[osmosis-dev] Cutting PBF file into 1° tiles

[Sylvain Melin]

On 18/04/2016 11:00, Jochen Topf wrote:
> On Mo, Apr 18, 2016 at 10:10:06 +0200, Sylvain Melin wrote:
>> My plan is to :
>> - exploit a planet sized pbf file
>> - cut it into 1° tiles using osmosis
>> - filter and extract the data from these tiles as shapefiles using libosmium
> If you are writing your own program anyway to create those shapefiles, why
> don't you do the splitting in this step *after* creating the geometries and
> before writing them into shapefiles? That is probably much easier to do than
> based on the PBF due to the structure of the OSM data files.
>
> Jochen
Maybe I'm wrong but because I don't want to parse the full 
planet.osm.pbf every time I want to extract a small set of data.
The processing time seems to grow exponentially with the size of source 
file so having an intermediate level with 1° sized pbf containing 
everything seems very practical to me.

Also, my osmium program loops over the target tile and parse the 
appropriate pbf :

/for each j in [-90,89]//
//{//
//        for each i in [-180,179]//
//        {//
//                create osmium::handler//
//                parse i_j.pbf with osmium::io::Reader//
//                extract data to single handler with osmium::apply//
//        }//
////}/

Do you think it would be more efficient to have a single big PBF and 
extract data to several handlers ?
Is it even possible without filling the RAM ?

/for each j in [-90,89]//
//{//
//        for each i in [-180,179]//
//        {//
//                create osmium::handler//
//        }//
//}//
//
//parse world.pbf with osmium::io::Reader//
//extract data to all handlers with osmium::apply

/Thank you for your help./
/
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