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Thread: Map Projections

  1. #1

    Help Map Projections

    Hey,

    I've been lurking here a few years (admiring everyone's incredible maps) and I thought I'd involve myself more; I think I've got to the point I won't be embarrassed if I posted something I made in GIMP here.

    However, I usually start mapmaking with very detailed pencil drawings.

    This time, I want to, instead of just creating what is essentially a doodle (a complex and detailed doodle, sure, but still a doodle) I wnat this to be an actual map, and that means using a proper map projection.

    So the question I have here is; what's probably the best projection to use?

    Since I know there is no 'best' projection, here's what I want. I'm making a map showing an entire world (and since all the major landmasses on the world are explored and settled, it needs to include everything). There is no land under polar ice caps, which are both small, and so a little distortion at the poles is ok. But since land is quite evenly distributed between around 60 degree north and south, I don't want too much distortion going on. I'm not sure whether I want a rectangular projection or not; on one hand, I'm sure it's a lot easier to produce in GIMP or whatever, but on the other hand I really don't like how they look that much.

    Secondly; are there any programs instead of GIMP you would recommend for this kind of job? I'm ok with getting familiar with a new program if it'll help me produce a better map.

    Thanks

    Kaurne

  2. #2
    Administrator waldronate's Avatar
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    The simplest way to get the correct projection is likely to just draw directly on the correct projection template (but I think you know that). For minimal distortion, an interrupted projection would be best, but the interruptions would need to be placed so that the splits avoid land for best effect. Without knowing where your land masses are, it's hard to design a final set of projections that minimizes distortion. Much of your areas of interest are in the equatorial regions, though, which means that a reasonable whole-world compromise projection will probably do well enough.

    The Hammer projection is a relatively pleasing-looking compromise projection. Mollweide is also popular because it doesn't have the curved parallels. Any projection will work, really, as long as you have an understanding of the distortions and can deal with them. For my convenience - strike that, your convenience - I've attached some basic 15 degree grid whole-world templates for Hammer and Mollweide projections.

    Click image for larger version. 

Name:	Hammer2a.png 
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ID:	53784 Click image for larger version. 

Name:	Mollweide2a.png 
Views:	609 
Size:	583.6 KB 
ID:	53786
    Click image for larger version. 

Name:	Hammer1a.png 
Views:	762 
Size:	840.6 KB 
ID:	53785 Click image for larger version. 

Name:	Mollweide1a.png 
Views:	894 
Size:	678.8 KB 
ID:	53787

    The top row has 15 degrees lopped off each pole to avoid bunching up of the lines. The bottom line has the full ellipse for each projection. The outermost line on these is half the thickness of the others, which is an unfortunate artifact of the elderly piece of software that I used to do these.

    A tool like http://www.flexprojector.com/ will let you get a good template pretty quickly and you can design your own projections, as well.
    Last edited by waldronate; 04-20-2013 at 04:01 PM.

  3. #3
    Software Dev/Rep Hai-Etlik's Avatar
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    Besides the extent of the map, you also have to consider the purpose of the map. Different kinds of distortion are more or less appropriate depending on what the map is for. Is it a thematic (displaying a particular data set like weather or population), navigational (for getting from A to B) or reference map (For giving an overview of general information). You also need to consider the level of sophistication of the notional cartographer and the data available to them. Modern global reference maps use quite sophisticated projections that look decidedly "modern" (Winkel Tripel and Robinson in particular)

    Whatever the projection, you will have to understand the particular distortion created by it so that you can draw that distortion into the map.

  4. #4

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    Thank you for the responses!

    Quote Originally Posted by waldronate View Post
    The simplest way to get the correct projection is likely to just draw directly on the correct projection template (but I think you know that). For minimal distortion, an interrupted projection would be best, but the interruptions would need to be placed so that the splits avoid land for best effect. Without knowing where your land masses are, it's hard to design a final set of projections that minimizes distortion. Much of your areas of interest are in the equatorial regions, though, which means that a reasonable whole-world compromise projection will probably do well enough.

    The Hammer projection is a relatively pleasing-looking compromise projection. Mollweide is also popular because it doesn't have the curved parallels. Any projection will work, really, as long as you have an understanding of the distortions and can deal with them. For my convenience - strike that, your convenience - I've attached some basic 15 degree grid whole-world templates for Hammer and Mollweide projections.

    Click image for larger version. 

Name:	Hammer2a.png 
Views:	1695 
Size:	749.8 KB 
ID:	53784 Click image for larger version. 

Name:	Mollweide2a.png 
Views:	609 
Size:	583.6 KB 
ID:	53786
    Click image for larger version. 

Name:	Hammer1a.png 
Views:	762 
Size:	840.6 KB 
ID:	53785 Click image for larger version. 

Name:	Mollweide1a.png 
Views:	894 
Size:	678.8 KB 
ID:	53787

    The top row has 15 degrees lopped off each pole to avoid bunching up of the lines. The bottom line has the full ellipse for each projection. The outermost line on these is half the thickness of the others, which is an unfortunate artifact of the elderly piece of software that I used to do these.

    A tool like Flex Projector will let you get a good template pretty quickly and you can design your own projections, as well.
    I've decided on Mollweide, partly because of the nice parallel latitudes; it'll make mapping my drawing on easier. My continets also fit nicely on there; there's only a few islands in the really high latitudes. Thanks for the link; I'm trying out the tools for making my own projections; the depth is incredible.

    Quote Originally Posted by Hai-Etlik View Post
    Besides the extent of the map, you also have to consider the purpose of the map. Different kinds of distortion are more or less appropriate depending on what the map is for. Is it a thematic (displaying a particular data set like weather or population), navigational (for getting from A to B) or reference map (For giving an overview of general information). You also need to consider the level of sophistication of the notional cartographer and the data available to them. Modern global reference maps use quite sophisticated projections that look decidedly "modern" (Winkel Tripel and Robinson in particular)

    Whatever the projection, you will have to understand the particular distortion created by it so that you can draw that distortion into the map.
    Thanks for this advice; Mollweide fits, I think, for trying to display the entire world, especially the world I have where international power isn't particularly concentrated in one continent. It' meant to be a general reference map, used for naviagtion in conjuction with smaller reference maps; there aren't many huge ocean crossings in my world. Mollweide, I think, works well enough. Thanks.

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