Provided by: osmium-tool_1.16.0-1build1_amd64 
NAME
osmium-extract - create geographical extracts from an OSM file
SYNOPSIS
osmium extract --config CONFIG-FILE [OPTIONS] OSM-FILE
osmium extract --bbox LEFT,BOTTOM,RIGHT,TOP [OPTIONS] OSM-FILE
osmium extract --polygon POLYGON-FILE [OPTIONS] OSM-FILE
DESCRIPTION
Create geographical extracts from an OSM data file or an OSM history file. The region (geographical
extent) can be given as a bounding box or as a (multi)polygon.
There are three ways of calling this command:
• Specify a config file with the --config/-c option. It can define any number of regions you want to cut
out. See the CONFIG FILE section for details.
• Specify a bounding box to cut out with the --bbox/-b option.
• Specify a (multi)polygon to cut out with the --polygon/-p option.
The input file is assumed to be ordered in the usual order: nodes first, then ways, then relations.
If the --with-history/-H option is used, the command will work correctly for history files. This
currently works for the complete_ways strategy only. The simple or smart strategies do not work with
history files. A history extract will contain every version of all objects with at least one version in
the region. Generating a history extract is somewhat slower than a normal data extract.
Osmium will make sure that all nodes on the vertices of the boundary of the region will be in the
extract, but nodes that happen to be directly on the boundary, but between those vertices, might end up
in the extract or not. In almost all cases this will be good enough, but if you want to make really sure
you got everything, use a small buffer around your region.
By default no bounds will be set in the header of the output file. Use the --set-bounds option if you
need this.
Note that osmium extract will never clip any OSM objects, ie. it will not remove node references outside
the region from ways or unused relation members from relations. This means you might get objects that
are not reference-complete. It has the advantage that you can use osmium merge to merge several extracts
without problems.
OPTIONS
-b, --bbox=LONG1,LAT1,LONG2,LAT2
Set the bounding box to cut out. Can not be used with --polygon/-p, --config/-c, or
--directory/-d. The coordinates LONG1,LAT1 are from one arbitrary corner, the coordinates
LONG2,LAT2 are from the opposite corner.
-c, --config=FILE
Set the name of the config file. Can not be used with the --bbox/-b or --polygon/-p option. If
this is set, the --output/-o and --output-format/-f options are ignored, because they are set in
the config file.
--clean=ATTR
Clean the attribute (version, timestamp, changeset, uid, user), from the data before writing it
out again. The attribute will be set to 0 (the user will be set to the empty string). This
option can be given multiple times. Depending on the output format these attributes might show up
as 0 or not show up at all.
-d, --directory=DIRECTORY
Output directory. Output file names in the config file are relative to this directory.
Overwrites the setting of the same name in the config file. This option is ignored when the
--bbox/-b or --polygon/-p options are used, set the output directory and name with the --output/-o
option in that case.
-H, --with-history
Specify that the input file is a history file. The output file(s) will also be history file(s).
-p, --polygon=POLYGON_FILE
Set the polygon to cut out based on the contents of the file. The file has to be a GeoJSON, poly,
or OSM file as described in the (MULTI)POLYGON FILE FORMATS section. It has to have the right
suffix to be detected correctly. Can not be used with --bbox/-b, --config/-c, or --directory/-d.
-s, --strategy=STRATEGY
Use the given strategy to extract the region. For possible values and details see the STRATEGIES
section. Default is “complete_ways”.
-S, --option=OPTION=VALUE
Set a named option for the strategy. If needed you can specify this option multiple times to set
several options.
--set-bounds
Set the bounds field in the header. The bounds are set to the bbox or envelope of the polygon
specified for the extract. Note that strategies other than “simple” can put nodes outside those
bounds into the output file.
COMMON OPTIONS
-h, --help
Show usage help.
-v, --verbose
Set verbose mode. The program will output information about what it is doing to STDERR.
INPUT OPTIONS
-F, --input-format=FORMAT
The format of the input file(s). Can be used to set the input format if it can’t be autodetected
from the file name(s). This will set the format for all input files, there is no way to set the
format for some input files only. See osmium-file-formats(5) or the libosmium manual for details.
OUTPUT OPTIONS
-f, --output-format=FORMAT
The format of the output file. Can be used to set the output file format if it can’t be
autodetected from the output file name. See osmium-file-formats(5) or the libosmium manual for
details.
--fsync
Call fsync after writing the output file to force flushing buffers to disk.
--generator=NAME
The name and version of the program generating the output file. It will be added to the header of
the output file. Default is “osmium/” and the version of osmium.
-o, --output=FILE
Name of the output file. Default is `-' (STDOUT).
-O, --overwrite
Allow an existing output file to be overwritten. Normally osmium will refuse to write over an
existing file.
--output-header=OPTION=VALUE
Add output header option. This command line option can be used multiple times for different
OPTIONs. See the osmium-output-headers(5) man page for a list of available header options. For
some commands you can use the special format “OPTION!” (ie. an exclamation mark after the OPTION
and no value set) to set the value to the same as in the input file.
CONFIG FILE
The config file mainly specifies the file names and the regions of the extracts that should be created.
The config file is in JSON format. The top-level is an object which contains at least an “extracts”
array. It can also contain a “directory” entry which names the directory where all the output files will
be created:
{
"extracts": [...],
"directory": "/tmp/"
}
The extracts array specifies the extracts that should be created. Each item in the array is an object
with at least a name “output” naming the output file and a region defined in a “bbox”, “polygon” or
“multipolygon” name. An optional “description” can be added, it will not be used by the program but can
help with documenting the file contents. You can add an optional “output_format” if the format can not
be detected from the “output” file name. Run “osmium help file-formats” to get a description of allowed
formats.
The optional “output_header” allows you to set additional OSM file header settings such as the
“generator”. If you set the value of a file header setting to null, the output header will be set to the
same header from the input file.
"extracts": [
{
"output": "hamburg.osm.pbf",
"output_format": "pbf",
"description": "optional description",
"bbox": ...
},
{
"output": "berlin.osm.pbf",
"description": "optional description",
"polygon": ...
},
{
"output": "munich.osm.pbf",
"output_header": {
"generator": "MyExtractor/1.0",
"osmosis_replication_timestamp": null
},
"description": "optional description",
"multipolygon": ...
}
]
There are several formats for specifying the regions:
bbox:
A bounding box in one of two formats. The first is a simple array with four real numbers, the first two
specifying the coordinates of an arbitrary corner, the second two specifying the coordinates of the
opposite corner.
{
"output": "munich.osm.pbf",
"description": "Bounding box specified in array format",
"bbox": [11.35, 48.05, 11.73, 48.25]
}
The second format uses an object instead of an array:
{
"output": "dresden.osm.pbf",
"description": "Bounding box specified in object format",
"bbox": {
"left": 13.57,
"right": 13.97,
"top": 51.18,
"bottom": 50.97
}
}
polygon:
A polygon, either specified inline in the config file or read from an external file. See the
(MULTI)POLYGON FILE FORMATS section for external files. If specified inline this is a nested array, the
outer array defining the polygon, the next array the rings and the innermost arrays the coordinates.
This format is the same as in GeoJSON files.
In this example there is only one outer ring:
"polygon": [[
[9.613465, 53.58071],
[9.647599, 53.59655],
[9.649288, 53.61059],
[9.613465, 53.58071]
]]
In each ring, the last set of coordinates should be the same as the first set, closing the ring.
multipolygon:
A multipolygon, either specified inline in the config file or read from an external file. See the
(MULTI)POLYGON FILE FORMATS section for external files. If specified inline this is a nested array, the
outer array defining the multipolygon, the next array the polygons, the next the rings and the innermost
arrays the coordinates. This format is the same as in GeoJSON files.
In this example there is one outer and one inner ring:
"multipolygon": [[[
[6.847, 50.987],
[6.910, 51.007],
[7.037, 50.953],
[6.967, 50.880],
[6.842, 50.925],
[6.847, 50.987]
],[
[6.967, 50.954],
[6.969, 50.920],
[6.932, 50.928],
[6.934, 50.950],
[6.967, 50.954]
]]]
In each ring, the last set of coordinates should be the same as the first set, closing the ring.
Osmium must check each and every node in the input data and find out in which bounding boxes or
(multi)polygons this node is. This is very cheap for bounding boxes, but more expensive for
(multi)polygons. And it becomes more expensive the more vertices the (multi)polyon has. Use bounding
boxes or simplified polygons where possible.
Note that bounding boxes or (multi)polygons are not allowed to span the -180/180 degree line. If you
need this, cut out the regions on each side and use osmium merge to join the resulting files.
(MULTI)POLYGON FILE FORMATS
External files describing a (multi)polygon are specified in the config file using the “file_name” and
“file_type” properties on the “polygon” or “multipolygon” object:
"polygon": {
"file_name": "berlin.geojson",
"file_type": "geojson"
}
If file names don’t start with a slash (/), they are interpreted relative to the directory where the
config file is. If the “file_type” is missing, Osmium will try to autodetect it from the suffix of the
“file_name”.
The following file types are supported:
geojson
GeoJSON file containing exactly one Feature of type Polygon or MultiPolygon, or a
FeatureCollection with the first Feature of type Polygon or MultiPolygon. Everything except the
actual geometry (of the first Feature) is ignored.
poly A poly file as described in https://wiki.openstreetmap.org/wiki/Osmosis/Polygon_Filter_File_Format
. This wiki page also mentions several sources for such poly files.
osm An OSM file containing one or more multipolygon or boundary relation together with all the nodes
and ways needed. Any OSM file format (XML, PBF, ...) supported by Osmium can be used here, but
the correct suffix must be used, so the file format is detected correctly. Files for this can
easily be obtained by searching for the area on OSM and then downloading the full relation using a
URL like https://www.openstreetmap.org/api/0.6/relation/RELATION-ID/full . Or you can use osmium
getid -r to get a specific relation from an OSM file. Note that both these approaches can get you
very detailed boundaries which can take quite a while to cut out. Consider simplifying the
boundary before use.
If there are several (multi)polygons in a poly file or OSM file, they will be merged. The
(multi)polygons must not overlap, otherwise the result is undefined.
STRATEGIES
osmium extract can use different strategies for creating the extracts. Depending on the strategy
different objects will end up in the extracts. The strategies differ in how much memory they need and
how often they need to read the input file. The choice of strategy depends on how you want to use the
generated extracts and how much memory and time you have.
The default strategy is complete_ways.
Strategy simple
Runs in a single pass. The extract will contain all nodes inside the region and all ways
referencing those nodes as well as all relations referencing any nodes or ways already included.
Ways crossing the region boundary will not be reference-complete. Relations will not be
reference-complete. This strategy is fast, because it reads the input only once, but the result
is not enough for most use cases. It is the only strategy that will work when reading from a
socket or pipe. This strategy will not work for history files.
Strategy complete_ways
Runs in two passes. The extract will contain all nodes inside the region and all ways referencing
those nodes as well as all nodes referenced by those ways. The extract will also contain all
relations referenced by nodes inside the region or ways already included and, recursively, their
parent relations. The ways are reference-complete, but the relations are not.
Strategy smart
Runs in three passes. The extract will contain all nodes inside the region and all ways
referencing those nodes as well as all nodes referenced by those ways. The extract will also
contain all relations referenced by nodes inside the region or ways already included and,
recursively, their parent relations. The extract will also contain all nodes and ways (and the
nodes they reference) referenced by relations tagged “type=multipolygon” directly referencing any
nodes in the region or ways referencing nodes in the region. The ways are reference-complete, and
all multipolygon relations referencing nodes in the regions or ways that have nodes in the region
are reference-complete. Other relations are not reference-complete.
For the complete_ways strategy you can set the option “-S relations=false” in which case no relations
will be written to the output file.
The smart strategy allows the following strategy options:
Use “-S types=TYPE,...” to change the types of relations that should be reference-complete. Instead of
just relations tagged “type=multipolygon”, you can either get all relations (use “-S types=any”) or give
a list of types to the -S option: “-S types=multipolygon,route”. Note that especially boundary relations
can be huge, so if you include them, be aware your result might be huge.
Use “-S complete-partial-relations=X” to force completion of partly completed relations. If this is set,
all relations that have more than X percent of their members already in the extract will have their full
set of members in the extract. So this allows completing almost complete relations. It can be useful
for instance to make sure a boundary relation is complete even if some of it is outside the polygon used
for extraction.
Use “-S tags=PATTERN,...” to only complete relations that have a tag matching one of the PATTERNs. So
for example if you use “-S tags=landuse,natural=wood,natural=water” everything tagged landuse=* or
natural=wood or natural=water is added to the result, but no other relations.
You can combine the “-S types”, “-S complete-partial-relations”, and “-S tags” options. The options will
be interpreted as “(types OR complete-partial-relations) AND tags”.
DIAGNOSTICS
osmium extract exits with exit code
0 if everything went alright,
1 if there was an error processing the data, or
2 if there was a problem with the command line arguments, config file or polygon files.
MEMORY USAGE
Memory usage of osmium extract depends on the number of extracts and on the strategy used. For the
simple strategy it will at least be the number of extracts times the highest node ID used divided by 8.
For the complete_ways twice that and for the smart strategy a bit more.
If you want to split a large file into many extracts, do this in several steps. First create several
larger extracts and then split them again and again into smaller pieces.
LIMITS
You can not have more than 500 extracts. Although chances are that you will be running out of memory
long before that. See MEMORY USAGE.
EXAMPLES
See the example config files in the extract-example-config directory. To try it:
osmium extract -v -c extract-example-config/extracts.json \
germany-latest.osm.pbf
Extract the city of Karlsruhe using a boundary polygon:
osmium extract -p karlsruhe-boundary.osm.bz2 germany-latest.osm.pbf \
-o karlsruhe.osm.pbf
Extract the city of Munich using a bounding box:
osmium extract -b 11.35,48.05,11.73,48.25 germany-latest.osm.pbf \
-o munich.osm.pbf
SEE ALSO
• osmium(1), osmium-file-formats(5), osmium-output-headers(5), osmium-getid(1), osmium-merge(1)
• Osmium website (https://osmcode.org/osmium-tool/)
COPYRIGHT
Copyright (C) 2013-2023 Jochen Topf <jochen@topf.org>.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software:
you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
CONTACT
If you have any questions or want to report a bug, please go to https://osmcode.org/contact.html
AUTHORS
Jochen Topf <jochen@topf.org>.
1.16.0 OSMIUM-EXTRACT(1)