Tag: Analyse

Detecting vandalism in OpenStreetMap – A case study

This blog post is a summary of my talk at the FOSSGIS & OpenStreetMap conference 2017 (german slides). I guess some of the content might be feasible for a research article, however, here we go:

Vandalism is (still) an omnipresent issue for any kind of open data project. Over the past few years the OpenStreetMap (OSM) project data has been implemented in a number of applications. In my opinion, this is one of the most important reasons why we have to bring our quality assurance to the next level. Do we really have a vandalism issue after all? Yes, we do. But first we should take a closer look at the different vandalism types.

It is important to distinguish between different vandalism types. Not each and every unusual map edit should be considered as vandalism. Based on the OSM wiki page, I created the following breakdown. Generally speaking, vandalism can occur intentionally and unintentionally. Therefore we should distinguish between vandalism and bad-map-editing-behavior. Oftentimes new contributors make mistakes which are not vandalism because they do not have the expert mapper knowledge. In my opinion, only intentional map edits such as mass-deletions or “graffiti” are real cases of vandalism.

A comparative study between different OpenStreetMap contributor groups – Outline 2016

Over the past few years I have written several blog posts about the (non-) activity of newly registered OpenStreetMap (OSM) members (2015, 2014, 2013). Similarly to the previous posts, the following image shows the gap between the number of registered and the number of active OSM members. Although the project still shows millions of new registrations, “only” several hundred thousand of these registrants actually edited at least one object. Simon showed similar results in his yearly changeset studies.


The following image shows, that the project still has some loyal contributors. More specifically, it shows the increase in monthly active members over the past few years and their consistent data contributions based on the first and latest changeset:


However, this time I would like to combine the current study with some additional research. I tried to identify three different OSM contributor groups, based on the hashtag in a contributor’s comment or the utilized editor, for the following analysis:

What Impact has the OSM License Change in Germany on the Street Network Length? – 1st Attempt –

The OpenStreetMap project will possibly finalize its license change on April 1st 2012. There are certain concerns in the community about possible data losses and to keep them as little as possible, several remapping activities have been started. A really nice overview of “Remapping principles” and “Tools to help you” can be found here.

Frederik’s OSMInspector (OSMI) and Simon’s CLEANMAP are two very handy remapping tools. Both display data that will likely be removed after April 1st due to the fact that this data was collected by contributors that did not accept the license change. In Germany you will find several areas that are affected by these changes and might even leave some new blank spots in the map. But what impact do these changes have on the total length in kilometers per street category in Germany?

OSM Routing View Worldwide 2011-11

Really great news for all our non-European OpenStreetMap.org Mappers: Since last month, the OSM Routing View is available for the whole world. You can read more in Frederik’s blog post. Yesterday he sent me the latest results of the view and I did some analysis with it. To all new readers: you can find more information about the OSM Inspector (OSMI) here. The Routing View within the OSMI “shows problems in the data, related to routing and navigation” (direct link).

However, here are the new *worldwide* stats for November 2011: we have a total of about 1,3 Mio errors. We can divide them into the following groups:

  • Unconnected 1 meter: 248000
  • Unconnected 2 meter: 62000
  • Unconnected 5 meter: 170000
  • Duplicate (number of duplicate segments): 833000

The following diagram shows the amount of errors per continent:

In the following charts you can see the amount of errors separated by country and the amount of errors in detail per country for “Europe”:

The OpenStreetMap Evolution of Austria (2007-2011)

Currently I am working on a research paper about the OpenStreetMap evolution of Germany. For the last AGIT conference in Salzburg and the upcoming State of the Map Europe (SotM-EU) conference in Vienna I did a similar analysis about the OpenStreetMap Evolution of Austria. You can see the results in the following posters in English and German:

The OpenStreetMap Evolution of Austria (2007–2011)

The OpenStreetMap Evolution of Austria (2007–2011)

Die OpenStreetMap Entwicklung in Österreich (2007–2011)

Die OpenStreetMap Entwicklung in Österreich (2007–2011)

A further nice visualization of the OpenStreetMap data in Austria for the year 2010, can be found in a blog post by Max Kossatz.

A comparison of several routing-engines – Which one is the fastest?

In the past blog post I wrote about the newest changes and encoding techniques that have been implemented in the Open Source Routing Project (OSRM). So I think it is time do a little comparison analysis about the request/response time of several routing APIs. The main question I wanted to answer was: “Is an OpenStreetMap direction service faster than G**gle?” I tested the following direction APIs for cars (fastest): MapQuest, CloudMade, G**gle and finally OSRM. For the analyses I wrote a small Java tool, which measured the time to get a result of a routing-service. I did all tests at home with a “regular” 12kbit/s internet connection. I tested several distance levels and the results can be seen in the following table. It shows the average times of five requests for each route with a delay of 3 seconds between each request/response. Overall I did this analysis three times.

Edit Stats for OSM Japan

Kate created some editing stats for OpenStreetMap Japan last Thursday. You can find her blog post here: “Quick Japan Editing Stats for OpenStreetMap”

During the creation of the layers for the “Road Status in Japan”, I log some editing information of OpenStreetMap too. As I mentioned in my blog post, I use the Geofabrik extracts for Japan (Sendai region only). They have the following bounding box (thx Frederik):

1.412259E+02 3.663895E+01
1.427964E+02 4.038643E+01
1.411296E+02 4.038351E+01
1.394639E+02 3.665750E+01
1.412259E+02 3.663895E+01

And here are several diagrams of the editing in Japan (Sendai region only):

In numbers (March 20th, 2011 12:50):

  • Overall amount of OSM Nodes: 5138123
  • Overall amount of OSM Ways: 149978
  • Overall amount of Highways: 47156
  • Number of Barrier Nodes: 528
  • Impassable Ways: 463
  • Number of Users (Contributors): 308
  • Length of OSM Ways [km]: 29049,71
  • Length of impassable Ways [km]: 222,58

The Return of “Unmapped Places in OSM EU”

My last blog post about “Unmapped Places in Europe” was read by more then 800 people. So I think it’s time to redo the analyses a second time after three months. At the moment (March 11th, 2011) we have (according to the Geofabrik extract) 505091 places in OpenStreetmap Europe. They can be separated into the following place-types:

  • city=1055 (as of Dec. 5th, 2010 it was 1045 -> +1%)
  • town=16106 (as of Dec. 5th, 2010 it was 16032 -> +0.5%)
  • suburb=24913 (as of Dec. 5th, 2010 it was 23563 -> +6%)
  • village=278691 (as of Dec. 5th, 2010 it was 271147 -> +3%)
  • hamlet=184326 (as of Dec. 5th, 2010 it was 165804 -> +11%)

During my last and also during this analysis I *only* used those places that had a corresponding “village”-value. My tool works so far as followed:

  1. Get only places with a village-tag.
  2. Search nearby (ca. 600m distance) for a street with one of the following highway-types: residential, service, living_street, cycleway, footway, pedestrian, steps or platform.

Growing agreement & relicensing OSM -Update-

My last blog post about the growing agreement to the new CTs is now nearly three months ago. Time for a short update: During the aforementioned time frame, about 32 contributors accepted the new CTs every day. Overall this means that since October 21 2010 there are about 43 contributors each day who accepted the new CTs. I updated my diagram with the latest numbers:

In December I conducted an analysis about the “Change of OSM object numbers through relicensing”. This time I only declared the last modifier of an OSM object (node/way/relation) as the owner of the object! The last and the new results can be seen in the following diagrams:

In my OSM-user-database of March 9th, 2011 a total of 120456* members are the “owners” of the following OSM objects (* Notice: Not every member of the OSM project (>350000 members) has contributed!):

  • Number of nodes: 1007604532
  • Number of ways: 85365727
  • Number of relations: 899145

Updated Error Summary for Europe

This month I tried something new. But first we will start with the usual monthly stats of the OSM Inspector Routing for Europe, this time for the middle of February 2011. Overall the following amount of errors appears for “Europe”: Unconnected Roads: ca. 107000 and Duplicate Ways (number of duplicate segments): ca. 109000 (in the OSM Wiki you can find more information about the error-types). This means that altogether there are 2600 unconnected streets and 16900 duplicate way segment errors have been fixed. In total we have an increment of 1111000 new OSM way segments for routing during the past 4 weeks in Europe (01/20/2011: 30600000, 02/20/2011: 31710000).

The following image shows the amount of errors divided by country for today’s Europe OpenStreetMap dataset:

In the past month several other countries were able to reduce the amount of errors, such as in: France (-1600), Italy (-1600), Poland (-1900), Sweden (-2300) and United Kingdom (-8000!!!). So congratulation to the UK, this is your month 🙂