4 ms·

Gott-Goldberg-Vanderbei may have a lower error, but its usefulness is also significantly reduced. My favourite for world maps is still Winkel Tripel (https://e

Gott-Goldberg-Vanderbei may have a lower error, but its usefulness is also significantly reduced. My favourite for world maps is still Winkel Tripel (https://en.wikipedia.org/wiki/Winkel_tripel_projection https://en.wikipedia.org/wiki/Winkel_tripel_projection). Winkel-Tripel was given one of the best ranks by Gott and Goldberg, before they developed the projection in the OP. Winkel Tripel used to be the standard until Google Maps came along and pushed everyone back to using Mercator for data visualization and political maps.

defrost 3y ago
The triple was|is a damn fine world projection. My favourite for "local area" usage was the old New Zealand Map Grid .. not a polyconic projection, rather a custom complex polynomial optimised to reduce grid error in toto (by multiple metrics) for the North and South Islands of New Zealand. As a topographic grid projection it was aligned with the "spine of best fit" of the two islands, rather than stright up North|South aligned, and weighted to minimise the N|S and E|W distortion within the land region of interest as distance from the centre zone increased. https://www.linz.govt.nz/guidance/geodetic-system/coordinate-systems-used-new-zealand/projections/new-zealand-map-grid-nzmg https://www.linz.govt.nz/guidance/geodetic-system/coordinate... There were very few (three ?) in use about the world pre WGS84 .. and like many things went the way of the Dodo, the Krasovsky 1940 ellipsoid, the Bessel 1841, and all those tens and tens of other ellipsoids, datums, and projections of days yore.
- bradrn 3y ago
  > My favourite for "local area" usage was the old New Zealand Map Grid .. not a polyconic projection, rather a custom complex polynomial optimised to reduce grid error in toto (by multiple metrics) for the North and South Islands of New Zealand. Paper link: https://www.linz.govt.nz/resources/research/conformal-mapping-projection-minimum-scale-error https://www.linz.govt.nz/resources/research/conformal-mappin...
  - defrost 3y ago
    That's the paper alright, I've got a physical copy in a filing cabinet somewhere :-) IIRC, for anyone else looking for a curio, there was one state|county|region in the USofA that used a custom conformal projection for a local grid system pre 1980s .. somewhere outside the regular PLA mapping grids.
    - saalweachter 3y ago
      I don't think this is the one you're thinking of, but in NYC the subway maps (which are not particularly geographically accurate) are drawn with Manhattan vertical, rather than on its 20-something degree tilt.
      - defrost 3y ago
        > subway maps (which are not particularly geographically accurate) Subway maps and bus maps in cities are very typically not geographically accurate map projections .. the focus tends to be on a compact stylisation that represents connections for travel plans. Historically Roman Road maps were on a scroll and very linear, today the UK underground tube maps are displayed in a manner that aids commuters in making connections. I'm not all that familiar with NYC subway maps (only there for a short time in the 80s .. and who can recall their youth?) but I remember them being more "graphic" rather than "geographic". I'm thinking more of a local land projection map that would have been used for local surveying in the days prior to global GPS .. but thanks for the thought all the same!
        theluketaylor 3y ago
        The NYC MTA map is pretty geographic by metro map standards. There are some obvious distortions, like Manhattan being wider than it actually is and it's not actually vertical as noted before. It also includes a lot of surface street and neighbourhood references. Most metro maps just focus on station names. Compared with something like the London Tube map or Paris Metro map it's extremely geographic. https://new.mta.info/map/5256 https://new.mta.info/map/5256
playworker 3y ago
Oblig: https://xkcd.com/977/ https://xkcd.com/977/
- deleted 3y ago
  [deleted]
- nox101 3y ago
  And West Wing: https://www.youtube.com/watch?v=vVX-PrBRtTY https://www.youtube.com/watch?v=vVX-PrBRtTY
jschrf 3y ago
IIRC the use of Web Mercator is primarily for ease of generating 256×256 tiles. The ideal projection is simply 3D, as it accounts for all scales, and the geoid if so inclined.
- zokier 3y ago
  > The ideal projection is simply 3D, as it accounts for all scales Unless you have 3D display that is not really true, it is still projected to 2D; perspective projection is still projection and it is not obvious that it's in any way "ideal" for maps
  - TheBicPen 3y ago
    Sure, but it can be projected in a way that minimizes distortion of the current region you're looking at. 3D effectively allows you to choose the best projection from an infinite family of projections, while 2D restricts you to a single projection regardless of your location of interest.
orangeboats 3y ago
My personal favorite map projection is the Equal Earth projection (https://en.wikipedia.org/wiki/Equal_Earth_projection https://en.wikipedia.org/wiki/Equal_Earth_projection) but it seems like it is relatively unknown. Though in general I have a soft spot for all equal-area projects, except the abomination Gall-Peters.
taeric 3y ago
I'm assuming someone has made a graph of error versus utility in map projections? Not being able to draw straight lines is a fairly useful thing to do. If you want accurate, it is also silly to insist on it being a static 2d projection? Having a globe is not exactly difficult.
- lalaithion 3y ago
  A globe is just using physics to create a perspective projection on your retina. https://en.wikipedia.org/wiki/General_Perspective_projection https://en.wikipedia.org/wiki/General_Perspective_projection
  - taeric 3y ago
    Right? And that isn't hard and can get you accurate images. I get that this was a lot harder in the past. But today, this isn't difficult at all.
  - Retric 3y ago
    Not quite, you have two retina and local light sources. So you get more information from a globe than any 2d projection. However by rotating a perspective projection your brain can better recreate the underlying 3D nature of earth.
liotier 3y ago
To me, Kavrayskiy VII still feels like the most balanced compromise among general-purpose pseudocylindrical projection - more so than Winkel Tripel, and of course miles ahead of Mercator but that isn't even a contest.
- twic 3y ago
  Agreed. The only thing i have against Kavrayskiy VII is that i learned about it from the XKCD about map projections, which makes me feel like a complete fraud.
trylfthsk 3y ago
I'm partial to the Pierce Quincuncial [0] projection myself. Actually, any conformal projection that tiles really. [0]https://en.wikipedia.org/wiki/Peirce_quincuncial_projection https://en.wikipedia.org/wiki/Peirce_quincuncial_projection
- contravariant 3y ago
  Technically Mercator tiles.

defrost 3y ago

The triple was|is a damn fine world projection. My favourite for "local area" usage was the old New Zealand Map Grid .. not a polyconic projection, rather a custom complex polynomial optimised to reduce grid error in toto (by multiple metrics) for the North and South Islands of New Zealand. As a topographic grid projection it was aligned with the "spine of best fit" of the two islands, rather than stright up North|South aligned, and weighted to minimise the N|S and E|W distortion within the land region of interest as distance from the centre zone increased. https://www.linz.govt.nz/guidance/geodetic-system/coordinate-systems-used-new-zealand/projections/new-zealand-map-grid-nzmg https://www.linz.govt.nz/guidance/geodetic-system/coordinate... There were very few (three ?) in use about the world pre WGS84 .. and like many things went the way of the Dodo, the Krasovsky 1940 ellipsoid, the Bessel 1841, and all those tens and tens of other ellipsoids, datums, and projections of days yore.

bradrn 3y ago
> My favourite for "local area" usage was the old New Zealand Map Grid .. not a polyconic projection, rather a custom complex polynomial optimised to reduce grid error in toto (by multiple metrics) for the North and South Islands of New Zealand. Paper link: https://www.linz.govt.nz/resources/research/conformal-mapping-projection-minimum-scale-error https://www.linz.govt.nz/resources/research/conformal-mappin...
- defrost 3y ago
  That's the paper alright, I've got a physical copy in a filing cabinet somewhere :-) IIRC, for anyone else looking for a curio, there was one state|county|region in the USofA that used a custom conformal projection for a local grid system pre 1980s .. somewhere outside the regular PLA mapping grids.
  - saalweachter 3y ago
    I don't think this is the one you're thinking of, but in NYC the subway maps (which are not particularly geographically accurate) are drawn with Manhattan vertical, rather than on its 20-something degree tilt.
    - defrost 3y ago
      > subway maps (which are not particularly geographically accurate) Subway maps and bus maps in cities are very typically not geographically accurate map projections .. the focus tends to be on a compact stylisation that represents connections for travel plans. Historically Roman Road maps were on a scroll and very linear, today the UK underground tube maps are displayed in a manner that aids commuters in making connections. I'm not all that familiar with NYC subway maps (only there for a short time in the 80s .. and who can recall their youth?) but I remember them being more "graphic" rather than "geographic". I'm thinking more of a local land projection map that would have been used for local surveying in the days prior to global GPS .. but thanks for the thought all the same!
      - theluketaylor 3y ago
        The NYC MTA map is pretty geographic by metro map standards. There are some obvious distortions, like Manhattan being wider than it actually is and it's not actually vertical as noted before. It also includes a lot of surface street and neighbourhood references. Most metro maps just focus on station names. Compared with something like the London Tube map or Paris Metro map it's extremely geographic. https://new.mta.info/map/5256 https://new.mta.info/map/5256

playworker 3y ago

Oblig: https://xkcd.com/977/ https://xkcd.com/977/

deleted 3y ago
[deleted]
nox101 3y ago
And West Wing: https://www.youtube.com/watch?v=vVX-PrBRtTY https://www.youtube.com/watch?v=vVX-PrBRtTY

jschrf 3y ago

IIRC the use of Web Mercator is primarily for ease of generating 256×256 tiles. The ideal projection is simply 3D, as it accounts for all scales, and the geoid if so inclined.

zokier 3y ago
> The ideal projection is simply 3D, as it accounts for all scales Unless you have 3D display that is not really true, it is still projected to 2D; perspective projection is still projection and it is not obvious that it's in any way "ideal" for maps
- TheBicPen 3y ago
  Sure, but it can be projected in a way that minimizes distortion of the current region you're looking at. 3D effectively allows you to choose the best projection from an infinite family of projections, while 2D restricts you to a single projection regardless of your location of interest.

orangeboats 3y ago

My personal favorite map projection is the Equal Earth projection (https://en.wikipedia.org/wiki/Equal_Earth_projection https://en.wikipedia.org/wiki/Equal_Earth_projection) but it seems like it is relatively unknown. Though in general I have a soft spot for all equal-area projects, except the abomination Gall-Peters.

taeric 3y ago

I'm assuming someone has made a graph of error versus utility in map projections? Not being able to draw straight lines is a fairly useful thing to do. If you want accurate, it is also silly to insist on it being a static 2d projection? Having a globe is not exactly difficult.

lalaithion 3y ago
A globe is just using physics to create a perspective projection on your retina. https://en.wikipedia.org/wiki/General_Perspective_projection https://en.wikipedia.org/wiki/General_Perspective_projection
- taeric 3y ago
  Right? And that isn't hard and can get you accurate images. I get that this was a lot harder in the past. But today, this isn't difficult at all.
- Retric 3y ago
  Not quite, you have two retina and local light sources. So you get more information from a globe than any 2d projection. However by rotating a perspective projection your brain can better recreate the underlying 3D nature of earth.

liotier 3y ago

To me, Kavrayskiy VII still feels like the most balanced compromise among general-purpose pseudocylindrical projection - more so than Winkel Tripel, and of course miles ahead of Mercator but that isn't even a contest.

twic 3y ago
Agreed. The only thing i have against Kavrayskiy VII is that i learned about it from the XKCD about map projections, which makes me feel like a complete fraud.

trylfthsk 3y ago

I'm partial to the Pierce Quincuncial [0] projection myself. Actually, any conformal projection that tiles really. [0]https://en.wikipedia.org/wiki/Peirce_quincuncial_projection https://en.wikipedia.org/wiki/Peirce_quincuncial_projection

contravariant 3y ago
Technically Mercator tiles.