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LORAN Still Worth The Trouble?
There is also another way to check this out. I load the GPS tracks
from my cruises into Google Earth as you can see here (click the image it see the GE version): http://www.rogerlongboats.com/2009September.htm Going back over my trips I can see that, in Maine at least, there is almost perfect correspondence between the Bluecharts and Google Earth. Here is a bit of the shoreline of the southwestern tip of Newfoundland traced in Bluecharts and then transferred to Google Earth. It's clearly not as accurate as in Maine. However, I don't have the detailed charts for Newfoundland unlocked and this is a trace from the larger area chart that serves as the basemap. I would have unlock the chartset for Newfoundland and redo it to see what the actual correspondence is but it will give you an idea of what can be done. http://www.rogerlongboats.com/images/GErock.jpg I've found the Bluecharts generally very accurate around the coast of Maine but on stunning error in a very well traveled channel right in Portland Harbor came to light recently when the brand new fireboat tore a shaft off and damaged most of its centerline. Here is how Bluecharts shows a section of Whitehead Passage: http://www.rogerlongboats.com/images...eadGarmin1.jpg and here is how NOAA shows it on their most detailed chart: http://www.rogerlongboats.com/images/Whitehead.jpg |
#2
posted to rec.boats.cruising
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LORAN Still Worth The Trouble?
On Fri, 27 Nov 2009 06:18:52 -0800 (PST), Roger Long
wrote: There is also another way to check this out. I load the GPS tracks from my cruises into Google Earth as you can see here (click the image it see the GE version): http://www.rogerlongboats.com/2009September.htm Going back over my trips I can see that, in Maine at least, there is almost perfect correspondence between the Bluecharts and Google Earth. Here is a bit of the shoreline of the southwestern tip of Newfoundland traced in Bluecharts and then transferred to Google Earth. It's clearly not as accurate as in Maine. However, I don't have the detailed charts for Newfoundland unlocked and this is a trace from the larger area chart that serves as the basemap. I would have unlock the chartset for Newfoundland and redo it to see what the actual correspondence is but it will give you an idea of what can be done. http://www.rogerlongboats.com/images/GErock.jpg I've found the Bluecharts generally very accurate around the coast of Maine but on stunning error in a very well traveled channel right in Portland Harbor came to light recently when the brand new fireboat tore a shaft off and damaged most of its centerline. Here is how Bluecharts shows a section of Whitehead Passage: http://www.rogerlongboats.com/images...eadGarmin1.jpg and here is how NOAA shows it on their most detailed chart: http://www.rogerlongboats.com/images/Whitehead.jpg Did they try to cut too close to G'3' ? That's one reason I'm wary of vector charts. At least the NOAA raster charts have withstood the test of time, and the rocks in Maine don't move around all that much. Welcome back, BTW. |
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