[postgis-users] Modeling an ocean

Pedro Doria Meunier pdoria at netmadeira.com
Thu Mar 5 05:53:13 PST 2009

Hi Dave,

We (MADEIRA GPS) are actually finishing a similar idea.
It has to do with ships tracking.

As for your needs:
It all falls into your tables definition...
Establish some semaphore fields defining what type of object you're describing 
and go from there.

I assume you're trying to get optimized routes for your ships, right?
Start with the most direct route to the desired location, inspect the returned 
data for any danger areas and *circumvent* them by means of a *buffer* 
starting from their boundaries.  Remember to also apply these method for the 
land mass you're going to port to.

As for the nearest neighbour on land or water that's pretty straightforward 
using a distance query. You'll want to define a field for these objects with 
a "safe-radius" value to help you circumvent them ... ;-)

Just some thoughts... :)

Pedro Doria Meunier
GSM: +351961720188
Skype: pdoriam

On Thursday 05 March 2009 01:27:57 pm David Potts wrote:
> Hi,
> I have been asked to model an Ocean by a 3rd party in terms of the
> possible movement patterns fo ships, has anybody got any suggestion on
> where to start on this issue?
> I am used to think about cost distance models, friction maps, nearest
> neighbour etc on land.  But an ocean is a different concept. Its a fluid
> mass which can change density.
> In terms of sailing its going to have areas such as sandbank, rocks,
> shipwreck sites etc which in terms of land movment patterns can be
> classified as inpassible areas,  openwater as flat land masses.
> Has anybody tried to do anything simalir?, any suggestions hints etc,
> greatly appreciated.
> Dave.

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