[OSM-dev] Which is best for this task, osmosis, osmconvert osmupdate or...

Dave F. davefox at madasafish.com
Wed Dec 30 00:02:23 UTC 2015


Thanks for the reply.

On 29/12/2015 21:09, Paul Norman wrote:
> On 12/29/2015 9:41 AM, Dave F. wrote:
>> I've previously download a file of all OSM data within a rectangular 
>> area. I then use mkgmap to convert it to the format by my Garmin 
>> GPSr. In the future I'd like to change that so it's a multi faceted 
>> polygon of only specified OSM entities.
>>
>> At present, each time I want to update the file, I'm downloading 
>> every entity, even if they haven't been amended. What I need is to 
>> download any changes within the polygon since I last updated. I read 
>> about minute, hourly & daily diffs. Am I able to state the date I 
>> last updated as the start point for new data?
>>
>> There appear to be a few programs able to do what I require, but 
>> unsure which is best suited. Is Osmosis a bit overblown for my 
>> purpose. Osmupdate seems a bit more lightweight. Osmconvert appears 
>> to discourage doing what I need: 
>> http://wiki.openstreetmap.org/wiki/Osmupdate#Use_Cases. Overpass also 
>> has a way to download diffs. Anyone used that?
>
> Your best bet is to get an extract from Geofabrik which contains the 
> areas you need and use their daily diffs to keep it up to date. If you 
> need a smaller area, extract it from this larger file every day.

A couple of problems with that, I'm afraid. Firstly they don't provide 
my area & secondly I'm trying to avoid large downloads like the 670mb 
England file & amendment files for data I'm never going to need. Is 
there not a way to work just within a user specified polygon?

>
>> Is it better to work with a raw OSM data file or use a .pbf file? In 
>> fact I'm a bit confused what one is. From the wiki it firstly says 
>> "alternative to the XML format", but then goes on to compare it with 
>> a compressed file format. Which is it?
>
> OSM PBFs are raw OSM data, as is OSM XML and o5m. They're just 
> different file formats. Avoid OSM XML unless you're using software 
> which only supports that. Use PBF or o5m instead. PBF is easier to use 
> with the workflow I describe above since you can download a PBF 
> directly from Geofabrik.

So it's the original OSM(XML) fie format that's been compressed into a 
PBF container, similar in concept to zip files?

Cheers
Dave F.

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