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
28       osmium-add-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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MEMORY USE

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

58       · osmium(1), osmium-add-locations-to-ways(1), osmium-export(1)
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60       · Osmium website (https://osmcode.org/osmium-tool/)
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62       · Index types (https://osmcode.org/osmium-concepts/#indexes)
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65       Copyright (C) 2013-2018 Jochen Topf <jochen@topf.org>.
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67       License     GPLv3+:     GNU     GPL     version     3     or      later
68       <https://gnu.org/licenses/gpl.html>.   This  is  free software: you are
69       free to change and redistribute it.   There  is  NO  WARRANTY,  to  the
70       extent permitted by law.
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CONTACT

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

77       Jochen Topf <jochen@topf.org>.
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81                                    1.10.0               OSMIUM-INDEX-TYPES(5)
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