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Imposm is an importer for OpenStreetMap data. It reads XML and PBF files and can import the data into PostgreSQL/PostGIS databases.

It is designed to create databases that are optimized for rendering/WMS services.

It is developed and supported by Omniscale, runs on Linux or Mac OS X and is released as open source under the Apache Software License 2.0.


Custom database schemas
It creates tables for different data types. This allows easier styling and better performance for rendering in WMS or tile services.
Multiple CPU/core support
Imposm is parallel from the ground up. It distributes parsing and processing to multiple CPUs/cores.
Unify values
For example, the boolean values 1, on, true and yes all become TRUE.
Localized names
Look for localized names in a configurable order (e.g. name:de, name:en, int_name, name).
Filter by tags and values
It only imports data you are going to render/use.
Efficient nodes cache
It is necessary to store all nodes to build ways and relations. Imposm uses a file-based key-value database (Tokyo Cabinet) to cache this data. This reduces the memory usage.
Generalized tables
It can automatically create tables with lower spatial resolutions, perfect for rendering large road networks in low resolutions for example.
Union views
It can create views that combine multiple tables.
Limit to polygons
It can limit imported geometries to polygons from Shapefiles or GeoJSON.


It does not support differential updates (aka minutely database) at the moment.

It only supports PostGIS databases, but the code is quite modular (only a single file contains PostGIS dependent code) and support for SpatialLite, Oracle, etc. can be implemented.

It is quite efficient with memory. You can import 1 GB .osm.bz2 (~Germany) on a system with 2 GB RAM and Europe (~5 GB PBF) works fine on a system with 8 GB RAM. Larger imports (planet.osm) are still possible but will take longer if you don’t have 16 GB or more (about 20h with 8GB).

There is room for improvements for all of these limitations. Let us know if you want to help out (either with code, or with funding).


There is a mailing list at Google Groups for all questions. You can subscribe by sending an email to:

For commercial support contact Omniscale.


The source code is available at:

You can report any issues at: