1OSMIUM-INDEX-TYPES(5)                                    OSMIUM-INDEX-TYPES(5)
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NAME

6       osmium-index-types - Index types used to store node locations
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DESCRIPTION

9       The  osmium  add-locations-to-ways  and  osmium export commands have to
10       keep an index of the node locations in memory or in a temporary file on
11       disk while doing their work.  There are several different ways this can
12       be done which have different advantages and disadvantages.
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14       Use the --show-index-types/-I option on  these  commands  to  show  all
15       available index types.  It depends on your operating system which index
16       types are available.
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18       Use the --index-type/-i option on these commands to set the index  type
19       to be used.
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21       The  default  index type is flex_mem which will keep all data in memory
22       and works for small extracts as well as the whole planet file.   It  is
23       the  right choice for almost all use cases if you have enough memory to
24       keep the whole index in memory.
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26       For the osmium export command, the special type none is used when read‐
27       ing  from  files with the node locations on the ways.  (See osmium-add-
28       node-locations-to-ways(1) for how to get a file like this.)
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30       You can use one of the file-based indexes for the node  location  store
31       to  minimize memory use, but performance will suffer.  In this case use
32       sparse_file_array if you have a  small  or  medium  sized  extract  and
33       dense_file_array  if  you  are  working  with a full planet or a really
34       large extract.
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36       When using the file-based index types (*_file_array), add the  filename
37       you want to use for the index after a comma to the index types like so:
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39       ... -i dense_file_array,index.dat ...
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MEMORY USE

42       It depends on the index type used how much memory is needed:
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44       · For  sparse_*_array  types  16  bytes  per node in the input file are
45         used.
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47       · For dense_*_array types 8 bytes times the  largest  node  ID  in  the
48         input file are used.
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50       The *_mem_* types use potentially up to twice this amount.
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52       The  *mem*  and *mmap* types store the data in memory, the *file* types
53       in a file on disk.
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55       The flex_mem type automatically switches between something  similar  to
56       sparse_mmap_array  for smaller extracts and dense_mmap_array for larger
57       extracts or the whole planet file.
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59       If you specify the --verbose/-v option, Osmium will  display  how  much
60       memory was used for the index.
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SEE ALSO

63       · osmium(1), osmium-add-locations-to-ways(1), osmium-export(1)
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65       · Osmium website (https://osmcode.org/osmium-tool/)
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67       · Index types (https://osmcode.org/osmium-concepts/#indexes)
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70       Copyright (C) 2013-2020 Jochen Topf <jochen@topf.org>.
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72       License      GPLv3+:     GNU     GPL     version     3     or     later
73       <https://gnu.org/licenses/gpl.html>.  This is free  software:  you  are
74       free  to  change  and  redistribute  it.   There is NO WARRANTY, to the
75       extent permitted by law.
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CONTACT

78       If you have any questions or  want  to  report  a  bug,  please  go  to
79       https://osmcode.org/contact.html
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AUTHORS

82       Jochen Topf <jochen@topf.org>.
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86                                    1.12.1               OSMIUM-INDEX-TYPES(5)
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