bionic (5) osmium-index-types.5.gz

Provided by: osmium-tool_1.7.1-1_amd64 bug

NAME

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

DESCRIPTION

       The  osmium  add-locations-to-ways and osmium export commands have to keep an index of the node locations
       in memory or in a temporary file on disk while doing their work.  There are several different  ways  this
       can be done which have different advantages and disadvantages.

       Use the --show-index-types, -I option on these commands to show all available index types.  It depends on
       your operating system which index types are available.

       Use the --index-type, -i option on these commands to set the index type to be used.

       The default index type is flex_mem which will keep all data in memory and works  for  small  extracts  as
       well as the whole planet file.  It is the right choice for almost all use cases if you have enough memory
       to keep the whole index in memory.

       For the osmium export command, the special type none is used  when  reading  from  files  with  the  node
       locations on the ways.  (See osmium-add-node-locations-to-ways(1) for how to get a file like this.)

       You  can  use  one  of  the  file-based  indexes  for the node location store to minimize memory use, but
       performance will suffer.  In this case use sparse_file_array if you have a small or medium sized  extract
       and dense_file_array if you are working with a full planet or a really large extract.

MEMORY USE

       It depends on the index type used how much memory is needed:

       • For sparse_*_array types 16 bytes per node in the input file are used.

       • For dense_*_array types 8 bytes times the largest node ID in the input file are used.

       The *_mem_* types use potentially up to twice this amount.

       The *mem* and *mmap* types store the data in memory, the *file* types in a file on disk.

       The  flex_mem  type  automatically  switches  between  something similar to sparse_mmap_array for smaller
       extracts and dense_mmap_array for larger extracts or the whole planet file.

       If you specify the --verbose, -v option, Osmium will display how much memory was used for the index.

SEE ALSO

osmium(1), osmium-add-locations-to-ways(1), osmium-export(1)

       • Osmium website (http://osmcode.org/osmium-tool/)

       • Index types (http://osmcode.org/osmium-concepts/#indexes)

       Copyright (C) 2013-2017 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 http://osmcode.org/contact.html

AUTHORS

       Jochen Topf <jochen@topf.org>.

                                                      1.7.1                                OSMIUM-INDEX-TYPES(5)