User:Viewfinder/OR

I have copied the material below was transferred from Talk:Huascarán. Viewfinder 06:53, 26 September 2007 (UTC)

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Farthest from Earth's center
Could we get a source on the claim that Huascarán is in a tie with Chimborazo? That isn't in accord with what I have seen. Also, it shouldn't really have to do with determining the geoid. For example, a GPS reading can in principle tell you the distance from the center directly. More practically, a GPS reading measures height relative to a standard reference ellipsoid, and adding in the ellipsoid radius at that location should give the distance from the center. Now, the given heights were not determined by GPS (although they may have since been verified by it?) but they also were not referenced to any complex model of the geoid---the figures are too old for that. They probably also use a spheroidal datum (to the extent that they are accurate at all, which can be an issue for South American peaks). So the claim about the geoid seems spurious and makes the whole claim dubious to me. -- Spireguy 03:05, 14 January 2007 (UTC)

The parameters and formulae are at Earth_radius. I knocked up a basic program:

pi=3.1415926 lat1=9.121389 lat2=1.469167 lat=lat2

p=lat*pi/180 a=6378.135 b=6356.750

t1=a*a*cos(p) r1=t1*t1 t2=b*b*sin(p) r2=t2*t2 t3=a*cos(p) r3=t3*t3 t4=b*sin(p) r4=t4*t4 r5=(r1+r2)/(r3+r4) r=sqr(r5) print r

From this I get a radial difference of 520m between the two latitudes; Chimbo's latitude is further away. According to Wikipedia, the elevations are 6768m and 6267m. But see also the geoid factor,. When extrapolated to sea level, Huascaran's location appears to be c.20m further from the earth's centre than the ellipsoid calculation indicates, in which case it is, indeed, very close.

Elevations of 6746m and 6310m are often given. If either are correct then Chimbo is the winner. I don't believe the latter, but I am not at all sure about the former.

Viewfinder 07:13, 14 January 2007 (UTC)

Thanks to Viewfinder for the numbers. I should clarify what I said earlier about the geoid. It depends on what the reference vertical data for the given elevations are. If the elevations are relative to any standard ellipsoid model, then the geoid is irrelevant. However, if they are relative to mean sea level, then the geoid is relevant, as long as one is using those figures and not, say, a modern GPS reading. Also note that if the two peaks' elevation figures use different ellipsoids, then that throws another wrench into things. Viewfinder, do you know what the vertical data for these given peak heights are likely to be?

Viewfinder correctly points out that even the given figures are pretty widely variable, so even without the issue of the geoid, the uncertainty in these figures make it hard to come to a definite conclusion.

Of course, to put it into perspective, we are talking about a percentage difference of at most 100m/6300km = 0.0016%, so maybe we should call it a tie after all. -- Spireguy 20:14, 14 January 2007 (UTC)

I have no reason not to believe the heights are relative to anything other than sea level. The 6267m for Chimborazo was from a 1993 DGPS survey by Mike Jenkins and is more SRTM compatible than 6310m. Official PIGM 100k mapping has 6746m for Huascaran; I think 6768m is from a more detailed and probably more accurate DAV (German alpine) map. Of course it would be good to get accurate ellipsoidal GPS readings. Any volunteers? Viewfinder 21:00, 14 January 2007 (UTC)


 * This is original research. Many references support the claim that Chimborazo is the farthest point of the center.  Until at least one reliable source states otherwise, wikipedia shouldn't either.  I have removed the claim from the article. Rracecarr 16:32, 23 September 2007 (UTC)

I am puttimg it back. Most of these sources make the claim on the basis that Chimborazo is 6310m, which is too high. Viewfinder 22:15, 23 September 2007 (UTC)


 * Again: THAT IS ORIGINAL RESEARCH. Find a source that says Huascaran is the furthest, or that there's a tie, or else stop putting in assertions based on your calculations. Rracecarr 23:42, 23 September 2007 (UTC)


 * Here are a few of the dozens of sources claiming Chimborazo is the furthest point from the center of the earth. I can't find one that says the same about Huascaran.  These aren't the most reliable, they're just a few from the first page of results for the google search for Everest furthest OR farthest Chimborazo OR Huascaran:


 * 

         Rracecarr 14:44, 24 September 2007 (UTC)


 * Rracecarr is correct, Viewfinder's work is original research per the Wikipedia definition, despite it being meticulously done (as always). (I am only slowly getting really careful about OR myself, as is obvious from the above; it's easy to get caught up in trying to discover the truth, as opposed to what is sourced.) One would think that there would be a Peruvian source (perhaps a wee bit nationally biased) making the claim for Huascaran, but I don't recall one offhand. Who was the person who originally put in the claim, anyway? -- Spireguy 02:52, 24 September 2007 (UTC)

It was not I; here is the claim. I subsequently checked the calculation at Spireguy's request. Sorry Spireguy, but the words "we should call it a tie" were not mine either. Wikipedia supports 6768m for Huascaran; this seems reasonable, given that it is supported by Austrian Alpine Club mapping that is more detailed and accurate than official Peruvian mapping, although it is possible that 6746m (which would end the debate) is based on a more recent survey. Given this elevation, the above calculation shows that Huascaran is in the running. The calculation is verifiable in that it can be verified by anyone who has studied mathematics to an advanced level; it should therefore be regarded as verifiable fact, not original research. The Chimborazo claim is probably correct, but it has never been proved beyond all doubt. "Reliable sources" frequently make or repeat incorrect claims in the field of topography. Viewfinder 05:54, 24 September 2007 (UTC)


 * I certainly didn't mean to imply that I was blameless in this matter; yes, as is clear from the talk page above, I was the one who first asked whether the claim was reasonable, and Viewfinder kindly did the calculations. So please emend the above to "our work is OR".
 * However the point being discussed is not who did what, but whether the calculation is OR by the Wikipedia definition. If you look at WP:NOR, you will see that this definition is very limiting in terms of what one can put into WP. As I have said, only recently have I started to take really seriously how restrictive this definition is; but it is important to stick to the rules for WP. Almost any calculation of any kind counts as OR, in the sense of synthesizing information in a novel way, not already presented in that form in a reliable source. It doesn't matter how airtight the mathematics is.
 * I agree that "reliable sources" (per the WP definition) often make errors, and I think that judgement can be applied to determine whether their statements are credible; Viewfinder has done good work in pointing out how some sources should be treated with skepticism, and I don't think that that work is OR. But including a positive claim in an article, based on a calculation done by a Wikipedian that brings together various pieces of information, is unfortunately OR, due to the particular definition used on WP.
 * With much respect, as always -- Spireguy 12:42, 24 September 2007 (UTC)

Assuming it is OK to present verifiable information, and a link to the formula that links the information, surely it is then helpful, and not against the spirit if Wikipedia, to apply that formula in a verifiable manner? Are not the OR rules aimed at editors' value judgements, which are not an issue here? Anyway, for now, I amended the "Chimborazo.. is" to "Chimborazo.. is generally regarded as", which is more true and which I hope will be accepted. Meanwhile I will try to find out more about the 6746m vs 6768m elevation (which may settle the matter in Chimbo's favour) or the current thoughts of the so-called "experts" who could provide acceptable sources. Viewfinder 14:14, 24 September 2007 (UTC)


 * I think the change to the Chimborazo article is fine. Rracecarr 14:44, 24 September 2007 (UTC)


 * Re what constitutes OR, see WP:NOR, which gives an example of a very minor, logically unobjectionable synthesis that nonetheless constitutes OR. This shows how strict the policy is supposed to be---much stricter than I would have imagined before thoroughly reading WP:NOR. The types of calculations we were doing above are another example of such a synthesis. -- Spireguy 22:40, 24 September 2007 (UTC)

--

The above mentioned example in interesting, but as I see is, there is an essential difference; a POV, rather than hard fact, is being pushed. If I can verify that A=2, B=2 and C=A+B, do I really need to find a reliable source that states that C=4 before I can post it? The above trigonometry is more complicated and requires an education in higher maths to verify, but it is still verifiable, so the same principle should apply. At the end of the day, either Chimborazo is furtherst from the earth's centre, or Huascarán is furthest from the earth's centre, and in the course of time the issue will be settled by precision measurement. By contrast, the issue of plagiarism involves value judgements which will always be the subject of debate. In such a situation, citing a manual of style that takes one position is POV pushing, because there may be other manuals which take a different position. Viewfinder 06:53, 26 September 2007 (UTC)


 * Perhaps that example was poor, since you are taking things away from it that I didn't mean to emphasize. Let me clarify my interpretation of WP:NOR by citing WP:V as well: "'Verifiable' in this context means that any reader should be able to check that material added to Wikipedia has already been published by a reliable source." Note "any reader" here. Verifiability is not a theoretical concept, it is a practical one. The verification should be transparent, at least to a reader with access to the relevant sources. Hence my interpretation of "synthesis of published material" in the WP:NOR comprises any calculation that is beyond the reach of most readers. C=A+B is unobjectionable since it is a trivial calculation. The geoid calculation is vastly different; even an expert would expend some effort on it, and most readers would have no idea whether it was correct.
 * Certainly the question of which point is farthest from the Earth's center is a matter of cold fact, but so are many questions on Wikipedia which are contested. All such questions are supposed to be addressed primarily from the standpoint of verifiability, not truth. If discerning the truth from the available data requires a non-trivial calculation, that constitutes OR. The distinction between POV and fact is not one can press too strongly on WP, given that the ultimate arbiter is verifiability.
 * Remember that I have changed my understanding on this matter over the last few months after being forced to really consider the exact WP policy. So I don't mean to lecture you, or to imply that I somehow knew this all along (which is obviously false, since I actively participated in this discussion before) but I have thought about this hard lately. It has made me more aware of how Wikipedia does not always conform to what I would want to put on the web; I would be much more willing to present original calculations and arguments, if they were transparent and well-reasoned, on a site that I operated myself. Of course most people would; but since WP is communally edited, the community has decided that such material is not appropriate.
 * I am gradually becoming more strict with myself as time goes on about this. Certainly there are old edits/creations of mine that probably, if I really was strict about it, I should go back and delete or change. I don't plan on getting that strict, and I don't plan on being the strictest enforcer of WP:NOR. (Although, for example, I did bring up the issue of "summit eminence," another example of an original synthesis.) But given that someone else brought this up regarding Huascarán, I find that I cannot disagree with the characterization of the calculation as OR.
 * One particular note about this case: I think that anytime one sees a citation entitled "see the calculation on the talk page", that is a red flag for OR. If the calculation is abstruse enough to be put on the talk page, it is probably an original synthesis. And talk pages really shouldn't have any impact on the content of an article.
 * Submitted with respect to a good friend, in anticipation of a thoughtful response, as always. -- Spireguy 02:35, 30 September 2007 (UTC)

Thank you for your comments. The question of OR versus verifiable fact seems to be a grey area; see, for example, Mount Diablo and Rock City. It still seems to me that even if a claim is not verifiable by the majority of editors, it is can still be verifiable in the literal sense if it is possible to verify it, but that seems to be a minority interpretation. Is there any clear official guideline about what is a trivial calculation and what is OR? Incidentally, a source for the Huascaran claim has now been supplied at Talk: Huascarán. Do you think it is a good enough source? Viewfinder 01:11, 4 October 2007 (UTC)


 * I would say that to the extent that a positive claim is made in the article, both examples you cite would count as OR. However as I noted before, I think that an editor can use his judgement and calculations as a reason not to accept a source as reliable, if what that source claims is contradicted by a careful calculation.
 * With reference to all of these issues/calculations, if you did them on your own website, that might count in many instances as a reliable source. Websites in general are not considered sources of the highest order (for good reasons, of course), but sites such as peakbagger are commonly cited, and your site has a similar stature. Of course you shouldn't be the one to put in citations to your website, but you could let people know on the relevant talk page of the existence of the information. I think you may have done that before.
 * As to Huascarán, the source given is a bit weak, but given that the calculations back it up, I would say that it could be included. Be bold, I say . -- Spireguy 02:25, 4 October 2007 (UTC)


 * Oh, I should have read the anon IP's posting more carefully. (I am about to respond to it on Talk:Huascarán.) The site in question clearly copied the claim from WP (verbatim). So it is most definitely not a reliable source. Oh well. -- Spireguy 02:43, 4 October 2007 (UTC)