[OSM-talk] Overpass API - Fetching countries, their capitals, and their borders

Warin 61sundowner at gmail.com
Wed Aug 14 02:21:58 UTC 2019


On 14/08/19 11:39, Wayne Emerson, Jr. via talk wrote:
> He wasn't asking for every town on earth. Just every country's border, 
> and every country's capitol. I am a noob too so can't answer his 
> question. But I did run the wizard with "admin_level=2 and type:node" 
> and got 3,988 nodes. Which begs the question, why does Argentina have 
> dozens of admin level 2 nodes? I am guessing around 80 or so.

Each border would usually be a relation with a number of ways. Each way 
will have a number of nodes to make the way.


Example
Argentina is relation 286393

https://www.openstreetmap.org/relation/286393#map=4/-40.51/-63.63

It has 2 nodes, many ways and a number of separate relations... look at 
teh above link.

One of those ways is Way: Border Chile - Argentina (206446254) and that 
single way has 393 nodes.

>
> On 8/13/2019 6:30 PM, Warin wrote:
>> On 14/08/19 07:41, L??o El Amri via talk wrote:
>>> Hello,
>>>
>>> I'm trying to fetch countries, their borders, and their capitals 
>>> through
>>> Overpass API, but the server never replies to me (With a timeout:3600
>>> setting, the server reply with a 502 error after a while).
>>> I'm only a beginner with this API, so maybe my request is not 
>>> efficient:
>>>
>>> (
>>> ???? node[place=city];

this gets all cities?
>>> ???? node[place=town];
this gets all towns?
>>> )->.a;
>>> rel[boundary=administrative][admin_level=2]->.b;
>>> (
>>> ???? node[place=country];
>>> ???? node.a[capital=yes];
>>> ???? way[boundary=administrative][admin_level=2];
>>> ???? .b;
>>> ???? .b >;
>>> )->.o;
>>> .o out body;
>>>
>>> What am I doing wrong ? (Should I use another tool for this purpose ?)
>>>
>>
>> Too much data? So it times out.
>>
>> You are asking for every node of;
>>
>> city 19,930
>>
>> town 111,981
>>
>> country 221
>>
>> And then boundaries as well. 29,752
>>
>> The numbers I got from taginfo.. did not bother with separating nodes 
>> etc.
>>
>> I think the boundaries will cause problems - lots of nodes and ways 
>> in there as well as the relations.
>>
>> Suggestions? Do it in small sections.
>>
>> Get the cities and countries as one item and see if that works. Save 
>> the result for later merging.
>>
>> Get the boundaries for a small section of the world .. with few 
>> boundaries and see if that works.
>>
>>
>>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk/attachments/20190814/4f73f114/attachment.html>


More information about the talk mailing list