Talk:Universal Transverse Mercator coordinate system

message: first table two collums long(range)-UTM 0-60
 second table LAt(range)-UTM A-Z
 or is it the otheray around 
 I'll but this on my to do later list :)
--Mkouklis 12:06, 16 September 2006 (UTC)
thread_title:  A couple of tables?  

message: In the entry, it says: "This is in longitude zone 17, and the grid position is 630084m east, 4833438m north." How do you notate.
:There isn't really a standard notation, but there are conventions.  The easting should be given before the northing.  This would likely be most common way to write out that position:
::630084 mE 4833438 mN zone 17
:However, since the easting is usually given first, and the easting always has one less digit than the northing, that position could be given as: 6300844833438 zone 17.  That particular style of notation isn't used very frequently anymore. - Justin 23:12, 25 October 2006 (UTC)
replies: text: Note that you would also want to include which zone 17 (eg, 17T 630084E 4833438N).  Some notations add an initial zero to easting to give it the same number of digits as northing.  Also, some GPS receivers I have used switch the order and give Northing/Easting, but the general convention seems to be easting first.Shouriki 00:22, 5 May 2007 (UTC)
thread_title:  Notation? 

message: UTM is not map projection.  The Universal Transverse Mercator coordinate system consists of 60 zones, each of which is defined by a unique point of origin, false easting, and Transverse Mercator projection centered over a specific central meridian with a scale factor of 0.9996  The UTM coordinate system (which is the subject of this article) is a system by which locations can be specified on the globe.  It uses map projections.  It uses 60 specifically defined Transverse Mercator projections (60 out of an infinite number of possible Transverse Mercator projections) but it itself is not a map projection. - Justin 23:50, 27 October 2006 (UTC)
thread_title:  UTM is not a map projection 

message: There's a bad link to MTM (Modified Transverse Mercator), which I cannot find anywhere. 70.66.184.59 01:53, 25 January 2007 (UTC)
thread_title:  Bad see also link 

message: Am I to understand that each lettered zone is conceived of as a perfect trapezoid, or are the east and west edges curved?--Homunq 21:41, 26 June 2007 (UTC)
replies: text: That is like asking whether the equator is curved or straight: it depends on what projection the map is drawn in. In a regular cylindrical projection, like Miller or ordinary Mercator, each grid zone (like 33U) appears as a perfect rectangle. However, suppose a grid zone is drawn in the UTM projection that belongs to its own zone. Then the east and west edge appear slightly curved and convex; the edge that faces the equator usually appears more curved and convex (unless it coincides with the equator: then it appears straight); the edge that faces the nearest pole also appears curved, but concave. For example, the boundary between 33U and 34U is a meridian that appears slightly curved like this ")" when drawn in UTM projection of zone 33, but appears curved the other way, "(", when drawn in UTM projection of zone 34.  --Mikael R 17:47, 4 December 2007 (UTC)
thread_title:  Trapezoidal? 

message: I think this is in error. The latitude zones are not part of UTM as defined in DMATM 8358.2.  They are part of the Military grid reference system defined in DMATM 8358.1, which is based on UTM.
--David Garfield 01:19, 27 July 2007 (UTC)
replies: text: You are right in theory, I think.  In pure UTM notation, one would specify the hemisphere (North or South) instead of the latitude band.  But using UTM zone + latitude band letter + UTM coordinates has become a quite common notation: it might be called a de facto standard.  Therefore, it is no longer a good idea to use "N" and "S" to stand for north or south hemisphere, since they can be mistaken for latitude band letters.  One could write "North" and "South" instead (if everyone knows enough English).  Since at least one character is needed to distinguish the North and South hemisphere, why not accept the latitude band letter for this purpose?  Some extra redundancy should be a good thing, since some errors might be caught.  --Mikael R 17:56, 4 December 2007 (UTC)
thread_title:  "UTM latitude zone" 

message: I tried it allready in the first part of the article, but my english is not god enough to correct this in the article itself, so let me explain here: As I understand it, it is not correct, that... 
   
"Distortion of scale increases in each UTM zone as the boundaries between the longitude zones are approached."
The distortion increases with the *metric* distance to the central meridian, thats why the west to east width of the UTM-Zones is limited to 800 km, btw. exactly 800 km, and that not because of the distortion but due to the concept that all eastings should have *6 digits*. That leads to the smallest valid easting of 100.000, and 900.000 as the biggest for symetry  reasons (100 + 400 = 500 (central meridian) + 400 = 900km). The Zones overlap widely. 
Btw. because of that, the "Norway-execption" isn't a real (systematic) eception: At these latitudes even the even zones overlap each other, witch means, in the north there are *no* places, than can only be mapped   to one UTM-Zone 
may be http://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Utmzylinderrp.jpg/180px-Utmzylinderrp.jpg
helps to understand?
  
87.160.209.176 22:52, 13 October 2007 (UTC)
thread_title:  Overlap of zones 

message: Speaking as an idiot, I came to some grief as a consequence of ignorance over map projections and specifically UTM. Popular schoolboy impression of Mercator is a projection of the globe onto a cylinder. It isn't, it's carefully rescaled for conformality. The issue of conformality isn't very visible -0 you can Google UTM and search hard to find out a precise definition, and I thought it would be helpful to highlight that, so that anyone else contemplating coding up UTM would at least refer to e.g. Snyder. Please amend/delete if you disagree.  —Preceding unsigned comment added by Monopodia (talk • contribs) 14:49, 28 December 2007 (UTC)
thread_title:  Idiots' caveat addition 

message: I propose the following changes in nomenclature to eliminate
confusion in the UTM entry:
*Longitude Zone -> "UTM Zone" or just plain Zone
*Latitude Zone -> Latitude Band (the terminology from the MGRS documention)
*The combination UTM Zone + Latitude Band -> Grid Zone (again this is MGSR terminology)
I also propose the following clarifications:
*The use of the Latitude Band in UTM is twofold:
**(primarily) in the exceptions in the division of the globe into UTM zones
**as optional way of specifying a UTM coordinate, e.g.,
    17T 630084 4833439
and of course the grid zone is an integral part of the MGRS.
*Document more clearly the use of the hemisphere in place of the latitude band in a UTM coordinate, e.g.,
    17N 630084 4833439
pointing out the possibility of confusion, see the last page:
    http://earth-info.nga.mil/GandG/coordsys/grids/utm_ups.pdf
and emphasizing the need to specify which convention is in use.
I'm planning on making these changes in a few days.  Comments? 
Cffk (talk) 12:21, 24 October 2008 (UTC)
thread_title:  Conflicting notations (latitude band vs hemisphere) for UTM coordinates 

message: The link in the References section is no longer valid:
http://www1.nga.mil/ProductsServices/GeodesyGeophysics/GPSPreciseEphemeris/Related%20Documents/utm_ups.pdf  —Preceding unsigned comment added by Hedgehog0 (talk • contribs) 10:13, 11 March 2009 (UTC)
thread_title:  Broken Link 

message: I believe that the statement under the "history" section that projections from a cylinder are not conformal is misleading.  While it is true that standard mercator projections are not conformal, transverse mercator is considered conformal for scales of 1:500K and larger.  Suggest removing this comment or changing it to say that "transverse mercator projections are considered confirm (meaning they preverse the shape) for scales of 1:500K and larger".  This is especially true in the case of UTM which excludes the polar regions.  —Preceding unsigned comment added by 72.196.233.140 (talk) 01:49, 23 March 2009 (UTC)
thread_title:  Conformal Projection  

message: In the section Locating_a_position_using_UTM_coordinates 
it has links to pages easting and northing and point of origin.
In point of origin it states that:
The coordinates of the origin are always all zero, for example (0,0) in two dimensions and (0,0,0) in three.
But in the Locating section it states:
The point of origin  of each UTM zone is the intersection of the equator and the zone's central meridian. In order to avoid dealing with negative numbers, the central meridian of each zone is given a "false easting" value of 500,000 meters. Thus, anything west of the central meridian will have an easting less than 500,000 meters. For example, UTM eastings range from 167,000 meters to 833,000 meters at the equator (these ranges narrow towards the poles).
If the central meridian has a "false easting" value of 500,000 then how can it be the point of origin as described on that page?
On the easting and northing page it states that:
When using the Universal Transverse Mercator coordinate system, northing is the distance to the equator, while easting is the distance to the "false easting", which is uniquely defined in each UTM zone.
If this is true, then the value of 500,000 for the central meridian means 500,000 m to the "false easting" which, according to this section, is the central meridian!  So the central meridian has a value of 500,000 and that means 500,000 m to the central meridian?  Also, the statement When using the Universal Transverse Mercator coordinate system, northing is the distance to the equator doesn't seem to jibe with the Locating section:
In the northern hemisphere, positions are measured northward from the equator, which has an initial "northing" value of 0 meters and a maximum "northing" value of approximately 9,328,000 meters at the 84th parallel  — the maximum northern extent of the UTM zones. In the southern hemisphere, northings decrease as you go southward from the equator, which is given a "false northing" of 10,000,000 meters so that no point within the zone has a negative northing value.
A value of 9,400,000 would not be 9,400,000 m to the equator.  It would be in the southern hemisphere, 600,000 m from the equator. (as I understand the Locating section)
So the 
Locating_a_position_using_UTM_coordinates 
section and the easting and northing and point of origin pages don't seem to be in agreement.  I think the point of origin page is probably right and the Locating_a_position_using_UTM_coordinates section is wrong.  I think the easting and northing is probably wrong and the Locating_a_position_using_UTM_coordinates section is correct.
But regardless, those pages are supposed to be authoritative on those subjects and this page and section should be in agreement with them.
My Wikipedia (talk) 17:44, 29 September 2010 (UTC)
replies: text: Agreed, this section is still extremely confusing, six years later.  The phrase "central meridian" gets redefined, and the description of how to avoid negative numbers makes no sense as written.  It desperately needs to be cleaned up by somebody good at writing clear English, ideally with an explanatory graphic.  I would make an attempt, but I can't figure it out myself.  107.135.140.113 (talk) 20:14, 23 May 2016 (UTC)
replies: text: Is it any better now? Strebe (talk) 22:01, 23 May 2016 (UTC)
thread_title:  confusion in [[Universal_Transverse_Mercator_coordinate_system#Locating_a_position_using_UTM_coordinates |''Locating a position using UTM coordinates'']] section 

message: Could anyone add a section about the advantages, if any, of the UTM system over other coordinate systems?   --Roland 03:46, 17 January 2011 (UTC)
replies: text: I second that request. I'm trying to reasons why UTM or Section/Township/Range would be desirable, because I can't think of any good ones. Ufwuct (talk) 20:14, 4 April 2012 (UTC)
thread_title:  Advantages of the UTM System over Other Systems? 

message: I just don't like the first sentence in the section with the simplified formulas.  There are no "exact formula's", all formula's are series expansions.  In addition, all the formula's that I have seen are "usable", they are just more complicated.  Accuracy is pretty important here and I would recommned that this just be presented as a simplified formula as a point of reference.  — Preceding unsigned comment added by Tomcard (talk • contribs) 19:32, 11 November 2011 (UTC)
thread_title:  Coordinate Transformations 

message: I would like to make a few observations on the previous topics. Interested watchers should read the article on the Transverse Mercator projection: all references quoted are to be found there. The detailed seies are in the article  Transverse Mercator: Redfearn series.
:#There is an exact form of the transverse Mercator projection. The analytic formulae, involving incomplete elliptic integrals, were obtained by E.H. Thompson in 1945 but not published until a paper of L.P.Lee in 1976 (ref8). This solution is very interesting because it is a bounded projection--it does not tend to infinity in any direction. See illustration in Transverse Mercator projection.
:#The exact solution provides a yardstick against which approximate series solution may be assessed. Two such approximations were published by Kruger in 1912 (ref6): one is an expansion (the lambda-series) in the longitude measured from the central meridian and the other  an expansion (the n-series) in the flattening parameter . The latter is more accurate over a given interval in longitude.
:#The lambda-series is the one chosen for the UTM projections. The details of the full series are given in J.P.Snyder, Working manual, and in the US Defense Mapping Agency (Hager et al) manual (ref14). The formulae given in the  Transverse Mercator: Redfearn series  are those used by the OSGB: they differ only in sub-millimeter terms.
:#To agree with the "official" UTM maps one must use the same formula in calculating transformations. The n-series should not be used. The fact that the n-series is more accurate is irrelevant.
:#The so-called "simplified formulae" are based on the n-series. This is quite misleading and I suggest that this section be deleted. I personally consider these formulae to be horrendously complicated and not at all transparent. If it is felt necessary to have formulae in this article,  as against refs to TM article and the online literature, I would advocate restoring the previous formulae based on truncated lambda-series (but with refs to actual series used). I have meant to do this for some time but perhaps someone else can have a go.
:#Finally, I suspect that the simplified series introduced by user 官翁 (talk | contribs)‎ were in fact put in place by the same Kawase he references. This is a case of a user introducing his own original research on a wiki page. The same has been done in Meridian arc.
:*Peter Mercator (talk) 12:09, 23 July 2012 (UTC)
thread_title:  More on coordinate transformations 

message: I have again unpacked the horrendous expression given for A_0. The truncated series is entirely in keeping with the truncated expressions for the other term. Please remember that this is a geodesy page: it is not a mathematics article. The concept of the product over the empty set will be unknown to most readers who arrive here: it has clearly confused at least two readers already. The generalisation to an arbitrary term is irrelevant here. Once again may I suggest that this material goes to the page  Transverse Mercator: flattening series. Comments from third parties please.  Peter Mercator (talk) 09:07, 10 September 2012 (UTC)
replies: text: Amen. I do not understand the rationale for providing an infinite series for one element when the rest consists of truncations. Strebe (talk) 04:16, 11 September 2012 (UTC)
thread_title:  More on simplified series 

message: Many old military etc maps were published using the World Polyconic Grid (WPG), which preceded UTM. Please add info about this to the article and WP. Are there any online tools for converting from WPG? -96.237.4.73 (talk) 20:55, 9 January 2013 (UTC)
thread_title:  World Polyconic Grid 

message: A user might benefit if the article specifically indicates that all geographic coordinates in the formulae are given in radians. It has done so for distances specifying kilometers. However, the formula for λ0 suggests it is given in degrees. That value must be converted to radians before applying the result elsewhere - a conversion that could be missed by the inattentive user.
RomanKal (talk) 21:03, 14 June 2015 (UTC)
replies: text: It does not matter if you use degrees or radians. You just can’t mix up your units. Strebe (talk) 04:05, 16 June 2015 (UTC)
thread_title:  Indicate Units Employed in Formulae 

message: Using proj notation, we see the UTM/TM relationship is not that complicated after all,
 +proj=utm +lon_0=123
 +proj=tmerc +lon_0=123 +x_0=500000 +k=0.9996
are the same. Maybe use this as an example. Jidanni (talk) 21:53, 2 January 2016 (UTC)
thread_title:  We see the UTM/TM relationship is not that complicated after all 

message: User:Ciciban, could you please render this in lucid English? It's a circumlocution of some sort whose meaning I can only guess at. Strebe (talk) 21:37, 2 March 2016 (UTC)
replies: text: Ist the meaning clear to you now?Yours, Ciciban (talk) 05:27, 3 March 2016 (UTC)
replies: text: No. We don't attribute statements from citations to specific people in article bodies. User:Ciciban, what do you mean by "contrast", and why do you call the cited work "popular"? How is it popular? Aren't you really saying the cited work is wrong? Strebe (talk) 20:25, 3 March 2016 (UTC)
replies: text: Dear Strebe,We don't attribute statements from citations to specific people in article bodies. — how would that inhibit you in comprehending my sentence?In contrast to — the meaning is explained here.Popular— in that it is the source, all other sources boil down to, according to the paper by Buchroithner and Pfahlbusch. And yes, according to Buchroithner and Pfahlbusch it's wrong. Is there any contradiction between popularity and wrongness?Please, stop complaining and start making suggestions. My feeling is that your objections guide me nowhere. I am shure that we have a common interest in developing the article.Have a nice weekend.Yours, Ciciban (talk) 11:58, 4 March 2016 (UTC)
replies: text: Apologies for mixing in the comment about in-line attribution; that is a separate matter and I should have stated it separately. I have changed the text to something I consider more clear and encyclopædic. I read Buchroitner & Pfahlbusch’s paper. It doesn’t say anything about “popular”. It also feels rather nationalistic, judgmental, and unreasonably concludes definitively that the US system is based on the German without entertaining alternative explanations. I’m surprised the reviewers let it slip through with some of the incorrect and even self-contradictory statements: In the first paragraph of the introduction, it (correctly) states that Snyder 1993 gives no indication of the projection’s origin, but the final paragraph of the introduction includes Snyder 1993 (incorrectly) in the list of sources that claim UTM was invented by Americans. Also incorrectly in that list are Yang, Snyder, and Tobler 1999; Kennedy and Kopp 2001; Hofmann-Wellenhof, Lichtenegger, and Collins 2001. I don’t have access to the only other reference, which is a German periodical, but given that four out of five patently do not say what this paper claims is disappointing and concerning. Strebe (talk) 08:35, 5 March 2016 (UTC)
replies: text: Thanks a lot — Ciciban (talk) 07:21, 6 March 2016 (UTC)
thread_title: ''In contrast to a popular presentation''

message: I suggest the passage:"This projection is conformal, so it preserves angles and approximates shape but distorts distance and area." should be changed to "This projection is conformal, so it preserves small shapes but distorts areas.". Because that would avoid implying that conformal projections get two things right, and draw attention to the alternative characteristic of an equivalent or equal area projection. Jayjay4547a (talk) 11:13, 29 November 2016 (UTC)
replies: text: Preserving angles implies preserving local shapes. I amended the text. I don't think "getting two things right" (if the reader even draws that conclusion) necessarily prejudices the reader toward conformal and away from equal-area. Strebe (talk) 19:13, 29 November 2016 (UTC)
thread_title: Describing Conformal projections

message: In the section defintions->UTM zone it is sugggested that a zone of 6° longitude would have a largest width of 800 km. I fail to see how this can be true. The Equator is approx. 40077 km wide. Divided by 360 degrees leaves a maximum degree-length of 112 km. A zone of 6° will be no wider than 668 km. I edited the article accordingly. 82.217.111.143 (talk) 11:39, 7 August 2017 (UTC)
thread_title:  6° = up to 800km? 

message: In the section about simplified formulas, at the end of the page, a is defined as the Earth radius and used in the first four formulas. The next ones use A which is not defined and I assume is the same as A.  This should be clarified or corrected. Pot (talk) 17:08, 18 June 2021 (UTC)
replies: text: Like many other variables in the formulae, 'A' is an intermediate value used in later calculations. It is not 'a', as should be clear from its definition in terms of 'a'. Intermediate values are normal in mathematical descriptions. Strebe (talk) 18:06, 18 June 2021 (UTC)
thread_title:  a and A are used interchangeably in formulas 

message: may you all tell me 27.109.113.245 (talk) 05:11, 20 May 2023 (UTC)
thread_title:  Where are the numbers zero of the joints grid zone?