Talk:Extreme points of the United States

little globe thingy

I just added info on Anchor Point Alaska being the westernmost point on the continuous highway system, with a ref and coordinates, but I don't know how to do the fancy little trick with the little globe that links to a map that many of the other entries have. Little help? Beeblebrox (talk) 20:01, 15 August 2009 (UTC)

Deepest / Farthest below water surface

As the claim is worded, Lake Superior is much deeper than Puget Sound. But, since Lake Superior's surface is at about 600 feet above sea level, the bottom of Puget Sound has a point that is farther below sea level than the depths of Lake Superior.

The unreferenced claim for Puget Sound that I removed called out a depth of 933 feet. With a good, although not comprehensive, look at the appropriate chart, I could not find a 933 foot depth -- the deepest sounding I found was 756 feet, between Alki Point and Decatur reef.

Unless someone can find the 933 foot depth, I will soon add the 756 foot Puget Sound depth as "Deepest depth below sea level" to the list. I will also set coords for both.. . . . Jim . . . . Jameslwoodward (talk • contribs) 11:48, 11 December 2009 (UTC)

---

The calculations here are:

• Lake Superior: Sounding is 1,333 feet. Chart datum (as given on chart 14963) is 601.1 feet above mean sea level at Rimouski, Quebec (at the mouth of the Saint Lawrence River, the entrance to the Great Lakes). Ignoring the fact that mean sea level at Rimouski may be several feet different from the general mean sea level used for other charts and maps, we can say that the deepest point in Lake Superior is 732 feet below sea level. I'm a little concerned that we're playing loose and free with precision here -- I might prefer to say "approximately 730 feet" or even "approximately 700 feet", but I think that will confuse more than it will help and it doesn't really matter as the nearest competitor is 200 feet away.

• Puget Sound: Sounding is 949 feet. Chart datum is lower low water. Mean high water, as tabulated on the chart is 10.5 feet. Mean low water is 2.8 feet. Therefore, mean sea level is 6.65 feet above the chart datum (this is not exactly right, but close enough) or approximately 7 feet when rounded appropriately. Therefore, the sounding is 956 feet below mean sea level at Madison Point, Puget Sound. The same caution that this isn't a general mean sea level applies. . . . . Jim . . . . Jameslwoodward (talk • contribs) 13:33, 18 December 2009 (UTC)

-I see now that I misread the information on chart 18446 about the surface level of the water in Puget Sound. I'm just trying to make sure I understand it now. From your calculations it seems that you're saying the mean level of the water is equivalent to sea level. Would that be correct? --Lasunncty (talk) 07:26, 19 December 2009 (UTC)

The easy answer is "yes". "Sea level" or "mean sea level", from which all elevations in this list are measured, is a construct which has many variables, but it boils down to tide gauges at many points around the coast constantly recording the height of the water. Mean Sea Level is the average of all these measurements. Since the mariner doesn't care about the Mean Sea Level, but only highs (how much clearance under a bridge) and lows (how much water under the keel), Mean Sea Level doesn't appear on nautical charts.

I approximated it as follows:

Puget Sound, like most places, has two tides each day. The two highs and two lows are not the same height. The numbers look like this, top to bottom:

• Mean Higher High Water - the average of all of the higher of the two high tides each day
• Mean High Water -- the average of all high tides
• Mean Sea Level (not on the chart) -- the average level of the sea
• Mean Low Water -- the average of all low tides
• Mean Lower Low Water -- (the chart datum) the average of all of the lower of the two tides each day.
• Extreme Low Water -- the lowest recorded water level

If you assume that the tidal level plots as a perfect sine curve each day, then Mean Sea Level would be the average of Mean High Water and Mean Low Water. Since it's not a perfect sine curve, for a variety of reasons, including rivers, the shape of the inlet, and so forth, Mean Sea Level will not be exactly the average of Mean High Water and Mean Low Water, but it will be close, probably within a foot here.. . . . Jim . . . . Jameslwoodward (talk • contribs) 12:18, 19 December 2009 (UTC)

Thank you, that makes sense. I guess the point I was getting at, though, was if you considered Puget Sound to be equivalent to "the sea". Lake Superior, for instance, is ~600 feet above sea level, but is Puget Sound at sea level? --Lasunncty (talk) 08:35, 20 December 2009 (UTC)

Good question. That's why I was careful to point out that mean sea level at Rimouski is not necessarily the same as at Puget Sound. Neither will match the datum used for elevations for the USA.

There's more than you ever wanted to know at the datum information for Seattle, the nearest reference tide station and its various helps and FAQs. . . . . Jim . . . . Jameslwoodward (talk • contribs) 16:11, 20 December 2009 (UTC)

Most remote point in all US territory

This is a candidate and is my basis for changing the claimant in Alaska to "most remote in the 50 states", but I'm not sure it's actually the most remote of all -- it needs a little more work in the Pacific to prove.

• Most remote point in all U.S. territory: Howland Island, 0°48′07″N 176°38′3″W, 422 miles (680 km) from Kanton Island, Kiribati, which itself has a population of only 41

. . . . Jim . . . . Jameslwoodward (talk • contribs) 15:59, 12 January 2010 (UTC)

coordinate precision: too much?

Some of the degree coordinates have 12 or 13 digits past the decimal point, meaning that the imprecision in the last digit is on the order of a micrometer or less. What is the rationale for such excessive precision? I am going to round these to a more reasonable precision in the meantime. Baccyak4H (Yak!) 18:07, 13 January 2010 (UTC)

I got those coordinates from the US Census boundary files for these locations. I don't know if they really measured it to that precision or not. --Lasunncty (talk) 23:39, 13 January 2010 (UTC)

Easternmost point of the USA.... by direction of travel?

I am responding to your revision to the eastern most point in the USA (Pt Udall, St Croix, USVI)

I had edited the St Croix location out of 'most eastern point' because it is not the most eastern point of the USA. The US has Pacific island territories (such as Guam) that are located farther east than any US territory in the Caribbean.

Previously, it had been stated that the St Croix point was the most eastern point 'by direction of travel'... this is a random measurement system. If you are considering it the most eastern point by direction of travel via boat, the US Pacific islands (Minor Outlying Islands) are still farther east. —Preceding unsigned comment added by 204.8.66.103 (talk) 06:27, 19 July 2010 (UTC)

Fundamentally the definition of "by direction of travel" is if you begin in the geographic center of the United States and travel to point X by the shortest possible route, then the farthest such point reachable by traveling east is Point Udall in the Virgin Islands. The points in the Pacific do not qualify because their shortest possible routes require traveling west.

Or, as a graphic example, imagine drawing a line around all US territory, shrinking the line to its minimum possible length, and filling in all the oceans within the line. The Virgin Islands would then be the farthest east you could walk on the new land mass and Guam would be the farthest west.

Or, if you prefer, use a map with the Prime Meridian at Washington DC. Such maps were common in the nineteenth century. On such a map, The Virgin Islands would have the largest east longitude and Guam the farthest west.. . Jim - Jameslwoodward (talk • contribs) 22:50, 19 July 2010 (UTC)

Thanks for your reponse. I am unable to find any definition of 'direction of travel' that correlates your definition. Please post some sites that would clarify. I am also unsure of the true value of this system of measurement in this case. It seems to cause more confusion than anything else by allowing someone to arbitrarily locate a Prime Meridian anywhere they chose. Using this logic, I could place the Prime Meridian anywhere I chose, effectively negating its practical usefulness. I could understand this being used on maps 200 years ago, but those same maps are not used today due to their 'inaccuracies'. If the extreme points of the USA are going to be listed, I don't see how this helps clarify the situation. —Preceding unsigned comment added by 204.8.66.103 (talk) 21:12, 21 July 2010 (UTC)

Sorry, I'm out of explanation -- it seems very simple to me -- it's the farthest point you can travel to in an easterly direction and still be in the USA without traveling more than half way around the world. The definition doesn't depend on where the Prime Meridian is; in fact, it ignores the Prime Meridian. And, by the way, the entirely separate question of what to use as the Prime Meridian has not been settled for as long as you think -- I own a French chart issued less than 40 years ago that shows the PM at Paris. . . Jim - Jameslwoodward (talk • contribs) 22:34, 21 July 2010 (UTC)

I also have a problem with this being the easternmost point (by travel). Very dubious distinction. If you travel East you get to The Aleutian Islands regardless of the distance traveled, it's still the furthest East. Someone I know quoted this "fact" and I thought no way. Direction of travel is also invalid. Metricmike (talk) 12:02, 25 September 2011 (UTC)

I've been to both Guam and St Croix and it entirely depends on how you measure it. If you measure from the geographical center of the US (roughly in Kansas, the furthest east you can go (without having a shorter route to the same place by going west) is St Croix. Note that their East & West geographical coordinates are irrelevant for this discussion. I COMPLETELY agree that geographically/longitudinally, Alaska claims North, East, and West. Buffs (talk) 18:11, 25 September 2011 (UTC)

This "direction of travel" for determining east west seems to be a silly construct that is unique to Wikipedia. It requires us to put the US as the center of the universe and seems to violate WP:WV--Drewder (talk) 12:15, 18 March 2012 (UTC)

Extremes of Habitation, etc.

It would be of interest to know the limits of habitation, both for private residences and for residences to which staff are posted. In particular, is the part of Alaska which is in the Eastern hemisphere inhabited at all? 94.30.84.71 (talk) 11:58, 3 July 2011 (UTC)

Also, how about considering the circumscribing circles of the whole 48 States and of the whole 50 States, both by territory and by habitation? 94.30.84.71 (talk) 11:58, 3 July 2011 (UTC)

And how about the contiguous mainland - the points which in principle be reached without crossing water? 94.30.84.71 (talk) 11:58, 3 July 2011 (UTC)

If it is legitimate to consider one point in the Amundsen-Scott South Pole Station as being southernmost, then the Station must contain a line one side of which is Easternmost by longitude and the other Westernmost. 94.30.84.71 (talk) 11:58, 3 July 2011 (UTC)

Reorganize East-West

Once again someone tried made a 'correction' based on not reading or not understanding the information in the detailed note at the bottom of the article, clearly referenced at the end of the lead. This might be avoided in the future if we had separate sections

• Easternmost & Westernmost in the contiguous states
• Easternmost & Westernmost by longitude
• First sunrise & last sunset

The last two sections could begin with introductory text taken from notes section. Any comments? YBG (talk) 06:45, 27 January 2012 (UTC)