Distance help

[ScottUK]

I am trying to get an accurate calculation of the distance in NM of a trip I did a few years back. It started in Symi and ended at Capo Carbonara at the SE corner of Sardinia. The trip was via Kythira, Messina and Ustica. Any help would be appreciated.

Cheers

[svHyLyte]

Go to Google Earth; Click on the distance measuring tool (i.e. the Ruler); click on the "Path" tab and then lay out the path/course you followed. The distance will be displayed.

[ScottUK]

cheers

[paulk]

We used this method to check the distance on one of our handicap races. The problem came in being able to focus the satellite picture well enough to actually see the buoys in it so we could mark them for the ruler.

[Boasun]

Ask the Race committee for the cordinates of the start & finish lines and of the positions of the Race buoys. Then work from there.

[puddinlegs]

Distance races... mark positions are almost alway given with lat. long. coordinates in the S.I.'s these days. To the OP, why not just pick up the charts? They always make souvenirs anyway.

[ScottUK]

I was just looking at an atlas of the Med and saw that the delivery trip I had referred to measured approximately 18 degrees from east to west and 2 degrees from north to south. So the trip, from the atlas, was about 20 degrees in distance and would constitute 1200nm. I understand travelling the rhumb line would decrease the distance but we travelled a bit south so would add distance and so pretty much negates the shortened rhumb line distance. That said, from google earth the distance measured to just over 900nm. I understand an atlas is not a precision document but the differential is 300nm so I am at a loss.

As far as picking up the charts I would prefer to get rid of a lot of my stuff rather than adding to it. Should I be sailing in the area again and need the charts I would acquire them.

Cheers

[Boasun]

Originally Posted by ScottUK

I understand travelling the rhumb line would decrease the distance but we travelled a bit south so would add distance and so pretty much negates the shortened rhumb line distance. That said, from google earth the distance measured to just over 900nm. I understand an atlas is not a precision document but the differential is 300nm so I am at a loss.
Cheers

Actually traveling the Great Circle Route is the shorter distance. But on a Mercator chart it does appear to be longer. But it isn't. Rhumb line tracks on coastal charts or larger scale charts, are good enough for general sailing. Not that much difference in the distances.

[svHyLyte]

Originally Posted by ScottUK

I was just looking at an atlas of the Med and saw that the delivery trip I had referred to measured approximately 18 degrees from east to west and 2 degrees from north to south. So the trip, from the atlas, was about 20 degrees in distance and would constitute 1200nm.

Cheers

Ah... Well, No actually.

At approximately 37º North, 1 minute of Longitude does not equal 1 NM but rather about .81 miles or, roughly, 49 miles per degree. Your trip would have been roughly 1002 miles.

FWIW...

[ScottUK]

Thanks for staightening out my oversight. Obviously that is why you use latitude to measure distances on a chart.