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What are the (equator-based) latitude and (Greenwich-based) longitude coordinates of this marker? —Preceding unsigned comment added by 216.47.188.16 (talk) 20:27, 8 September 2008 (UTC)
Does anyone know where the coords given on the page came from? This BLM page says lat 45-31-11 and long 122-44-34. I've seen different numbers given elsewhere--mostly in rather old sources. As I look into principal meridians I am seeing that the coords given in earlier times were likely off, with modern surveying, GPS, etc, providing better precision and accuracy. As a result sources are likely to differ over the coords. As I understand it though, even if a principal meridian was defined as, say, 122-44-34 longitude, if it later was discovered that the survey monuments placed on the ground were not exactly on that longitude it did not mean that the legally defined meridian (and all derived range and township lines, real property lines, etc) were shifted on the ground. Rather the precise location of the monuments, baselines, meridians, etc, were found to have slightly different coordinates than previously thought. This would make it slightly tricky to describe on a page like this. Perhaps something could be said about this aspect of land surveying and examples given of the coords determined by early surveys compared to more recent coords? I'm not sure, just thinking out loud. I'd like to make a new page about the Willamette Meridian specifically, if I find the time. For now I'm mainly curious about where the coords given on this page came from. Anyone know? (perhaps when coords are added to a page the source ought to be mentioned in a comment or something--can't footnote a coord template...) Pfly (talk) 21:26, 3 October 2009 (UTC)
Okay, I used the GPS coords to update it. Obviously, there are more WP:Vish ways to do it, but it's better than what was there previously (by 298 feet). It also matches the PMP measurements to within 17 feet, which is actually the error my GPS calculated. So perhaps their OR is better than my OR. = tedder (talk) 01:46, 15 October 2009 (UTC)
In 1983, the North American Datum shifted from the prior NAD27 (1927) to NAD83 (1983), see: https://en.wikipedia.org/wiki/North_American_Datum At the position of the Willamette Stone, the shift would have changed measured GPS values by about 95 meters, about 300 feet. (mostly in changed longitude, a much smaller amount in changed latitude.) https://en.wikipedia.org/wiki/North_American_Datum#/media/File:Datum_Shift_Between_NAD27_and_NAD83.png This probably explains a lot of the confusion as to the varying Lat/Lon values we have seen. The article should be re-written to explain to lay people why the GPS values differ between the pre-1983 published values, and what they currently see if they use their smartphones and a GPS app. Also, within the last 2 years, some newer smartphones have begun using dual-frequency GPS signals, employing both L1 and L5 signals, which are dramatically more accurate than L1-only, single frequency GPS recivers previously employed. https://insidegnss.com/galileo-hits-the-spot-testing-gnss-dual-frequency-with-smartphones/ I just bought one. I think this article should include the best-known Lat/Lon for the Stone based on the current NAD83. I will go to the Stone and record the GPS value and post it here on this Talk Page. Sure, you can call that original research (OR), and yes, it should shortly be augmented with an 'official', published value. But perhaps that measured value will help us identify which published value is likely to be the correct one. Aside: Google search is great for finding text. But in this specific case, what we could use is a search that is 'GPS-aware', or at least 'number-aware': Suppose we are looking for a GPS coordinate which we believe to be "lat 45-31-11 and long 122-44-34" (values arbitrarily taken from a comment above.). What we'd like to find is some value published on the Internet which is 'close to' that coordinate, but successfully find it even if the numerical values in the last few digits of the number are slightly off. An additional confusing factor is that GPS coordinates can be displayed as DDD.dddddd, or DDD MM.mmmm, or DDD MM SS.sss. (D=degree, M=minute, S=second). Does anyone know if there is a mechanism for finding what might be the 'correct' value? Allassa37 (talk) 22:17, 12 March 2021 (UTC)
Okay, I have gone to the Willamette Stone, and used a dual-frequency GPS smartphone, plus the app Precision GPS, to measure the Lat/Lon of the stone. The averaging clock time was about 10 minutes and 30 seconds. The result was: 45 degrees, 31 minutes, 10.3407 seconds North, -122 degrees, 44 minutes, 38.1621 seconds West. What is the resolution? I believe that one minute of arc of latitude is 6,000 feet, so one second of arc is 100 feet, and a hundredth of a second of arc is 1 foot. As for longitude, those values are approximately multiplied by 1/(Square Root 2), so a minute of distance at about 45 degrees is (6000 feet/1.414), or 4,243 feet, one second is 4,243/60 = 70.7 feet, and a hundredth of a second is 0.707 feet, or about 8.5 inches. This site https://www.lat-long.com/Latitude-Longitude-1952647-Oregon-Willamette_Stone.html shows some values: Degrees Minutes Seconds: Latitude: 45-31'10 N Longitude: 122-44'37 W Decimal Degrees: Latitude: 45.5195621 Longitude: -122.7437089 It appears that the figure for decimal degrees more-precisely states the value. I will convert the decimal degrees of latitude to minutes and seconds, by first multiplying the portion after the decimal point by 60: 0.5195621 x 60 = 31.173726. And multiplying 0.173726 x 60 = 10.42356 Or: 122 degrees, 31 minutes, 10.42356. However, the precision justified by those 7 digits past the "Decimal" degrees, 7 digits, only seems to justify about 1/3000 of a second of arc resolution. Similarly, for the longitude, multiplying 0.7437089 by 60 results in: 44.622534. Multiplying 0.622534 x 60 results in: 37.35204. Or, 122 degrees, 44 minutes, and 37.35204 seconds. Similarly, only 1/3000 after the seconds decimal point is justified, or about 37.3520 seconds. Allassa37 (talk) 06:54, 19 March 2021 (UTC)
This seems like a competently done survey: https://www.plso.org/Resources/Documents/PLSOJuneJuly2009_web.pdf As stated on Page 16: "Okay, so, I’ve got to let the cat out of the bag. All of you surveyors out there must be wondering, “Come on Greg, just exactly where is the Willamette Stone?” Latitude 45°31'10.23551" North, Longitude 122°44'37.89866" West. The elevation is only published to the nearest foot, so that should settle the positional reliability issue, at least vertically, for all of you “least squares” jar heads." Allassa37 (talk) 06:54, 19 March 2021 (UTC)
A discussion is taking place to address the redirect Willamette Stone and Willamette Meridian. The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 November 19#Willamette Stone and Willamette Meridian until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Mdewman6 (talk) 19:36, 19 November 2021 (UTC)