View Full Version : Help With Proper River Positions...(Embarrassing I know)

The Doge
01-12-2013, 12:39 PM
Hello everyone. I hope that you are all well.

So, I've been working on a map for my about a year-and-a-half or so and I am very nearly finished (with the design anyway. I have negligible skills with the GIMP or Photoshop...so I'm kind of at a sticking point as far as the actual quality of the map is concerned.)
My greatest remaining issue is the fact that it has been brought to my attention (by noted Guild Member Sapiento) that several of my rivers were placed erroneously.

Determined to solve the issue myself, I read over Redrobes' tutorial on river placement (http://www.cartographersguild.com/tutorials-how/3822-how-get-your-rivers-right-place.html) and promptly realized that I couldn't for the life of me see where the problems were on my map. I just can't seem to actually process the information in the tutorial, though it seems easy enough.

So, fellow guildmembers, I have attached two versions of my map below, one with the rivers and one without. I would appreciate it greatly if you could all point out to me any errors that I have made. If I can have nothing else in my map...I at least want my rivers to be in the right spot! :lol:

Thanks to you all in advance. I would be greatly appreciative of any help.
The Full Map

The Map with all Rivers Removed

- Max -
01-12-2013, 12:48 PM
Hi THe Dodge. Rivers (in most of cases) used to start in moutains and flow down towards oceans which isn't the case of a lot of them on your map it seems. At least it doesn"t appears clearly on it.

01-12-2013, 01:59 PM
What is the scale of the map (that is, how big are some of the prominent features)? The amount of land area visible will have a big impact on the number and size of rivers that you have.

Also, you have a lot of mountains, suggesting that this map covers a large area. The more mountain ranges between the sea and a land area, the less rainfall will make it to the area; this lack of rainfall usually translates to a reduced number of rivers in an area.

http://www.cartographersguild.com/tutorials-how/3822-how-get-your-rivers-right-place.html is the popular discussion area for this topic. Try reading through that and see if it makes sense.

There is really only one rule for rivers, though: water flow downhill until it evaporates, until it sinks into the ground, or until it pools into a pond, lake, or sea. Everything else is derived from that one rule (and the context in which the water is doing the flowing, of course).

The Doge
01-13-2013, 08:00 AM
Thanks for the replies.
Max: Are my rivers having problems concerning their end or their origin? I tried to have most of them spring from mountains...though I'm not sure if I was successful even in that regard.

Waldronate:Thanks for the tips! As I said in the OP, I read 'How to Get Your Rivers in the Right Place', but it didn't help me much. Partly because I have no idea how to make a terrain height map like he did. I lack artistic ability or even a basic grasp of GIMP or PS skills...would you have any idea how to reproduce his effects in Paint.net or GIMP?

Thanks again to both of you!

- Max -
01-13-2013, 08:10 AM
Well Im not an expert but for example : the 2 group of rivers in the southern area, above the big peninsula seems weird like they start and end in mountains. Maybe having more terrain geography besides mountains and rivers will help a bit...

01-13-2013, 09:50 PM
Redrobes' info is great, but if you're not getting it from the tutorial, let me try some different words. First off, is maybe a component of your troubles an inability to imagine 3-d views in your mind's eye? If you can, that makes imagining which way is downhill easier. If not, you'll have to use more rules of thumb and generalizations.

Some of those rules:

Figure almost every stream is going to wind up as a river entering the sea. Imagine some of those little short riverlets you show as looking around for "a way further down". If there truly is no lower land nearby, well that water and all his friends are going to hang around and party - call that a lake - until the crowd gets so big that the outer edge gets above the rim of the local lowland, and starts to flow again.

Yup, there are streams that disappear, either by ducking underground and continuing to flow, or by fizzling out into an arid wasteland. Those are pretty rare special cases, so for believability's sake avoid them unless a specific story line calls for them.

Another good general rule- rivers don't split. They join. At the scale of continental map you have, it'll be a rare case for there to even be a brief divergence visible that you'd call an island; any such multipath watercourses - termed threaded streams- are going to be within the width of the line you use to show a river. You definitely don't see such splits as your westernmost river, where you show two widely divergent ways to the sea. Using that particular river I can illustrate another placement generality -- that inlet is there because it's lower than the two peninsulas that you have water running along the length of. Figure the peninsulas must be ridges, at least generally. So you would expect water to "fall off to the side" of both of them instead of running the long way down the middle. Which is incidentally why someone asked you about scale - if those are about the size of the whole Spain + Portugal peninsula, okay, I'll buy there being enough room for slightly higher land on the north and south edges, "channeling" the water out toward the tip. If the scale is more like those are ten miles across or even a hundred, my instincts are to not buy it. Viewers don't do all this analysis, they just instinctively feel something is right or isn't. Some of course being clueless, some having a vague discomfort, and some experiencing the same sensation as fingernails on a chalkboard. I'm in the latter camp. That's because I do have a bit of a 3D picture even just based on your coastline, so those two river courses west of the split look to me like they're literally running along ridgetops.

The smaller one just south of that major divergence also shouldn't split, but I'll use it to illustrate another generality: water insisting on flowing downhill means you'll never see it flowing *across* a hill. Now if your scale is small enough ("smaller scale equals bigger area shown" is a mnemonic) there could be a valley across the foothills of that range. But the generality would be for us to expect the overall slope at any point to be away from the pictured mountains straight toward the nearest coast. So if you need a river to skirt that range just so, you want to indicate foothills or something to push water back toward the steep mountains.

01-13-2013, 10:13 PM
So here I am blathering about all these landform shapes I "see", even though all you drew were the highest mountains. How? And how can you learn to see it? At the most basic, you've depicted highest and flattest. You know how to see topography shapes based on contours? Can you? Even without a crazy-intricate set of contour lines, look at a map with a well-defined set of (plausible) rivers. That net of lines indicates all the locally-lowest spots. The blanks *between* the river lines show a set of ridges. On steep terrain, sharp ridges. In flatter terrain, low mounds or barely-discern able rolling swells.

Further clues to the land can be inferred from how tightly packed the lines of the river net are. Sparse looks a little flatter and/or drier. Since you're making this world, you can decide how small of a stream you'll show. Continental maps won't depict down to inch-wide rivulets. Rather you might stick to only the parts of various branches that are navigable... Whether by rowboat or by steamboat or by supertanker is up to you. Face it, way up in the mountains all the streams will be pretty small. At most sketch a few of those in - maybe just the ones watering settlements or defining borders.

Rivers don't typically just flow *into* mountains. But they might pass *through* mountains or other high land. Maybe a pass or a water gap or a canyon permits a low enough passage for flow.

01-13-2013, 11:33 PM
Deltas: a special case, against the no-dividing generality. See, the land part of a delta is pretty much flat as flat can be, as is the water in all the confused tangle of passages. As a teeny bit more sediment is dropped *here* this channel becomes temporarily higher, and more water flows over *there*. Which erodes this bank, curves that meander more, cuts off yonder passage entirely, and bang! New Orleans is no longer a major port. Or would not be, betimes, if the lower Mississippi were left alone. Dredges and dikes fight the current, and put water where mankind wants it- till the next flood, when the river asserts itself and human commerce stages a strategic withdrawal.

Don't think of a delta as what some rivers do before they reach a coast. Instead think of them as what can happen after river water *passes* a coast (lake too, not just ocean). Restricted flow spreads out when the banks are left behind, slows, and drops megatons of sediment. So unless a river lets out into a bay (certainly does happen), figure a delta as sticking outward, not extending ashore.

A river could do a similar thing as it reaches a dry lakebed; spreading out into multiple threads and dropping sediment. That's an alluvial fan - small-scale seen at the base of any steepish mountain. Large-scale you could see such at the edge of a desert (death of a river, a bit rare), or (with water flow continuing on through) any well-watered transition from steep to flat.

Say a river rushes down out of the mountains and hills, and fins itself traversing flat terrain. The flatness could be the river's own fault, after it filled in some steeper sided valley with sediment over the years. In flatter surroundings is when a river will tend to meander. Mind you, headwaters can be crooked, being at the mercy of however valleys intersect. But on the plains or in broad river valleys one year *this* way is temporarily "most down" (maybe by a matter of inches of altitude) and a couple of years later sedimentation and the erosion of banks makes *that* way a little lower. Thus the smooth loops and elbows of the lower Mississippi (and Amazon, and Rhine, and Yangtze...). Draw a river doing that, and you've shown me the land is flat.

Tributaries will be missing if the land a river passes through is dry (see the lower Nile). Lots of rain, then more tributaries - but you needn't show the thick nets you do in some way-upstream headwaters.

Where will there be more or less rain? Oooooh, big subject. A whole series of college courses in fact. A browser and a curious mind will garner enough generalities to achieve decent plausibility though. Think of humidity as being scraped off of passing air masses when crossing mountains. Thus Middles of big continents tend to be drier. By air movement, here we mean prevailing winds, thus you can get wet seasons and dry ones as summer and winter shift all the general highs and lows around. If you don't want to get too detailed, just claim your prevailing winds are like thus-and-so, and written the areas upwind of mountain ranges, and dry out the downwind "rain shadows". All other things being equal, coastal land will be at least somewhat damp - the N African coast and the Namib and Atacama deserts being exceptions based on wind patterns.

01-14-2013, 02:45 AM
Literally ran out of battery on my phone there:-). If those thoughts don't give you ideas on bettering your existing river routes, holler and I'll comment on more specific ones.

The Doge
01-14-2013, 08:24 AM
Thanks for the comments Jbgibson. There's some excellent advice here. I'm going to take a stab at reworking the rivers with that in mind and I'll post the results here for your opinions. Stay tuned :D
Thanks again everyone. It's advice like this that inspired me to join this forum.

01-14-2013, 10:58 AM
Waldronate:Thanks for the tips! As I said in the OP, I read 'How to Get Your Rivers in the Right Place', but it didn't help me much. Partly because I have no idea how to make a terrain height map like he did. I lack artistic ability or even a basic grasp of GIMP or PS skills...would you have any idea how to reproduce his effects in Paint.net or GIMP?

Reading comprehension has rarely been something of which I am accused. I didn't notice the reference to the tutorial was already in your post.

You've identified mountains, and that's the hard part. Now just identify some low spots (the ocean and your lakes should be those spots). Now draw lines from high to low, going over the shortest distance possible without going from low to high. If you can identify some intermediate levels of low-to-high, things will get easier.

I am especially gifted in the lack of artistic ability department. To make up for that lack a little, I do write some software. http://www.cartographersguild.com/attachments/mapping-challenge-archive/43488d1333086525-march-april-2012-lite-challenge-entry-csu-johnsondales-new-found-lands-ink-blots-islands-using-wilbur.pdf describes a process that can generate fairly plausible rivers with very little in the way of artistic input (if you can paint white blobs on a black background, you can use this process). It takes some CPU power, memory, and a copy of MS Windows among other things.

01-14-2013, 11:13 AM
JBpedia :D
He helped me a lots in my river's position in my map.
Here is a crude view of your topography (worked as good exercise for me)

The Doge
01-14-2013, 04:28 PM
Obrigado Aquarits!

And thanks for the tip Waldronate. I think that I'm getting the hang of things now.

01-14-2013, 05:28 PM
I learned a lots with this topic.

And thanks for the "Obrigado" :D:D