# Importing the Database The following instructions explain how to create a Nominatim database from an OSM planet file. It is assumed that you have already successfully installed the Nominatim software itself and the `nominatim` tool can be found in your `PATH`. If this is not the case, return to the [installation page](Installation.md). ## Creating the project directory Before you start the import, you should create a project directory for your new database installation. This directory receives all data that is related to a single Nominatim setup: configuration, extra data, etc. Create a project directory apart from the Nominatim software and change into the directory: ``` mkdir ~/nominatim-planet cd ~/nominatim-planet ``` In the following, we refer to the project directory as `$PROJECT_DIR`. To be able to copy&paste instructions, you can export the appropriate variable: ``` export PROJECT_DIR=~/nominatim-planet ``` The Nominatim tool assumes per default that the current working directory is the project directory but you may explicitly state a different directory using the `--project-dir` parameter. The following instructions assume that you run all commands from the project directory. !!! tip "Migration Tip" Nominatim used to be run directly from the build directory until version 3.6. Essentially, the build directory functioned as the project directory for the database installation. This setup still works and can be useful for development purposes. It is not recommended anymore for production setups. Create a project directory that is separate from the Nominatim software. ### Configuration setup in `.env` The Nominatim server can be customized via an `.env` configuration file in the project directory. This is a file in [dotenv](https://github.com/theskumar/python-dotenv) format which looks the same as variable settings in a standard shell environment. You can also set the same configuration via environment variables. All settings have a `NOMINATIM_` prefix to avoid conflicts with other environment variables. There are lots of configuration settings you can tweak. A full reference can be found in the chapter [Configuration Settings](../customize/Settings.md). Most should have a sensible default. #### Flatnode files If you plan to import a large dataset (e.g. Europe, North America, planet), you should also enable flatnode storage of node locations. With this setting enabled, node coordinates are stored in a simple file instead of the database. This will save you import time and disk storage. Add to your `.env`: NOMINATIM_FLATNODE_FILE="/path/to/flatnode.file" Replace the second part with a suitable path on your system and make sure the directory exists. There should be at least 75GB of free space. ## Downloading additional data ### Wikipedia/Wikidata rankings Wikipedia can be used as an optional auxiliary data source to help indicate the importance of OSM features. Nominatim will work without this information but it will improve the quality of the results if this is installed. This data is available as a binary download. Put it into your project directory: cd $PROJECT_DIR wget https://www.nominatim.org/data/wikimedia-importance.sql.gz The file is about 400MB and adds around 4GB to the Nominatim database. !!! tip If you forgot to download the wikipedia rankings, you can also add importances after the import. Download the files, then run `nominatim refresh --wiki-data --importance`. Updating importances for a planet can take a couple of hours. ### External postcodes Nominatim can use postcodes from an external source to improve searching with postcodes. We provide precomputed postcodes sets for the US (using TIGER data) and the UK (using the [CodePoint OpenData set](https://osdatahub.os.uk/downloads/open/CodePointOpen). This data can be optionally downloaded into the project directory: cd $PROJECT_DIR wget https://www.nominatim.org/data/gb_postcodes.csv.gz wget https://www.nominatim.org/data/us_postcodes.csv.gz You can also add your own custom postcode sources, see [Customization of postcodes](../customize/Postcodes.md). ## Choosing the data to import In its default setup Nominatim is configured to import the full OSM data set for the entire planet. Such a setup requires a powerful machine with at least 64GB of RAM and around 900GB of SSD hard disks. Depending on your use case there are various ways to reduce the amount of data imported. This section discusses these methods. They can also be combined. ### Using an extract If you only need geocoding for a smaller region, then precomputed OSM extracts are a good way to reduce the database size and import time. [Geofabrik](https://download.geofabrik.de) offers extracts for most countries. They even have daily updates which can be used with the update process described [in the next section](Update.md). There are also [other providers for extracts](https://wiki.openstreetmap.org/wiki/Planet.osm#Downloading). Please be aware that some extracts are not cut exactly along the country boundaries. As a result some parts of the boundary may be missing which means that Nominatim cannot compute the areas for some administrative areas. ### Dropping Data Required for Dynamic Updates About half of the data in Nominatim's database is not really used for serving the API. It is only there to allow the data to be updated from the latest changes from OSM. For many uses these dynamic updates are not really required. If you don't plan to apply updates, you can run the import with the `--no-updates` parameter. This will drop the dynamic part of the database as soon as it is not required anymore. You can also drop the dynamic part later using the following command: ``` nominatim freeze ``` Note that you still need to provide for sufficient disk space for the initial import. So this option is particularly interesting if you plan to transfer the database or reuse the space later. !!! warning The datastructure for updates are also required when adding additional data after the import, for example [TIGER housenumber data](../customize/Tiger.md). If you plan to use those, you must not use the `--no-updates` parameter. Do a normal import, add the external data and once you are done with everything run `nominatim freeze`. ### Reverse-only Imports If you only want to use the Nominatim database for reverse lookups or if you plan to use the installation only for exports to a [photon](https://photon.komoot.io/) database, then you can set up a database without search indexes. Add `--reverse-only` to your setup command above. This saves about 5% of disk space. ### Filtering Imported Data Nominatim normally sets up a full search database containing administrative boundaries, places, streets, addresses and POI data. There are also other import styles available which only read selected data: * **admin** Only import administrative boundaries and places. * **street** Like the admin style but also adds streets. * **address** Import all data necessary to compute addresses down to house number level. * **full** Default style that also includes points of interest. * **extratags** Like the full style but also adds most of the OSM tags into the extratags column. The style can be changed with the configuration `NOMINATIM_IMPORT_STYLE`. To give you an idea of the impact of using the different styles, the table below gives rough estimates of the final database size after import of a 2020 planet and after using the `--drop` option. It also shows the time needed for the import on a machine with 64GB RAM, 4 CPUS and NVME disks. Note that the given sizes are just an estimate meant for comparison of style requirements. Your planet import is likely to be larger as the OSM data grows with time. style | Import time | DB size | after drop ----------|--------------|------------|------------ admin | 4h | 215 GB | 20 GB street | 22h | 440 GB | 185 GB address | 36h | 545 GB | 260 GB full | 54h | 640 GB | 330 GB extratags | 54h | 650 GB | 340 GB You can also customize the styles further. A [description of the style format](../customize/Import-Styles.md) can be found in the customization guide. ## Initial import of the data !!! danger "Important" First try the import with a small extract, for example from [Geofabrik](https://download.geofabrik.de). Download the data to import. Then issue the following command from the **project directory** to start the import: ```sh nominatim import --osm-file 2>&1 | tee setup.log ``` The **project directory** is the one that you have set up at the beginning. See [creating the project directory](#creating-the-project-directory). ### Notes on full planet imports Even on a perfectly configured machine the import of a full planet takes around 2 days. Once you see messages with `Rank .. ETA` appear, the indexing process has started. This part takes the most time. There are 30 ranks to process. Rank 26 and 30 are the most complex. They take each about a third of the total import time. If you have not reached rank 26 after two days of import, it is worth revisiting your system configuration as it may not be optimal for the import. ### Notes on memory usage In the first step of the import Nominatim uses [osm2pgsql](https://osm2pgsql.org) to load the OSM data into the PostgreSQL database. This step is very demanding in terms of RAM usage. osm2pgsql and PostgreSQL are running in parallel at this point. PostgreSQL blocks at least the part of RAM that has been configured with the `shared_buffers` parameter during [PostgreSQL tuning](Installation.md#postgresql-tuning) and needs some memory on top of that. osm2pgsql needs at least 2GB of RAM for its internal data structures, potentially more when it has to process very large relations. In addition it needs to maintain a cache for node locations. The size of this cache can be configured with the parameter `--osm2pgsql-cache`. When importing with a flatnode file, it is best to disable the node cache completely and leave the memory for the flatnode file. Nominatim will do this by default, so you do not need to configure anything in this case. For imports without a flatnode file, set `--osm2pgsql-cache` approximately to the size of the OSM pbf file you are importing. The size needs to be given in MB. Make sure you leave enough RAM for PostgreSQL and osm2pgsql as mentioned above. If the system starts swapping or you are getting out-of-memory errors, reduce the cache size or even consider using a flatnode file. ### Testing the installation Run this script to verify that all required tables and indices got created successfully. ```sh nominatim admin --check-database ``` Now you can try out your installation by running: ```sh nominatim serve ``` This runs a small test server normally used for development. You can use it to verify that your installation is working. Go to `http://localhost:8088/status.php` and you should see the message `OK`. You can also run a search query, e.g. `http://localhost:8088/search.php?q=Berlin`. Note that search query is not supported for reverse-only imports. You can run a reverse query, e.g. `http://localhost:8088/reverse.php?lat=27.1750090510034&lon=78.04209025`. To run Nominatim via webservers like Apache or nginx, please read the [Deployment chapter](Deployment.md). ## Adding search through category phrases If you want to be able to search for places by their type through [special phrases](https://wiki.openstreetmap.org/wiki/Nominatim/Special_Phrases) you also need to import these key phrases like this: ```sh nominatim special-phrases --import-from-wiki ``` Note that this command downloads the phrases from the wiki link above. You need internet access for the step. You can also import special phrases from a csv file, for more information please see the [Customization part](../customize/Special-Phrases.md).