[talk-au] National borders (was: import of state borders?)

Paul HAYDON cadmanager at live.com.au
Fri Aug 31 06:22:33 BST 2012


Hey Michael, Thanks - that made for interesting reading on a subject I knew so little about. And I agree with you, that the best course of action is to obtain the data officially.  But in the event of failure/refusal, I'm happy to help out.  BTW, in QGIS it's Vector / Geoprocessing Tools / Buffer(s) - and I seem to recall some issue with the number/scale (read: map units), but I managed to work my way through it previously.  I worked off .gpx files (my converted Magellan GPS route files), but I cannot imagine the procedure being any different as long as the data is obtained in vector format.  Like you, I might need just a slight refresher :-) See how you go with the permissions, but if there's an issue with AUS not having that border we could simply apply the buffer to the coastline in the interim, could we not?  Cheers,Paul. Date: Fri, 31 Aug 2012 06:43:42 +0200
Subject: Re: National borders (was: import of state borders?)
From: ohrosm at gmail.com
To: cadmanager at live.com.au; talk-au at openstreetmap.org

Hi Paul,

2012/8/31 Paul HAYDON <cadmanager at live.com.au>


 
I've recently used Quantum GIS (QGIS) to create a region about my GPS 
routes so as to capture the fuel stops (for example, within 10km of my 
chosen path).  I would think if someone could establish the coastline as
 a perimeter, then it could be generated by the same means.

Yes,
 the offset/buffer can be calculated with QGIS. I've done this before, 
unfortunately I didn't take any notes at that time so I would have to 
find my way again.

But the key problem is that the boundary is 
not calculated from the coastline directly. Instead of the coastline an 
artificial line called baseline is used (cf. [1]). Bascially this cuts 
off a couple of bays - (the black areas in [2]). So looking at [2] the 
baseline (and border) run from the northern tip of Fraser island 
straight west towards Bundaberg. If you would to the calculation from 
the coastline the border would rather have a bend to the south 
inbetween.

That's why I personally would prefer trying to get import permission as and only use the coastline as a backup solution.
 
I'm not sure what distance the territorial waters go to, 
That's the easy part: It's 12 nautical miles (from the baseline).



Anyway, I'd be happy to collaborate on this if you think it will help.
You're definetly welcome!

Michael

--------
[1] http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dmaritime

[2] http://www.ga.gov.au/image_cache/GA3746.pdf 		 	   		  
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