Random Topography Generator

How this random topography generator works

Press Generate and you get a topographic term. Mountain. Cuesta. Isthmus. Kettle. Turn up the Number box for several at once, no repeats. Copy takes them.

This is not a list of places. It is the vocabulary we use for the shapes the land makes.

Which is a stranger vocabulary than it looks, because the people who name every hill in America have officially declined to say what a hill is.

There is no official definition of a mountain

Not a loose definition. Not a contested one. None.

The United States Geological Survey, which is as close to an authority on American landforms as anything gets, states it plainly on its own website: there are no official definitions for generic terms such as mountain, hill, lake or pond.

Read that again. The body responsible for naming every hill in America has declined to say what a hill is.

This is not laziness. Try writing the definition yourself. Height above sea level fails immediately, because a five-hundred-metre bump in the Himalayas is a nuisance and a five-hundred-metre bump in Norfolk is a landmark. Height above the surrounding land fails too, because you then have to define the surrounding land. Steepness fails. Prominence helps and does not settle it.

So the USGS gave up, and it was right to.

In the United States, 121 words all mean "stream"

The USGS runs the Geographic Names Information System, the official register of every named place in the country. It has to classify them somehow, so it uses 43 feature classes, and it says outright that these are broad categories rather than definitions.

Here is what that means in practice. Every linear flowing body of water in the United States is filed as a stream. Every one. The USGS notes that at least 121 other generic terms fit that single category: creek, brook, run, kill, bayou, rivulet, fork, branch, prong, and a hundred more.

You may feel strongly that a creek flows into a river and never the other way around. The USGS has looked, and reports that no such hierarchy exists in the language.

A lake, meanwhile, is classified as a natural body of inland water, a description that fits a reservoir, a pond and a pool equally well. So the register does not distinguish them either.

Every word for a shape of land is a word people agreed on locally, and the government simply writes down what the locals call it.

Somebody made a film about this

In Britain the convention used to be that a mountain had to reach a thousand feet. Later usage moved to two thousand feet, about 610 metres, which is roughly what the Oxford English Dictionary suggests. Neither was ever law.

In 1995 a film was made from exactly this problem. The Englishman Who Went Up a Hill But Came Down a Mountain. Surveyors arrive at a Welsh village, measure the local peak, and rule that it falls just short of the threshold. The village responds by carrying earth to the summit.

It is a comedy, and it is also an entirely accurate account of what a landform definition is: a number somebody chose, which a community then has to live inside.

Three words that sound like landforms and are not

Physical geography lends the vocabulary a few words that describe something other than a shape of ground, and they are worth telling apart.

Plate. A tectonic plate is a slab of the Earth's crust tens of kilometres thick and thousands of kilometres across. You cannot see one. It is not a shape the land makes, it is the thing the land is made of, and it is moving under you at roughly the speed your fingernails grow.

Terrane. Note the spelling. It is a fragment of crust with its own geological history that has been welded onto a continent by collision. Much of western North America is a stack of terranes that arrived separately and stuck. A terrane is a biography, not a landform.

Watershed, and its twin divide. Both are lines rather than shapes. A divide is the ridge separating two river systems, and rain landing a metre either side of it ends up in different oceans. You can stand on a divide and not know it. There is nothing to see.

The land has shapes, and it also has processes and histories and boundaries. English gives all of them nouns, and the nouns look alike.

The words worth knowing

Most of this vocabulary you already have. A few are worth the price of admission.

• Cuesta. A ridge with a gentle slope on one side and a steep drop on the other, formed where tilted rock layers erode at different rates. Once you know the word you will see them everywhere.
• Kettle. A hollow left behind when a block of glacial ice, buried in sediment, finally melts. Most of the small round lakes in northern latitudes are kettles.
• Cataract. Not a waterfall. A stretch of river where the whole thing tumbles down a steep, broken bed. The Nile has six of them, numbered.
• Badland. Terrain so cut apart by erosion that soft rock has been carved into ridges and gullies and nothing much will grow. The name is a translation. French trappers called the Dakota version les mauvaises terres.
• Isthmus. A narrow strip of land joining two larger ones, with sea on both sides. Panama. Suez. Every one of them has been somebody's idea of where to dig a canal.

Ways people actually use this

• Geography revision. Generate ten and define them from memory. You will get seven.
• Worldbuilding and map drawing. Generate three and build a landscape that contains all of them. The constraint is the point.
• Vocabulary for writing. "Hill" is doing a lot of work in most prose. Escarpment, knoll, ravine and headland are all better and more specific.
• Teaching. Generate one and ask the class to draw it. The disagreements are the lesson.
• Losing an hour. Look up Cuesta. Then look up Terrane. You are welcome.

Getting more out of the filters

• Type land into Contains and you get Island, Badland, Upland, Lowland, Headland. Two describe height, one describes being surrounded by water, one describes sticking out into it.
• Set Ends with to E and you get Butte, Dune, Ravine, Ridge, Moraine, Sinkhole, Steppe, Terrace. English likes a silent E on a landform.
• Starts with C returns Canyon, Cave, Cliff, Cape, Cuesta, Cataract. Two of those you know, two you half know, and two you probably do not.
• Generate ten at once and use the results as a vocabulary quiz.

Questions people ask

What is the difference between a hill and a mountain?

Nothing official. The United States Geological Survey states that it has no definition of either, and no official feature classification standards at all. Britain has used a thousand feet and later two thousand feet, but neither was ever law.

What does topography mean?

The shape of the land surface: its heights, its slopes, its features. A topographic map shows you the shape rather than the roads.

Is a glacier a landform?

Arguably not. A glacier is a body of ice rather than a shape of ground. It leaves landforms behind: moraines, kettles, fjords. The ice is the sculptor, not the sculpture.

What is the difference between a mesa and a butte?

Size, and only size. Both are flat-topped hills with steep sides. A butte is a mesa that erosion has been working on for longer. There is no agreed point at which one becomes the other, which by now should not surprise you.

How many landforms are there?

As many as there are words for them. The US register groups everything into 43 broad classes and records at least 121 different generic terms for a stream alone. Neither number is a fact about the Earth.

References

1. What is the difference between a mountain, a hill and a peak? USGS
2. Hill, National Geographic Education