Talk:Nautical chart

Image not very useful

I am sorry to say that Image:US NOAA nautical chart of Bering Strait.png is not overly representative: it does not look like a typical nautical chart, although it contains some relevant information. In particular, there are no coordinates, the fonts look unusual, the scale is unclear and it does not show the notes on hydrographic sources, explanations and cautions that are typical for most charts. There are also no frames for charts of other scale (which one would inevitably expect for a chart of this level of detail). The political information is very sparse (typical charts denote names of countries and borders very clearly, but this has only an inconspicuous line that may or may not an international border). All in all, it looks rather like an excerpt from a low resolution map from an electronic navigation system. Unfortunately, hydrographers are rather peculiar about their copyrights so it may be hard to find a suitable replacement. Kosebamse 09:24, 11 November 2005 (UTC)

Agreed - I've moved that image down to a new section on electronic charts, and added some scans of an older 1970s chart downloaded from the United States NOAA. CDC (talk) 03:17, 2 January 2006 (UTC)

Its image page describes exactly how the Bering Strait chart was produced, so there is no need to speculate. Given that I found the page with no picture of a chart, whether typical or not, it was an improvement! It's nice to see better examples have finally been added. I do think the thumbnails are too small; I had used 380px rather than the default 180px, so a reader could see enough detail to give a meaningful sense of the content. --KSmrq^T 09:24, 6 July 2006 (UTC)

"The top of the chart is always true north"

The current version states that "On nautical charts, the top of the chart is always true north, rather than magnetic north, towards which a magnetic compass points. "

The first part isn't strictly true - quite a few charts are oriented obliquely (e.g. river charts and much of the US Small Craft series; generally any chart of a long, thin waterway that is most easily depicted on a long, thin, folding chart). I think I have also seen a few modern charts (and certainly many historic charts) that are oriented obliquely to better fit an island on the chart.

I presume the original author was trying (rightly) to emphasis that "North" on a nautical chart is true north, not magnetic north (or grid north). I'll probably rewrite the paragraph soon, but I'm not quite sure what extra details should be included. Possibly something about the difference between a graticule and a grid, and the fact that (depending on the projection) the graticule lines are not always parallel or perpendicular, although there is probably a risk there of going off on a tangent and waffling about things that might be better off in a different section (or article). So in the meantime, does anyone have any suggestions on how it could be better expressed or explained? Wardog 16:01, 23 September 2007 (UTC)

("Encyclopedia sentences with the word 'always' in them are always wrong.") I agree -- I think the whole sentence should be deleted. Gnomonic charts are nautical charts, and often true north will be in the center of a gnomonic chart. Cheers. Haus^Talk 18:42, 25 September 2007 (UTC)

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The "Free nautical charts" part of the article seems to be an advertisement for the mapping services listed... That's not allowed, right? Seems like it has no value in helping a reader understand what a nautical chart is .... 173.79.68.101 (talk) 18:41, 25 December 2012 (UTC) IP address

I've removed it. Thanks for bringing it up. - M0rphzone (talk) 04:59, 19 April 2013 (UTC)