Thread: Feedback Requested for First Map

Hi there Rambledmind, welcome to the Guild! Well I'm not one of the river police (so I might be wrong), but I think the mountain and river placement look pretty good (though I'm not sure if the long river in the North-Eastern continent would realistically survive the heat of that large of a desert). Is there some sort of story behind the lava lake (I assume that's what it is) in the small central continent?

Cheers,
-Arsheesh

To beat Hai-Etlik: if your map is equirectangular (and it looks like it is) than the south pole would be mapped to the complete lower edge of the map and your pseudo Antarctica has to be stretched along the lower part of the map. Just compare it to some maps of Earth, like here: http://en.wikipedia.org/wiki/Equirectangular_projection.

Originally Posted by cfds

To beat Hai-Etlik: if your map is equirectangular (and it looks like it is) than the south pole would be mapped to the complete lower edge of the map and your pseudo Antarctica has to be stretched along the lower part of the map. Just compare it to some maps of Earth, like here: http://en.wikipedia.org/wiki/Equirectangular_projection.

A few other points:

This projection produces distinctive and unattractive distortion. Drawing the parallels all be the same length means higher latitudes get progressively more an more stretched out. If you draw things on the map without that distortion, it means you have drawn the land itself with the opposite distortion to compensate. So the land is all "pinched" together toward the poles.

The scale bar is also inappropriate. The scale varies depending on the latitude and the direction (This is an issue for and projection, the only way around it is to restrict the extent of the map) In case you were considering adding one, a compass rose would also be inappropriate as compass bearings vary with latitude too. (The Mercator projection is the only one that preserves bearings over a global extent)

This projection is rarely used for reference maps. It's ugly and doesn't preserve area or angles. It is sometimes used for thematic maps, though equal area projections tend to be better for that, and it's useful for source data that is going to be manipulated in certain ways (mapping onto a 3D sphere or converting to other projections for instance) though you want to avoid labels, textures, and fancy symbolization in that case as they will be distorted.

Originally Posted by arsheesh

Is there some sort of story behind the lava lake (I assume that's what it is) in the small central continent?

That's what it's supposed to be. I'm working on the texture around the lava, still, but it's getting there. There is a story behind it involving an angry god and a meteor, causing a crater, then a little liberal use of the fantasy setting to lead it all the way down into the depths, allowing lava to come bubbling up into a lake.

Also, I'm trying to get a Nile feel from the long river in the North-East continent. I may need to work in a few more tributaries to keep it going.

Thanks, everyone, for all of the great feedback! I did make it equirectangular, but I didn't fully understand what that meant. My goal was to create a map that would allow me to simply crop out regional maps, maintaining scale throughout. Is there any projection that would actually do that? It seems like I may have to do the regional portions and work back into a world view. Most of my stories will take place in the area in the North-West, but I wanted to get it all out there to maintain consistency as the stories (hopefully) continue to grow.

Thanks again for the feedback. It's exactly what I was hoping to learn here!

Originally Posted by rambledmind

I did make it equirectangular, but I didn't fully understand what that meant. My goal was to create a map that would allow me to simply crop out regional maps, maintaining scale throughout.

The simple answer is "no"

Mapping from a sphere (planet) to a rectangular map will create distortion, for the same reason you can;t take an orange peel and flatten it out into a rectangle. Projection can preserver one or more (but not all) of:
* Area
* Shape
* Direction
* Bearing
* Distance
* Scale

http://en.wikipedia.org/wiki/Map_projection

For example, the equirectangular is great around the equator, but pinches the poles when used in the fashion you created your map, as distance is not preserved. (And to have a scale bar on such a projection makes no sense at all). here is your map:


-Rob A>

That makes sense. I'll have to crop them out into regional maps and work backwards to some sort of world view after I read up on the different projections. Thanks for the explanation!

Originally Posted by RobA

The simple answer is "no"

Mapping from a sphere (planet) to a rectangular map will create distortion, for the same reason you can;t take an orange peel and flatten it out into a rectangle. Projection can preserver one or more (but not all) of:
* Area
* Shape
* Direction
* Bearing
* Distance
* Scale

http://en.wikipedia.org/wiki/Map_projection

For example, the equirectangular is great around the equator, but pinches the poles when used in the fashion you created your map, as distance is not preserved. (And to have a scale bar on such a projection makes no sense at all). here is your map:


-Rob A>

Actually no projection can preserve linear scale/distance in general over a large extent and it's not just rectangular maps (Cylindrical Projections), any projection of the curved sphere onto a flat plane produces distortion. You can preserve Angles (Conformal), Areas (Equivalent/Equal Area), or distances along great circles through a particular pair of antipodal points (Equidistant). Only one projection preserves bearings, and that's Normal Mercator (Which requires that it be Conformal as well). A few other projections preserve other interesting properties (Gnomonic maps all great circles onto straight lines, Stereographic maps all circles onto circles).

This projection is equidistant for distances along arcs of great circles through the poles, which is why it is also called Equidistant Cylindrical.

Over a small extent, as long as the projection is appropriate to the extent, linear scale, area, and bearing should all be pretty close to true. This is one of the reasons you can't just crop out sections and scale them up. Maps of smaller extents need projections appropriate to those extents. You can sort of do it with Mercator as it sort of preserves shapes, but it has problems at intermediate scales like continents (This is what most zoomable web maps do) and you need to use a special formula to figure out the effective scale at a particular latitude. It also falls apart at the poles.