Difference between revisions of "IWRAP Training Seminar February 2010"

The second IWRAP training seminar was held at St.Germain en Laye February 16-18, 2010.

A number of aspects of IWRAP were discussed at the seminar, some of which are documented below:

Lateral Distribution bar width

Problem: (Igor) When establishing a lateral distribution based on AIS data, you would obtain the basic distribution through numerical analysis of AIS data. For this you would need to select a with of each rectangular bar of the distribution, after which you would fit a suitable lateral distribution within the IWRAP tool.

The shape of the (mathematically) fitted distribution will change, depending on the width you select for the numerical analysis...

Should the width of the numerical tabs not be selected carefully, perhaps as a function of the width of the ships passing the passage line?

Discussion: (Erik) Yes, your right, you need to experiment a little with the width of the tabs. If you make them to narrow, you will not get any distribution.

Solo Ship Kollision?

Problem: (Esa) A ship is alone in the world. It sails with a speed of 10 knots back and forth between point A and B which are 10 nautical miles apart. In one year the ship has made 12*365 = 4380 voyages. If this is modelled by one leg, length 10 nautical miles with volume of traffic being 4380 voyages each way, IWRAP yields a number of collisions...... How is this possible since the ship is alone in the world?

Discussion: IWRAP assumes that each voyage is independent of all other voyages, so in the IWRAP world it is possible for the ship to encounter itself going the other way :-)

Minor bugs found in Version 2.2.0a

Result view - On legs using uniformal distribution, the distribution is not rendered in geographic result view.