[postgis-users] Modeling an ocean

Steffan Chmuryk schmuryk at icisociety.ca
Thu Mar 5 19:04:24 PST 2009

Hi Dave,

A major component of shipping is currents, particularly in the open
ocean. There are many models available... If I were to propose
something, it would need to account for direction and the strength of
current. The same could be said for wind, which is harder to anticipate
on the small scale/short time frame, but still follows general patterns.
The weighting of currents would be far more significant than wind in any
model of modern shipping. You can find data on this in many places...
Here are two links:


Steffan Chmuryk
Technical Services Coordinator, ICIS
Office: 	(250) 381-9295
Cell:     	(250) 516-2481
-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
pcreso at pcreso.com
Sent: Thursday, March 05, 2009 5:08 PM
To: dave.potts at pinan.co.uk
Cc: postgis-users at postgis.refractions.net
Subject: Re: [postgis-users] Modeling an ocean

Hi Dave,

I've modelled depths, hydrographic, oceanographic & hydrological data,
but never the sort of thing you are talking about. The closest I've come
is quantitavely modeling fishing activity, but I had start/finish data
for the fishing events there.

I guess one way would to be to take something like GEBCO trackline data
to work backwards from where ships typically "go". Depth based data will
be very problematic in coastal areas, as where traffic is heavy & data
good, ships will sail with a metre or so of clearance, and this is very
tidal. In less well known areas they may require 10 to 30m of clearance.

I also know of current navigational charts where the coast is well over
a mile out from reality, so even using those for data is problematic.

Can you keep in touch with any progress you make with this? As a PostGIS
user in the maritime arena I'm always interested in such things...


  Brent Wood

--- On Fri, 3/6/09, David Potts <dave.potts at pinan.co.uk> wrote:

> From: David Potts <dave.potts at pinan.co.uk>
> Subject: [postgis-users] Modeling an ocean
> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
> Cc: postgis-users at postgis.refractions.net
> Date: Friday, March 6, 2009, 2:27 AM
> 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.
> -- 
> Any views expressed in this message are those of the
> individual sender,
> except where the sender specifically states them to be the
> views of the
> Pinan Software
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