Glad to see the interests on this topic from the list.
Here is a link to a project done at the Center for Geographic Analysis at Harvard, specifically addressing this issue:
http://gis.harvard.edu/publications/trafficked-sea.
The author is my colleague Stacy Bogan, copied here.
Wendy
________________________________________________________
Wendy Guan, Ph.D. 1737 Cambridge Street, K022
Executive Director Cambridge, MA 02138
Center for Geographic Analysis 617-496-6102 (office)
Harvard University 617-496-5149 (fax)
http://gis.harvard.edu [log in to unmask]
-----Original Message-----
From: Guan, Wendy
Sent: Wednesday, November 12, 2014 4:23 PM
To: 'Andy Anderson'; 'Milan Budhathoki';
Cc: Stacy Bogan <[log in to unmask]>
Subject: RE: Finding Distance between points over water
See http://gis.harvard.edu/publications/trafficked-sea
-----Original Message-----
From: Andy Anderson [mailto:[log in to unmask]]
Sent: Monday, November 10, 2014 11:39 AM
Subject: Re: Finding Distance between points over water
To remove the tedium, write a Python script.
Remember, though, that distance calculations depend on the projection you use. If you want the cost-path from, say, New York to Sydney, there is no single projection that will give you an accurate measure.
A better approach might be to determine the standard shipping lanes, calculate the distances (if you can't find them in a table), and piece together routes.
More generally, you could set up an iterative algorithm to calculate distances using spheroid-based angular calculations with restrictions based on open water (e.g. at 40° north latitude, longitude will be restricted to roughly -74° to -9° and 128° to 140° and 142° to -124°).
- Andy
On Nov 10, 2014, at 9:13 AM, Milan Budhathoki <[log in to unmask]<mailto:[log in to unmask]>> wrote:
Looks like email that I sent yesterday didn't go through.
Here it is again:
Hello Listserv,
I have point dataset of ship trips from one port to another. I want to calculate the shortest distance between each port pair over water. There are thousands of voyages, and 5,000 unique ports from all over the world. One of the approach I can use in ArcGIS is to run the Cost-Path tool having water/land as a cost raster to make a path only on water. But I assume that the Cost-Path approach would be little tedious for a large dataset. I wonder if anyone in this forum has a suggestion to calculate a shortest distance between two points having restricted path.
I will highly appreciate your feedback.
--
Milan Budhathoki
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