[osmosis-dev] Merge huge count of files

[Igor Podolskiy]

Hi,

>  > What is the best strategy to merge a huge count (e.g. 100x100 matrix)
>  > together with a minimum of needed memory?
>
> You don't say what kind of files you are merging but it is possible that
> the best strategy is not using Osmosis at all for this task.
>
> If you have plain simple OSM XML files then the following will merge
> them super fast:
>
> (echo '<osm version="0.6">'; cat *osm|grep -v "<osm"|grep -v
> "</osm"|grep -v "<?xml"; echo '</osm>') > newfile.osm
yes, except that you will want to grep out the <bound> elements too 
since having more than one of them is not good at all (some tools might 
trip over it, Osmosis will for sure):

(echo '<osm version="0.6">'; \
   cat *osm|grep -v "<osm"|grep -v </osm"| \
   grep -v "<?xml"; \
   grep -v "<bound"; \
   echo '</osm>') > newfile.osm

Of course, if you don't have <bound>s in the source files, it isn't a 
problem.

Bye
Igor