Cowperthwaite

Sorting from largest to smallest is an easy way to arrange objects; a gradient sort is efficient and boring. More interesting is a pyramid sort; for a mountains comparative view, the shape of the sorted objects mimics the shape of the objects themselves. The shortcoming of the pyramid sort (and of the gradient sort) is in the amount of space it occupies. Overlaying smaller mountains on top of the larger ones in a pyramid fashion yields a tight, sorted set.

Heights of Mountains and Lengths of Rivers, Cowperthwaite, c1850. (Photo own work)
Heights of Mountains and Lengths of Rivers, Cowperthwaite, c1850. (Photo own work)

Finley, in 1827, published the first mountains comparative with an overlaid pyramid sort. Some ten years later, Tanner merged the mountains and rivers compound comparative style with the Finley’ mountain sort. In his work, the mountains were centered, the eye immediately drawn to the tallest, and the rivers were arranged in an inverted trough sort to compliment the mountains with the longer rivers on the edges. By 1850 at least two other cartographers, Mitchell and Cowperthwaite, published the same plate, a testament to its design elegance.

His work was not without flaws. The design pointed to the tallest peak, Dwahalagiri (Everest was ten years away from being surveyed), with the smaller peaks hidden in plain sight. Moreover, he left the middle of the mountains exhibit wide open, wasting space that could have displayed mountains from intermediate height ranges. His exhibit shows 151 mountains and volcanoes, about 25% fewer than the other mountains and rivers comparative maps of the day.

Taken together, flaws and all, this work is beautiful and elegantly uses space. An innovative arrangement for a comparative view, this chart no doubt influenced other comparative maps for decades to follow.

Want to learn more about comparative maps? Check out my free ebook!

© Peter Roehrich, 2016

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What’s in a Name?

What’s in a name? What does it mean for a map to be titled a comparative? It’s been a while since I discussed the fundamentals of comparatives; this post reviews those but is by no means exhaustive.

I have developed a few criteria for comparative views. Comparative views must be: continuous depictions of geographic features, arranged by size (with a few exceptions), to show variation in size with an accurate scale, and usually have a human scale benchmark.

Possibly the first comparative view of the early style, showing mountains of the old and new worlds.(Own work)
Hohen der Alten by Bertuch, c1810. Possibly the first comparative view of the early style, showing mountains of the old and new worlds. (Own work)

A Brief History
Comparative views were inspired by Humboldt’s 1805 chart. Although it wasn’t a comparative, it planted the seed for visual display of altitude related data visually. Bertuch was the first to widely publish a comparative, c1810, in the form of a fictionalized landscape. This style gave way to the stylized graph format seen in most comparatives, often found in atlases. By the late 19th century comparative views had fallen out of favor.

Principal Mountains by Carey and Lea, 1832. This miniature map of mountains shows pyramids as a human scale benchmark.
Principal Mountains by Carey and Lea, 1832. This miniature map of mountains shows pyramids as a human scale benchmark. (Photo: own work)

Continuous
Comparatives must give the illusion of looking at a scene or “view” of geographic features. The first comparatives did this by taking the form of a landscape. Later comparatives, those of the graph style, achieved this through abstract means where the peripheral attributes of one feature blended into another; mountains slightly overlapped to form a range and rivers drained into a common body of water. Without this unity among the features, the comparison would hardly exist as it would be district images, not inviting the reader to compare them.

Five panel lithograph mountains and rivers comparative view.
Five panel comparative chart of mountains and rivers by Johnson. Note the graph like style, where mountains are simple cones. c1855. (Photo: Own work)

Arrangement and Scale 
A comparative view is a device to highlight the large (usually, although as always, there are exceptions) mountains, rivers, etc., of the world. As such, they must be laid out so that the reader can readily identify the largest of the objects. Employing (usually) a sorting methodology achieves this. Sorting so as to create a gradient, largest to smallest or vice versa, is common. Pyramid sorting is common with mountains, placing the largest mountain in the middle and the smaller ones to the sides, alternating. Scaling objects on a similar basis is essential to allow readers to evaluate their relative sizes.

The Great Pyramids and Paris as shown on Thomson & Lizars' A Comparative View.
The Great Pyramids and Paris as shown on Thomson & Lizars’ A Comparative View. The Great Pyramids serve as a human scale benchmark. (Photo: own work)

Human Scale Benchmark
Heights of very large objects like mountains are hardly meaningful without something of a translation. That translation is achieved through a benchmark that is an intermediary. Many comparatives use the Great Pyramids of Giza as such an intermediary; albeit large, pyramids are still on the human scale to the extent that they were built by hand, people can easily walk around them, and they can be scaled. Despite being on a familiar scale, their size is substantial enough to be compared to mountains.

More
Check out some of the great resources from David Rumsey, Geographicus, and Hautdidier.

© Peter Roehrich, 2016

Styles of Comparing Rivers

I am pleased to add two new comparatives to my collection: A Map of the Principal Rivers shewing their Courses, Countries, and Comparative Lengths by the Society for the Diffusion of Useful Knowledge (SDUK)

Principal Rivers by SDUK, 1834. Rivers shown by direction of flow emptying into central sea. (Own work)
Principal Rivers by SDUK, 1834. Rivers shown by direction of flow emptying into central sea. (Own work)

and
Comparative Lengths of the Principal Rivers Throughout the World by Fielding Lucas,

Comparative Lengths of the Principal Rivers of the World by Lucas, 1823. (Own work)
Comparative Lengths of the Principal Rivers of the World by Lucas, 1823. (Own work)

of 1834 and 1823, respectively.

Lucas’ Comparative Lengths… is a very ‘conventional’ rivers comparative, where the rivers are shown sorted by continent, then by length, all draining into a representative body of water on the left. Of note is that the longest rivers of the Americas wrap, while the longest river of Africa is shown interrupted and truncated. What is to be gleaned from this? We can surmise that this is a matter of the author’s perception, right or wrong, that the rivers on this map of primary interest to the reader were those of the Americas, specifically the US. This map was clearly intended for a US audience and was published in Baltimore, MD. The treatment of the Congo & Niger as both interrupted and truncated tells the reader to be aware that there are long rivers in Africa, that the territory is unexplored, and that in the author’s mind they are of secondary importance.

American Rivers on Lucas' 'Comparative Lenghts'. (Own work)
American Rivers on Lucas’ ‘Comparative Lenghts’. (Own work)
African Rivers on Lucas' 'Comparative Lenghts'. (Own work)
African Rivers on Lucas’ ‘Comparative Lenghts’. (Own work)

In contrast to the above, the A Map of Principal Rivers … by SDUK is abstract and even surreal, even by the standards of comparative maps. It has an unusual sort, from my analysis it is sorted by the direction it drains, then by size. Interestingly, it shows all rivers emptying into a central water body. This might reflect an effort to highlight the interconnectedness of waterways. Further evidencing this is the inclusion of inland bodies of water, like Lake Michigan pictured with the St Lawrence, which are usually not shown on rivers comparative views. Alternatively, to focus on Lake Michigan, the inclusion of such a body might simply be a reflection of SDUK’s mission to provide the working class with scientific knowledge. Where Chicago was rapidly emerging as a center of industry in the early 1800s, it no doubt would have had a large working class who would have benefited from having a local point of reference. That said, SDUK was a British organization and their consideration of or distribution to American readers is unknown to me. Note that Lake Michigan is shown as straight rather than curved, as I’ve previously discussed (same engraver).

Nile detail of Principal Rivers by SDUK. (Own work)
Nile detail of Principal Rivers by SDUK. (Own work)
Great Lakes detail of Principal Rivers by SDUK. (Own work)
Great Lakes detail of Principal Rivers by SDUK. (Own work)
Central sea detail of Principal Rivers by SDUK. (Own work)
Central sea detail of Principal Rivers by SDUK. (Own work)

These lovely comparatives, one simple and one ornate, can tell us as much about their intended readers as they can about the understanding of the world at the time.

© Peter Roehrich, 2015