plates that drift apart slightly over time. With OSM using the WGS84 coordinate reference system (as opposed to e.g. ETRS89 which also has latitudes and longitudes but defines them relative to fixed markers), our coordinates get “out of sync” with time.

Plate motion based on Global Positioning System (GPS) satellite data from NASA JPL. The vectors show direction and magnitude of motion. (Wikimedia Commons)

This movement can amount to up to 10 centimetres per year. Luckily, models exist that tell us just how much the earth is moving at any given location. And of course our data model provides us not only with the latitude and longitude of a point, but also with the time when it was entered. Assuming the data was correct at the time of entering OpenStreetMap, we can compute exactly how much that particular point has moved in the time since it was entered, and we can update the coordinates accordingly. (This is, of course, just half of the story – where aerial imagery has been used to trace data, we rely on correct source tagging to automatically determine the date when the images were taken, to compute the applicable tectonic correction.)

A point that was entered just yesterday won’t move at all; a point entered at the same location 5 years ago may have to be moved by up to 0.5 metres.

In order not to burden our database with needless new version numbers for nearly all node objects, we’ve chosen to simply update the coordinates for all objects in-place; this means that the tectonic correction happens seamlessly, without leaving traces in the object history.

The first corrections will be applied today, and we’ll revisit the issue on the same day in the coming years.

If this all sounds like techno-babble to you – just take away one thing: OSM does everything in their power to achieve maximum data quality and accuracy.

SotM 2018 Call for Venues

The State of the Map working group is delighted to announce that the call for venues for the year 2018 is now open!

State of the Map 2018 – Call for venues

Why so early?

Following on from previous years we are opening the call for venues early. This gives you the greatest flexibility over dates you can pick in 2018. It also makes it easier for others who may be wanting to run OpenStreetMap events – we can assist with calendar planning to help avoid any problematic clashes.

How’s SotM 2017 shaping up?

Planning for State of the Map 2017 in Aizuwakamatsu, Japan is coming along nicely. We are currently reviewing the applications for our scholarship program, whilst the call for proposals closes this Sunday. Keep up to date with all the latest news about event tickets, hotel deals and the final program by signing up to our newsletter.

Contact us

The State of the Map working group is here to help you. This year we have provided a template to help you when it comes to recording details about potential venues and catering services. We encourage you to contact us on team@stateofthemap.org as early as possible so that we can provide guidance if required.

Use of CC BY 4.0 licensed data in OpenStreetMap

CC spotlight photo CC-BY Timothy Vollmer

After careful consideration and consultation with Creative Commons, we have decided to continue our regime of asking for explicit permission for use in OpenStreetMap from licensors of CC BY databases and data.

Although OpenStreetMap is largely created by volunteers that go out and map their neighbourhoods, we have often used external datasets to improve the map, either for cross-checking or more directly integrating the data. Many of these datasets are released on CC BY (Creative Commons Attribution) terms and that makes interoperability between these licences and our distribution licence, the ODbL 1.0, an important consideration for any use of such data in OSM.

Both the 2.0 and 3.0 versions of the CC BY (Creative Commons Attribution) licence have been popular with government and other sources for a long time. Due to differences between CC BY and the ODbL with respect to attribution, the LWG (OSMF Licence/Legal Working Group) has always required explicit permission from licensors to use such data in OpenStreetMap and attribute by adding an entry to our attribution pages on our central websites.

CC BY 4.0 is a revision of the original CC BY license with provisions for handling database rights and simpler language. You can see a summary of differences between the licenses here. The new version is becoming increasingly popular with potential data sources and we have received multiple requests to make a statement on compatibility of CC BY 4.0 licensed databases and data with the ODbL. For these reasons the LWG started, late last year, an effort to review the licence and to provide guidance to our contributors on the suitability of CC BY 4.0 material for OSM.

There had been some hope that CC BY 4.0 sources would be directly compatible with the ODbL. But while neither CC nor the OSMF has undertaken a complete compatibility analysis, we have identified at least one  point of incompatibility and one possible challenge regarding attribution that lead us to our decision to continue to ask for explicit permission to use BY 4.0-licensed material in the OSM project. This is the best path forward.

The reasons for this decision are twofold: CC BY 4.0 allows some more flexibility in how a licensee can attribute the original source and many people have suggested that our indirect attribution mechanism already fulfills the requirements of BY 4.0. However the OSMF believes that licensors of BY 4.0 material may be surprised by this and that we should, for courtesy and good form reasons, continue to ask for explicit permission to attribute via our websites.

The 2nd reason is that the CC BY licences contain a strict prohibition on distributing so licensed material with DRM-enabled media/transport. The ODbL contains a similar restriction, but allows parallel distribution of “Derivative Databases” as a way to fulfill the obligation for unrestricted access. Distribution of ODbL “Produced Works” (for example maps) does not even require that.To avoid this incompatibility we will be requiring an explicit waiver of the prohibition on applying Technological Effective Measures (as defined in the license) found in Section 2a5B of CC  BY 4.0.

To make obtaining the required permissions easier for everybody involved we have prepared a cover letter and a waiver form and a similar document for obtaining the necessary waivers for the 2.0 and 3.0 versions of CC BY. Please do not forget that imports need to follow our Import Guidelines and that having legal permission is just one of the required steps for a successful project using third party data.

I would like to thank Creative Commons, in particular Diane Peters for the support during this process and Kathleen Lu from Mapbox for drafting the cover letters and waiver forms.

Simon Poole – For the OSMF Licence Working Group

 

Planned downtime Sun 12th 11:00

In case you missed the mailing lists announcement from the Operations Working Group, there will be a one hour period of downtime next Sunday (week today) :

We are planning to upgrade the software which runs the main OpenStreetMap database. Unfortunately, we cannot do this without a small amount of downtime. We would like to schedule this at a time which minimises the impact it will have, and plan to conduct the upgrade between 11:00 and 12:00 UTC on the morning of Sunday 12th March.

We expect that the database upgrade will not take the full hour, and we will endeavour to keep the site online for as much of that period as possible, and have it back to normal status as quickly as possible. However, there’s always the chance for things to go wrong, so please plan for the site to be down for the whole period.

The website and editing API will be affected, but other OSM services including the tile server, Nominatim, wiki, help and taginfo should continue to work as normal.

We will keep you updated through the Platform Status wiki page and OSM_Tech twitter account

If you experience any problems with the API after the end of the upgrade, please get in touch with us on the #osm IRC channel, or by email.

Apologies for any disruption this may cause and many thanks in advance for your patience,

Operations Working Group