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Programming Guide

Building from source#

OSM Express uses CMake for its build scripts. It's only been tested with the Clang C++ compiler so far.

Most dependencies are included as Git submodules in the vendor/ directory, but a few stable, common libraries are expected to exist on your system, including bzip2, zlib, Expat and OpenSSL.

FreeBSD 12#

sudo pkg install cmake expat

macOS#

via Homebrew: brew install cmake bzip2 zlib openssl expat

Additional macOS notes: the Clang compiler should be available via XCode Command Line Tools.

Ubuntu 18.04#

via Apt package manager: sudo apt install cmake clang libbz2-dev libz-dev libexpat-dev libssl-dev

Build Instructions#

git clone --recursive https://github.com/protomaps/OSMExpress.gitcd OSMExpresscmake -DCMAKE_BUILD_TYPE=Release .make

macOS note: If OpenSSL is installed through Homebrew, you may need to add an option to your cmake command: -DOPENSSL_INCLUDE_DIR=/usr/local/Cellar/openssl/1.0.2s/include/

Using the C++ Headers#

Example: Way ID to WKT#

See examples/way_wkt.cpp for a commented program.

Example: Bbox to Way WKTs#

See examples/way_wkt.cpp for a commented program.

Python#

Install the library with pip install osmx . This will also download and install the pycapnp and lmdb Python libraries.

The Python API supports only location, node, way and relation lookups at the moment. Example:

import osmx
env  = osmx.Environment('planet.osmx')txn = osmx.Transaction(env)locations = osmx.Locations(txn)nodes = osmx.Nodes(txn)ways = osmx.Ways(txn)
way = ways.get(123456)
for node_id in way.nodes:    print(locations.get(node_id))
print(osmx.tag_dict(way.tags))