Talk:Rhumbline network

Merging Proposal to Portolan Chart

It would be incorrect to merge it to to Portolan Chart for there are plenty of mapamundi that use the Rhumbline network and by no means can be considered portolan charts (they do not have any PORT-harbour on them)

• Map_of_Juan_de_la_Cosa
• Cantino_planisphere
• Teixeira planisphere

--Mcapdevila (talk) 21:34, 20 October 2015 (UTC)

This can be removed. The discussion is at Talk:Portolan chart#Merger proposal. RockMagnetist(talk) 21:48, 20 October 2015 (UTC)

• To better follow the three merge proposals all discussions have been copied to User:Mcapdevila/Rhumbline-merge. --Mcapdevila (talk) 08:42, 10 November 2015 (UTC)

Unclear tag

If there is any unclear point, please.. the first thing to do is reading the discussion link ( Talk:Portolan chart#Merger proposal) not adding labels.. wich makes it even more unclear.. because does not say wich is the point that is unclear.. any unclear point has been clarified in this discussion, by experts that have written books about it, so pse. instead of adding tags.. detail wich is the unclear point... the same article has been translated to 5 languages and nobody finds it "UNCLEAR".--Mcapdevila (talk) 18:08, 9 August 2018 (UTC)

Different rhumbline concepts

The assertion:"Rhumbline network is rendered doubly redundant by the article Rhumb line" it's not exact.. for its primitive name was "winds network" (from italian "griglia dei venti") not related at all to the english concept developed in the rhumbline article!.. they are just "false friends" using the same name (600 years away from each other).. I've added it to the article to avoid misinterpretations..--Mcapdevila (talk) 22:28, 20 October 2015 (UTC)

There is some logic in RockMagnetist's reasoning. However he departs from the false assumption that only portolan charts depict rose-wind systems (this is a better way of calling it because those lines are not true loxodromes). The fact is those systens of lines (rhumbs) irradiating from certain points of the charts were adopted in other cartographic models, such as the latitude chart of the Atlantic (from about 1500 on) and even the Mercator chart (from 1569 on). I agree that the distinction between loxodromic and orthodromic navigation is not relevant here. Only in 1537, in a treatise of the mathematician Pedro Nunes (Treatise in defense of the nautical chart), was such distinction made for the first time. Anyway, orthodromic navigation was (and is) seldom used by mariners (I know, I am a navy officer). I hope these considerations help. Alvesgaspar (talk) 20:42, 21 October 2015 (UTC)

please study alvesgaspar very ..very interesting paper with proven knowledge and your confusion will vanish, then I think you will realize that it's beter for en.wiki to leave the article "rhumbline network" as it is (& pse. remove the merge label),..for what Bagrow says

By the way.. it's a fact that there are "Lines" in the windroses.. so.. how do you want to call them other than "windrose lines"?(forget Rose-wind that I like but maybe doesn't exist.. so I've changed it..)..Therefore, we don't need any English-language sources to call "windrose lines" some lines that are forming a windrose.. the same happens with "windrose network" that it's a network composed by a few windroses. It's the essence of English-language, isn't it?--Mcapdevila (talk) 08:59, 30 October 2015 (UTC)

Merger proposal

Transcluded here from the discussion of the portolan chart where all the doubts of future readers are perfectly clarified.

--Mcapdevila (talk) 10:50, 30 April 2023 (UTC)

The article Rhumbline network is mainly about portolan charts, and is rendered doubly redundant by the article Rhumb line. I propose merging its content into this article. RockMagnetist(talk) 15:59, 20 October 2015 (UTC)

It would be incorrect to merge Rhumbline network to Portolan Chart for there are plenty of mapamundi that use the Rhumbline network and by no means can be considered portolan charts ('they do not have any PORT-harbour on them')

• Map_of_Juan_de_la_Cosa
• Cantino_planisphere
• Teixeira planisphere

--Mcapdevila (talk) 21:34, 20 October 2015 (UTC)

Would it make sense to merge it with Rhumb line, then? RockMagnetist(talk) 21:50, 20 October 2015 (UTC)

The assertion:"Rhumbline network is rendered doubly redundant by the article Rhumb line" it's not exact.. for its primitive name waswinds network (from italian griglia dei venti) not related at all to the english concept developed in the rhumbline article they are just false cousins using the same name(600 years away from each other).. I've added it to the article to avoid misinterpretations..--Mcapdevila (talk) 22:28, 20 October 2015 (UTC)

I'm not convinced. In Rhumbline network, I don't see any definition that would distinguish the lines from rhumb lines.The existence of an Italian term for it is no evidence that it is really different. In Portolan chart, rhumb lines represent constant compass directions. The definition in Rhumb line is equivalent, but more general as it applies to ocean crossings as well. RockMagnetist(talk) 00:44, 21 October 2015 (UTC)

Then we should have to merge it with both rhumb line and orthodrome.. In the Med for the portolan your assertion would be true but not in the planispheres (wich do not follow the mercator projection) If one "submerges" its eyes into the catalan or italian maps of that time and studies them (I've been doing it for the last 55 years, my father made me a present of a facsimil of Cresques planisphere in my 15th aniversary 23-10-1945).. one is able to read the names of those lines wich were winds: Tramontana, levante, ponente, mezzogiorno, greco, sirocco,lebegio.. together one can see that they follow both rhumb line and orthodrome or neither of them, due to the imprecision of the map making of that time, being the rhumb line only almost true in the Mediterranean portolan charts and a complete mess (for its in-exactitude) in the Texeira planisfere (and the others mentioned before)

Today, after the mercator projection, we have two concepts clearly distinct loxodromic navigation and orthodromic navigation and the thousands of english speaking sailors (as my coleague and sailing friend Rodney Pattisson), map makers, etc.. they know perfectly that fact..--Mcapdevila (talk) 08:31, 21 October 2015 (UTC)

I'm impressed by your knowledge of maps, and would like to be sure that we come up with a solution that you agree is correct. I think the main issue is, what is a rhumb line? If that is settled, then a rhumbline network is just a network of rhumbs, and not really a separate concept. We need to answer this question for the English language; maybe the meanings are different in Italian, but that's not relevant here. For convenience, I am going to quote the Oxford English Dictionary meaning. Rhumb line is equivalent to the first sense of rhumb, which is:

1 a. The line or course followed by a ship or other vessel sailing in a fixed direction. Also: an imaginary line on the earth's surface intersecting all meridians at the same angle and used as the standard method of plotting a ship's course on a chart

(I'm not sure what a "fixed direction" means if it's not based on geographic or magnetic meridians.) RockMagnetist(talk) 17:29, 21 October 2015 (UTC)

I don't think the distinction between loxodromic and orthodromic navigation is relevant here; even in modern navigation manuals, a rhumb line is clearly identified with constant bearing, never with great circles. See, for example, the Admiralty Manual of Navigation and The Flight Navigator Handbook. Similarly, some directions may have been associated with winds, but wind directions aren't very reliable. Correct me if I'm wrong, but I would guess that in the Cresques planisphere, the directions for the lines were chosen by some other method, after which the wind labels were added. RockMagnetist(talk) 17:29, 21 October 2015 (UTC)

• There is some logic in RockMagnetist's reasoning. However he departs from the false assumption that only portolan charts depict rose-wind systems (this is a better way of calling it because those lines are not true loxodromes). The fact is those systens of lines (rhumbs) irradiating from certain points of the charts were adopted in other cartographic models, such as the latitude chart of the Atlantic (from about 1500 on) and even the Mercator chart (from 1569 on). I agree that the distinction between loxodromic and orthodromic navigation is not relevant here. Only in 1537, in a treatise of the mathematician Pedro Nunes (Treatise in defense of the nautical chart), was such distinction made for the first time. Anyway, orthodromic navigation was (and is) seldom used by mariners (I know, I am a navy officer). I hope these considerations help. Alvesgaspar (talk) 20:42, 21 October 2015 (UTC)

At the end some clever words from Alvesgaspar that I think should clarify the case: "..rose-wind systems (this is a better way of calling it because those lines are not true loxodromes)..".. I have created loxodromic navigation and orthodromic navigation to explain that it was with the mercator projection (1569), that a rhumb line could be represented by a straight line.. rose-wind lines from the portolans (1275).. are straight lines.. therefore -for Reductio ad absurdum- they can't be loxodromic (today's rhumblines).. otherwise the mercator projection would have been invented in 1275..they are false friends (inside english language) that lead RockMagnetist to the actual confusion.. By the way... it would be of interest reading the doctoral paper of Mr Hurtado where he explains the portolan projection as the addition of multiple azimuthal projections with multiple centers -like today's Google maps- (the best explanation-theory I've found in 55 years)... but this would be like opening Pandora's box..--Mcapdevila (talk) 06:36, 22 October 2015 (UTC)

Alvesgaspar, Mcapdevila: If anything, I am more confused after all this explanation than before. I'm finding it difficult to see just how the above considerations apply to the question at hand - should there be an article rhumbline network, or should it be redirected somewhere? Are there English-language sources that call the rose-wind lines "rhumblines" when they are not loxodromic? Should the article redirect to Rose-wind network instead of the other way around? RockMagnetist(talk) 01:43, 28 October 2015 (UTC)

RockMagnetist, please study alvesgaspar very ..very interesting paper with proven knowledge and your confusion will vanish, then I think you will realize that it's beter for en.wiki to leave the article rhumbline network as it is (& pse. remove the merge label),..for what Bagrow says

By the way.. it's a fact that there are "Lines" in the windroses.. so.. how do you want to call them other than "windrose lines"?(forget Rose-wind that I like but maybe doesn't exist.. so I've changed it..)..Therefore, we don't need any English-language sources to call "windrose lines" some lines that are forming a windrose.. the same happens with "windrose network" that it's a network composed by a few windroses. It's the essence of English-language, isn't it?--Mcapdevila (talk) 08:59, 30 October 2015 (UTC)

RockMagnetist, there isn't worst blind that the one doesn't want to see.. ,they are false friends.. using your linguistic argument we can end like the spaniard who translated (s.XVII) "Canal de la Manche" (Sleeve in French) for "Canal de la Mancha"(Stain in spanish) instead of Manga.. the article rhumbline network can not be merged to rhumbline (which 'today' is phisicaly a loxodrome), because, to be loxodromes, the straight lines drawn in the portolan charts... they should be outlined on top of a "mercator projection map -or similar-" (1569) and we have a fact agreed by all scholars: "they aren't outlined on top of a "mercator projection map", therefore, they couldn't be loxodromes in the XIII, XIV, XV centuries.. (see my previous reductio ad absurdum).. Do you realize the time we are wasting here instead of doing some more positive work?..As I have done adding a definitive reference to the "articles in question" and to Catalan map.. As leo Bagrow states:"..the word ("Rhumbline") is wrongly applied to the sea-carts of this period, since a loxodrome gives an accurate course only when the chart is drawn on a suitable projection. Cartometric investigation has revealed that no projection was used in the early charts, for which we therefore retain the name 'portolan'."--Mcapdevila (talk) 08:05, 6 November 2015 (UTC)

RockMagnetist, the first problem here is that the term “rhumb” had no precise meaning when it came into use. It applied equally well to the windrose lines as it did to loxodromes because the term only applied “locally” and only meant whatever a sailor did in order to sail with constant bearing, with all the imprecision that that implies. Therefore “rhumb” was applicable to the straight lines on portolans when portolans were in use, as well as always applicable to straight lines on Mercator charts. For short distances portolan “rhumbs” do not meaningfully differ from Mercator rhumbs, but these days “rhumb” is synonymous with the mathematically precise “loxodrome” because it has been made synonymous retrospectively.

I do not believe “rhumbline network” is a real term (I defer to Alvesgaspar here) and therefore there shouldn’t be an article by that name. The Rhumbline network article needs a huge amount of work in any case. It may merit remaining independent precisely to explain the historical context and why the portolan network is not quite the same thing as a network of rhumbs. The article should be referenced from Rhumb line, Portolan chart, Mercator projection, World map and wherever else. The important concept it captures is the network of straight lines on maps intending to show sailing routes (without truly implying a precise path), as well as windrose networks. Those networks do not mean the same thing (mathematically) on every kind of map, but graphically they are all the same thing. Therefore the article describing them should make the history and purpose of such networks clear, but also make clear that they do not describe quite the same thing on each kind of map. Strebe (talk) 15:25, 6 November 2015 (UTC)

• I agree in general. However the proposal was to merge the article with Portolan chart, which would be incorrect since those wind-rose systems were also depicted in non-portolan charts (e.g. latitude charts and Mercator charts). Alvesgaspar (talk) 16:39, 6 November 2015 (UTC)

Sorry it has taken me so long to reply. It has been difficult for me to find the time to think about how to sort out this confusing tangle. Let me start by discussing a few facts about articles. First, rhumbline network is in the See also section of several articles, but it is only linked in the text of two, Portolan chart and Catalan chart. Those two, plus the section Rhumblines vs. windrose lines, have identical text referring to windrose networks and windrose lines (both of which point to rhumbline network, making a closed loop from the latter section).

The other thing to note is that Rhumbline network is a pretty mixed bag. Its heart is the section on network design, which is mostly about wind roses; much of the information is already in Compass rose (Wind rose is reserved for the meteorological term). Vellum map creation process also duplicates some of this information, and says very little about vellum itself. Planispheres with double hexadecagon is just a couple of images of Cantino planisphere and Teixeira planisphere, which have their own articles. And finally, Use of rhumblines is a sentence fragment. In short, there really isn't anything here that isn't better deleted or moved somewhere else.

Strebe: The best place to discuss the history of the term "rhumb" would be Rhumbline. Alvesgaspar: I agree that a redirect to Portolan chart is not the best idea, and there doesn't seem to be any support for it anyway. I will therefore change the target to Compass rose. RockMagnetist(talk) 07:26, 8 November 2015 (UTC)

• Note: I have changed the target of the merger proposal to Compass rose - see the new discussion at Talk:Compass_rose#Merger_proposal. RockMagnetist(talk) 07:36, 8 November 2015 (UTC)

@Rockscientist. I am afraid I am not seeing the point of these merger proposals. Why so eager to get rid of this article? Seems fine by itself, it can be connected from many other articles. Walrasiad (talk) 09:05, 8 November 2015 (UTC)

@Rockscientist. excuse my imperfections I've rewritten the Use of rhumblines as you've demanded.--Mcapdevila (talk) 17:48, 9 November 2015 (UTC)

Thanks, Mcapdevila. I have decided to drop the whole merge idea. RockMagnetist(talk) 18:09, 9 November 2015 (UTC)