10 replies to this topic

[dekkerb]

 mapbkg.gif   6.07K   124 downloads

Does anyone know what world-projection is used in this image?
I found it on an (abandoned) Boston University site (http://duckwater.bu.edu/).
I like how Alaska and Australia aren't squashed or skewed as much as usual; though South America and Africa seam a bit off.
Can't seem to find it in any reference book or -site. Any hints in the right direction are very much appreciated!

Bart-Jan

[Hans van der Maarel]

Does anyone know what world-projection is used in this image?
I found it on an (abandoned) Boston University site (http://duckwater.bu.edu/).
I like how Alaska and Australia aren't squashed or skewed as much as usual; though South America and Africa seam a bit off.
Can't seem to find it in any reference book or -site. Any hints in the right direction are very much appreciated!

Hard to say from such a small image. The image appears to be centered at about 25 degrees East but it's not clear whether that's the central meridian or not, which makes searching for the correct match a bit awkward (most samples in books are either centered on 0 or 100 degrees West). I wouldn't even be able to confidently say whether it's a conical or azimuthal projection.

[Kalai Selvan]

I think it should be lat.lon wgs84..

 mapbkg.gif   6.07K   124 downloads

Does anyone know what world-projection is used in this image?
I found it on an (abandoned) Boston University site (http://duckwater.bu.edu/).
I like how Alaska and Australia aren't squashed or skewed as much as usual; though South America and Africa seam a bit off.
Can't seem to find it in any reference book or -site. Any hints in the right direction are very much appreciated!

Bart-Jan

[DaveB]

It's certainly projected and not just a simple lat/long geographic coordinate system. I tried a bunch of the world projected coordinate systems in ArcMap and it seems similar to Van der Grinten, but with more curvature/tilt in North America. None of the other world coordinate systems come close. It could be one that isn't included there or it could be something else entirely.

[kay]

I agree with DaveB. It is certainly projected. I have tried a bunch of world projections with MAPublisher. The closest one is Van der Grinten. That's is the only projection (so far) which can keep the shape of Greenland like this… Otherwise, it will be squished a bit… … but my van der Grinten map has a bit "thinner" South America than it is in the picture…. but van der Grinten is closest so far… :-)

p.s.- I like guessing projections :-) so much fun.

[dekkerb]

To make matters worse: it could be one of those 'interrupted' projections... Impossible to trace!
Maybe I should just try and recreate it with Bernhard Jenny's Flex Projector? Might work.

Van der Grinten - close, very close! I'll look into it.

[kay]

How about "Lagrange" map?
Take a look at those pages below:
http://members.shaw....aps/mcf0701.htm
http://www.progonos....f/projConf.html

The shape of Greenland is slightly closer to the one in your image than the one from van der Grinten...

[dekkerb]

Update!
I don't know if anybody is going to read this anymore, but a small search with google image-search (brilliant) located several other maps in this weird projection. Obviously, they use the same exact basemap, so it might be a one-off...

http://sprojects.mmi...laria-world.gif
sourced: Canada Communicable Disease Report, March 2000 (CCRD)

and
http://proceedings.e...p569/p56914.gif

[rudy]

It does look like a modified Lagrange projection but not quite: see http
://www.progonos.com/furuti/MapProj/Nor.../projConf.html


In response to this topic's subtitle: Yes. We are always right.

[M.Denil]

It is clearly neither Lagrange or Van der Gritten .
Nor is it interupted.

I first guessed it to be an old 'globular' projection of one sort or another; the name Nicolosi came to mind, but the sample on the Geocart site does not have the extent of this one. Too, globulars were pretty well restricted to one hemisphere...

[M.Denil]

The shape of Alaska is similar to a Guyou, but the example in Snyder's "Flattening the Earth" has two hemispheres and a heavily distorted western Europe.

The whole earth shape is also very similar to the Adams 'world in a square II'
link to Adams world in a square II

Of course, the sketches shown here are not very well drawn: Northern Alaska looks quite suspect, and Baffin Bay is far too round and open. In fact, the whole Canadian Archipelago is bogus: Baffin Island is squished, Devon and Ellesmere are just jokes, and the rest of the islands have nothing to do with reality at all.

The more I look at it, the more I lean towards the Adams 'world in a square II'. The parts of the world that don't match the Geocart sample are exactly the parts of suspect drawing.

Mark Denil