faq.html

---
layout: default
title: Frequently Asked Questions (FAQ)
---

<p>&uarr; <a href="docs.html">Documentation</a></p>

<div class="desc">
    <img src="/img/faq-128x128.png" width="64" height="64" alt=""/>
    <h1>Frequently Asked Questions</h1>
    <p>...and their answers</p>
</div>

<p><b>Sections:</b>
<a href="#building">Building</a> &middot;
<a href="#features">Features</a> &middot;
<a href="#upgrading">Upgrading</a> &middot;
<a href="#misc">Miscellaneous</a>
</p>

<h2 id="building">▶ Building</h2>

<h3>Which operating systems are supported?</h3>

<p>Libosmium and other related software on this site is developed on Linux
and works well there. With tiny exceptions everything also works on macOS
out of the box. Most software also works on Windows. A CMake configuration
which should work on all operating systems is supplied for all projects.</p>

<h3>I can't find out how to build the Osmium Library?</h3>

<p>The C++ Osmium Library is a header-only library. You dont' have to build
it. Just install the header files and include them as needed from your code.</p>

<h3>Which build system is used?</h3>

<p>We are using <a href="https://cmake.org/">CMake</a>.</p>


<h2 id="features">▶ Features</h2>

<h3>Can Osmium work with OSM history files? Change files? Changesets?</h3>

<p>Yes. They are all supported. See the <a
href="/libosmium/manual.html">manual</a> for details.</p>

<h3>Can Osmium do Coordinate Transformations?</h3>

<p>Yes. Osmium has builtin support for the OSM native format WGS84 (EPSG 4326)
and Web Mercator (EPSG 3857). It can also use the <a
href="https://proj4.org/">PROJ.4</a> library to transform to about any
coordinate reference system out there.</p>


<h2 id="upgrading">▶ Upgrading</h2>

<h3>What is the difference between "old" and "new" Osmium?</h3>

<p>The "old" Osmium was developed from 2010 to 2013. With the experience
gained and with the new possibilities of C++11 we started on the "new"
Osmium in 2013, a more or less complete rewrite of the C++ Osmium Library.
Today the "new" Osmium Library has all the functionality of the old one plus
a lot more.</p>

<p>The old Osmium is still available from <a
href="https://github.com/joto/osmium">github.com/joto/osmium</a>, but it is in
maintainance mode, ie no new functionality will be added.</p>

<p>Unless you don't have a C++11 capable compiler, we recommend using
the "new" osmium available from this web site.</p>


<h3>Where is "osmjs"?</h3>

<p>The "old" Osmium had a command line program called "osmjs" that allowed you
to use the functionality of the Osmium C++ library from Javascript. This has
been superseeded by the <a href="/node-osmium/">Node Osmium</a> NodeJS module.
The NodeJS module allows you to use thousands of existing NodeJS modules out
there in your program making this approach much more flexible.</p>

<h2 id="misc">▶ Miscellaneous</h2>

<h3>Wait, I am confused! Is Osmium a library or a program or what?</h3>

<p>The core is a <a class="ext"
href="https://en.wikipedia.org/wiki/Header-only">C++ header-only library</a>
called "<a href="/libosmium/">Osmium Library</a>" or "libosmium", but sometimes
just called "Osmium". Built on top of that are many programs with their own
names, one is the command line multipurpose "<a href="/osmium-tool/">Osmium
Tool</a>" or short "Osmium". In addition there are bindings of the C++ library
for Javascript ("<a href="/node-osmium/">Node Osmium</a>") and Python ("<a
href="/pyosmium/">PyOsmium</a>").</p>

<p>The <a class="ext" href="https://github.com/joto/osmium">old version</a> of
the Osmium Library was also just called "Osmium".</p>

<h3>I don't want to program in C++. Can I use Osmium from other languages?</h3>

<p>Yes. There is the <a href="/pyosmium/">PyOsmium</a> Python module (written
by Sarah Hoffmann). There is also a now unsupported <a
href="/node-osmium/">Node Osmium</a> NodeJS module for Javascript developers
(written by Dane Springmeyer and Jochen Topf). Not all functionality available 
from C++ is available through those modules and you'll take a performance hit, 
but they are much easier to use for the average programmer.</p>

<p>If you are interested in making Osmium available in other languages, come
<a href="/contact.html">talk to us</a>.</p>