Making Regional Maps of a World Map

[su_liam]

there is no real way around the technical issues of remapping
i would have posted about MMPS ( or ISIS_3 that i normally use) and not Wilbur
but then i use the terminal for a LOT of things

I would love to see a tutorial on MMPS, even more so for ISIS3, with which I have no experience.

One obvious advantage of MMPS, at least, is that you could work with projections. With Wilbur, you'd be working strictly with latlong or blowing up a patch of a predetermined coordinate system. Re projection would have to be done separately, and many of the simpler apps for reprojecting maps assume a full globe equirectangular image. Problematic, that.

[Vidgange]

Wouldn't Morikahn's suggestion mean you get a lot of distortion when making a regional map? Looking at a regional map of Europe you notice it's often a bit different from Europe on a world map, no?

[johnvanvliet]

yes there would .
but the map in the first post is not really map projected

it looks to be some what in a almost Mercator projection ( almost)

using the Earth is a good example -- people know what it looks like
three different projections for the SAME bit of land - North America ( i live in Michigan )
85 North to 10 North
-170 West to -10 West
all 3 are at 16 pixels per degree

-- Simple Cylindrical --


-- Mercator --


-- Polar Stereographic --



for some reason i have noticed a LOT of squarish maps that are not in Mercator but look to be almost but not quite in Simple Cylindrical ,but some cross in between .

[Darce]

Great information here. Glad I joined. I have one question on the world map sizing and making smaller detailed maps. I am planning to use Ascension's tutorial which has a square canvas. Would a rectangle canvas better represent the oblate ellipsoid that Earth is when creating our own fantasy world? Will I cause more problems using G.Project or other tools?

[Azélor]

Great information here. Glad I joined. I have one question on the world map sizing and making smaller detailed maps. I am planning to use Ascension's tutorial which has a square canvas. Would a rectangle canvas better represent the oblate ellipsoid that Earth is when creating our own fantasy world? Will I cause more problems using G.Project or other tools?

It is better to use an equirectangulatr map (aka platte carré) at a 2 for 1 ration. Most softwares use this as their default projection so you can project it to another projection later.

[Darce]

It is better to use an equirectangulatr map (aka platte carré) at a 2 for 1 ration. Most software use this as their default projection so you can project it to another projection later.

Great information. I tried the 1:1.6182 Golden Ration approach, but I see I put too much though into it.

[johnvanvliet]

the 2 x 1 comes from there being 360 degrees Longitude ( east / west ) and 180 degrees latitude ( north / south )

also computers are "binary " they REALLY like things in multiples of two
( 2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,163 14,32768,65535,....)

so most software works best if the image is also a "multiple of two"
( NOT a stead fast rule( most of the time) but just a good idea to use -- IF possible )

i tend to make images that are
4096x2048 px
8192x4096 px
16384x8192 px
or HUGE ( 131072 x 65536 px )