[OSM-dev] Suggestion about design of OSM data structure

[Shaun McDonald]

On 26 Jul 2007, at 09:57, Steve Coast wrote:
>> [...]
>> My program need to do the following tasks:
>>
>> 1. Open and read planet.osm xml file
>> 2. Trim all the nodes that are outside London's bounds -->
>> write result to file
>> 3. Trim all segments that are outside London's bounds -->
>> write result to file
>> 4. Trim all ways that are outside London's bounds --> write
>> result to file
>>
>>
>> Task 2 is very simple, just check the node's lat and lon within
>> the bounds --> after task 2 finish we have a set of nodes within
>> bounds
>> Task 3 is a little bit complicated, we need to check segment's
>> fromnodeid and tonodeid against the set of nodes within bounds --
>> >  after task 3 finish we have a set of segments within bounds
>> Task 4 is extremely complicated, we need to check way's segment
>> against the set of segments within bounds.

You should swap the order of 3 and 4 as you could end up with  
incomplete ways.

I could be wrong that this causes problems.

Shaun

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