https://github.com/osmcode/experimental-osm-db

Experimental OSM Database based on Libosmium
https://github.com/osmcode/experimental-osm-db

c-plus-plus openstreetmap

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Experimental OSM Database based on Libosmium

• Host: GitHub
• URL: https://github.com/osmcode/experimental-osm-db
• Owner: osmcode
• License: gpl-3.0
• Created: 2015-04-18T17:07:10.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2021-11-28T13:23:48.000Z (about 3 years ago)
• Last Synced: 2024-07-30T19:45:42.943Z (5 months ago)
• Topics: c-plus-plus, openstreetmap
• Language: C++
• Size: 70.3 KB
• Stars: 0
• Watchers: 6
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# EODB - Experimental OSM Database

Code for an experimental OSM database. The idea is to explore the possibilities

of building some kind of OSM database on top of Libosmium. The database can

be created from a planet file and later updated from change files. It can then

be used to derive other data formats that can be used for rendering etc.

This code is EXPERIMENTAL, it is not intended to be used for anything beyond

trying out different approaches to the problem. It is very preliminary, poorly

documented and will probably not work for you. :-)

## Prerequisites

You'll need Libosmium (http://osmcode.org/libosmium) and its dependencies

installed first.

These programs will only for on 64bit systems.

For some programs you need [leveldb](https://github.com/google/leveldb). On

Debian/Ubuntu that's package `libleveldb-dev`.

## Building

This code uses CMake for its builds. For Unix/Linux systems a simple

Makefile wrapper is provided to make the build even easier.

To build just type `make`. Results will be in the `build` subdirectory.

Or you can go the long route explicitly calling CMake as follows:

    mkdir build

    cd build

    cmake ..

    make

## Running

There are several programs implementing different parts of the "database". Use

`eodb_create` to create a "database" from any OSM data file. Use `eodb_export`

to write (part of) the database into an OSM file. Use `eodb_dump` to dump

indexes and maps to stdout, and use `eodb_lookup` to do index and map lookups.

## Database Format

This code uses a simple database format. Each "database" is a directory with

the following files:

* `data.osr`: OSM data itself in Osmium internal binary format.

* `nodes.sparse.idx`, `ways.sparse.idx`, and `relations.sparse.idx`: Index

  mapping object ID to offset in `data.osr`. Instead of `sparse` it can

  also be called `dense`.

* `node2way.map`: Index mapping node IDs to the IDs of ways that contain those

  nodes.

* `node2relation.map`, `way2relation.map`, and `relation2relation.map`. Index

  mapping member IDs to the IDs of the relations with those members.

* `locations.sparse.idx` or `locations.dense.idx`: Node locations indexed

  by node ID.

## Index Formats

Osmium DB supports two different types of indexes called *dense* and *sparse*.

* The *dense* index is used for large datasets, such as the whole planet or

  continent-sized extracts. The data is stored in a large array and can be

  directly looked up by ID. The size of the index only depends on the largest

  ID used and the size of the value to be looked up.

* The *sparse* index is used for small datasets, such as city- or country-sized

  extracts. The data is stored as pairs of ID and Value ordered by ID. The

  lookup is by binary search. The size depends on the number of IDs used

  and the size of ID and value.

File names in the database directory will reflect the type of index used.

## License

This software is released unter the GPL v3. See LICENSE.txt for details.

## Author

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