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This repository is now archived. All the stuff in here went to osmium-surplus.

OSM Data Anomaly Detection

Various programs to detect anomalies in OSM data. Many, but not all, of these are errors that should be fixed.

These are all highly efficient C++ programs that can run through a full planet PBF file in a few minutes.

Prerequisites

You need a C++11 compliant compiler. GCC 4.8 and later as well as clang 3.6 and later are known to work. It also works on modern Visual Studio C++ compilers.

You also need the following libraries:

Libosmium (>= 2.11.0)
    https://osmcode.org/libosmium
    Debian/Ubuntu: libosmium2-dev

Protozero (>= 1.4.5)
    This is included in the libosmium repository and might or might not
    have been installed with it. See the libosmium README.
    https://github.com/mapbox/protozero
    Debian/Ubuntu: protozero
    Fedora: protozero-devel

bz2lib
    http://www.bzip.org/
    Debian/Ubuntu: libbz2-dev
    Fedora: bzip2-devel
    CentOS: bzip2-devel

zlib
    https://www.zlib.net/
    Debian/Ubuntu: zlib1g-dev
    openSUSE: zlib-devel
    Fedora: zlib-devel
    CentOS: zlib-devel

Expat
    http://expat.sourceforge.net/
    Debian/Ubuntu: libexpat1-dev
    openSUSE: libexpat-devel
    Fedora: expat-devel
    CentOS: expat-devel

cmake
    https://cmake.org/
    Debian/Ubuntu: cmake
    openSUSE: cmake
    Fedora: cmake

GDAL/OGR
    https://gdal.org/
    Debian/Ubuntu: libgdal-dev

Compiling

A standard CMake setup is used. You can compile like this:

mkdir build
cd build
cmake ..
make

Running

All commands take two arguments, the first is the input OSM data file, the second a directory name where all the output should go. The directory must exist.

Commands have some options, call with --help to see all options. Common options are:

-a, --min-age=DAYS      Only include objects at least DAYS days old
-b, --before=TIMESTAMP  Only include objects changed last before
                        this time (format: yyyy-mm-ddThh:mm:ssZ)
-h, --help              Print help message
-q, --quiet             Work quietly

You can not use --min-age/-a and --before/-b together.

You can run all commands using the same output directory, they are all using distinct output file names.

Results

All programs create

  • one or more OSM PBF files with the data of the different anomalies they detected,
  • an Sqlite file called stats-*.db with statistical data, and
  • a Spatialite file called geoms-*.db containing geometries of the data detected (only for some commands).

You can use the script scripts/collect-stats.sh to collect the stats from the various commands into one database called stats.db. All stats contain a timestamp, so you can aggregate stats from, say, daily runs into one large database.

The timestamp on the stats is the last timestamp of any object in the input file. This may differ slightly between the various commands, because not all commands read all object types.

Commands

odad-find-colocated-nodes

"Colocated nodes" are nodes that have the exact same location. In OSM that is usually an error, but it doesn't have to be. There could be two nodes at the same latitude and longitude but in different heights for instance.

This tool will find all colocated nodes and write them to the output.

Note that the program will create 256 temporary files named locations_xx.dat in the output directory and later remove them. If the program is interrupted those temporary files might be left around.

The program will need between 1 and 2 GByte RAM for caches.

odad-find-orphans

"Orphans" are OSM objects (nodes, ways, or relations) that have no tags and that are not referenced by any other objects. "No tags" in this case also means objects that have only source or created_by tags, because they don't say anything about what an object actually is. Orphan objects are always an error, but, for ways and relations, their members might tell you something about their intended use.

Do not trust the output of this command when run on an extract! The extract might not contain all objects referencing the objects in the extract.

odad-find-unusual-tags

Find "unusual" tags such as empty, very short or long keys, the key "role", or tag "type=multipolygon" on a node or way.

odad-find-way-problems

Finds several problems with way geometries:

  • Way has no nodes (no-node).
  • Way has only a single node (single-node).
  • Way has more than one node, but all nodes are the same (same-node).
  • Way has two or more references to the same node one right after the other (duplicate-node).
  • Way intersects itself at a place where there is no node (self-intersection).
  • Way contains a "spike", a segment from node A to node B and, directly after that a segment back from node B to node A (spike).
  • Way contains a duplicate segment, so a connection between two nodes is in the way more than once (regardless of the direction of that segment) (duplicate-segment).

This command needs as input an OSM file with node locations on ways. See the osmium add-locations-to-ways command on how to create this.

odad-find-relation-problems

Finds several problems with relations.

This command needs as input an OSM file with node locations on ways. See the osmium add-locations-to-ways command on how to create this.

odad-find-multipolygon-problems

Finds several problems with multipolygons without actually building them.

This command needs as input an OSM file with node locations on ways. See the osmium add-locations-to-ways command on how to create this.

License

Copyright (C) 2019-2022 Jochen Topf (jochen@topf.org)

This program is available under the GNU GENERAL PUBLIC LICENSE Version 3. See the file LICENSE.txt for the complete text of the license.

Author

Jochen Topf (https://jochentopf.com/)