[postgis-users] generating ocean

[Christo Du Preez]

I have given that some thought, thanx. But I'd rather construct oceans, 
and as time goes on, expanding my spatial dataset.

The background solution is a bit hampered by the fact that my politacal 
boundaries aren't filled for specific reasons and also because currently 
I'm working on South Africa and flooding the background will turn it 
into an island.

David Bitner wrote:
> If you are just using this for coloring a map rather than any type of
> analysis, you could just make your background color blue.
>
> On 5/2/06, Arnaud Lesauvage <thewild at freesurf.fr> wrote:
>> Christo Du Preez a écrit :
>> > I would still like to now how to generate oceans from my country
>> > boundaries. The problem using different datasets is that the data
>> > wouldn't be an exact match, layering it might produce gaps.
>> > Ill be happy with something like a box with a hole (country 
>> boundary) in
>> > as a result.
>>
>> I believe this is what the Difference(geometry A, geometry B)
>> function does.
>> So you could use something like :
>>
>> SELECT Difference(Expand(county_geometry, 100000), county_geometry))
>> FROM country_table;
>>
>> It might use a lot of processing time / memory if the boundaries
>> are large though.
>>
>> -- 
>> Arnaud
>>
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-- 
Kind Regards,
Christo Du Preez

Senior Software Engineer
Mecola IT
http://www.mecola.com
+27 [0]83 326 8087