[OSM-talk] We Need to Stop Google's Exploitation of Open Communities

[MP]

 On Tue, 12 Apr 2011 10:58:05 +0200, Erik Johansson wrote:
> On Tue, Apr 12, 2011 at 1:06 AM, Frederik Ramm <frederik at remote.org> 
> wrote:
>> Hi,
>>
>> Bernhard Zwischenbrugger wrote:
>>>
>>> Where can I access the OSM data?
>>>
>>> I know it is possible to download the hole planet, setup a 
>>> database,...
>>> but that's not an easy task.
>>
>> Not easy, but possible, and done by literally hundreds of people all 
>> over
>> the world.
>
>
> I would place downloading the planet on the same level as compiling a
> kernel. Not really hard, but something most Ubuntu users are scared 
> of
> doing.

 Downloading is the easy part (if you have reasonably fast connection), 
 but making actually some use to it is the worse part - you need lot of 
 disk space depending on what you want to do (tens of GB with OSM3S, 
 hundreds of GBs for importing into postgres, etc ...) and lot of CPU 
 time (probably over a day) to convert/import the planet into something 
 that can be further used. And if you get "lucky", the import process 
 gets killed at 85% by OOM killer or some other fault and you can start 
 again.

 But it is same for wikipedia - merely reading it on web is simple, but 
 if you want an offline copy, you'll start with 6.7GB compressed XML dump 
 and after spending some time with attempts to import this into local 
 database, soon you'll find out that you need to download some .sql files 
 to speed up the import (so wikimedia won't need to recalculate all the 
 links between articles) and you need to somehow download all the images 
 that are used (you need to write some script for that or perhaps check 
 the net to find if someone already did that). Not exactly easy either.

 But unlike wikipedia, in OSM there are extracts, which have usually 
 some reasonable size (you can pick a continent of interest, or just the 
 country, or for some large countries like france and germany, extracts 
 for regions are also available).

 Cutting smaller parts like entire city from the extract with osmosis is 
 then quite easy and fast (several minutes, perhaps an hour at maximum)

 Martin