[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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