[OSM-talk] osmarender bounding box cropping

Thom Shannon thom at glow-internet.com
Tue Oct 30 16:58:49 GMT 2007


Just come up with a much simpler idea! Add a couple of nodes to the osm 
data with a made up tag, add a render rule for the tag, build the SVG 
then read out the coords of those nodes, they can then be removed from 
the svg.

Thom Shannon wrote:
> Yes I am basically building a custom tile maker here! I should 
> probably just hack a copy of tiles at home, I used to do a lot of perl so 
> I'll have a crack at that. Thanks
>
> Dirk-Lüder Kreie wrote:
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>> Thom Shannon schrieb:
>>   
>>> When you download your osm data based on a bounding box you get the 
>>> whole of any ways with nodes in that box, which is of course quite 
>>> sensible. But when you render your SVG, the map you were hoping up ends 
>>> up down in the corner somewhere because of a big bit of coast or 
>>> motorway sticking out.
>>>
>>> I'm thinking if I go through the nodes in the osm data and find the 
>>> extreme outer points in all four directions, then work backwards I can 
>>> figure out the coordinates in the SVG document where my original 
>>> bounding box would be. The only problem is I'm not sure what kind 
>>> projection osmarender uses to convert the lat/lon coords to a grid.
>>>
>>> Any ideas on the best way to do this?
>>>     
>>
>> This is the exact same problem tilesAtHome has solved already. I'd have
>> to look at the code to tell you what exactly is done. to get the right
>> bbox...
>>
>> - --
>>
>> Dirk-Lüder "Deelkar" Kreie
>> Bremen - 53.0952°N 8.8652°E
>>
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>>   
>
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Glow New Media
t: 0151 707 9770
m: 07730 987 574
www.glow-internet.com

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32-36 Hanover Street
Liverpool
L1 4LN

Map: http://tinyurl.com/2f5nxd
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