California Dreaming – All You Need to Know About the Island of California

Have you heard the one about a massive earthquake causing California to break free from the rest of the continent and slipping into the Pacific? Did you know that early explorers and cartographers believed California was an island? The ‘island’ of California is one of the widest cartographic errors in history.

Photo of map of the Americas showing California as an island.
Novveav Continent ou Amerique by Mallet c 1685. Note California is shown as an island. (Photo own work)

The Exploration

It was the Age of Discovery and European powers were sending their ships out to chart the world. Thinking about the geography of the west coast of North America, it’s easy to understand how early explorers might have thought it was dominated by a massive island. A limited survey of the Pacific Northwest would have revealed the Puget Sound, but might not have documented its extent. Further, the Sea of Cortez, at 700 miles in length, may have been partially charted. Taken together, along with a fictional account of an island, early explorers confused Point Olympia and Baja California as the northern and southern ends, respectively, of an enormous barrier island.

Cortez, c1535, determined Baja California to be the southern tip of the island, but this was quickly disputed a matter of mere years later by de Ulloa’s subsequent exploration. Both Mercator and Ortelius correctly depicted Baja California as a peninsula.


Photo of map of the Americas showing California as an island.
Detail of California on Novveav Continent ou Amerique by Mallet c 1685. Note California is shown as an island. (Photo own work)

The legend of the Island of California no doubt had both its genesis and staying power rooted in the belief that an earthly Eden-like paradise existed–California was thought to be it, prompted by an account in a c1510 work of fiction. This seeded the idea that there was such an island in the explorers minds.

The Error

That some maps show California as an island is largely considered a cartographic error. Thinking about this, the question springs to mind: is it truly an error in the making of the maps, or do the maps accurately reflect the world as it was (erroneously) known a the time? In other words, is it a map error or an exploratory error? It turns out it is both: its origin lies in incomplete exploration, but it persisted after explorers confirmed that California was Terra Firme.

So, is was it an error? Here’s the key: if the map was made before California was widely known to be firmly attached to the continent, the map itself was not in error, but if it was made after, it was in error.

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© Peter Roehrich, 2016


A Striking Schoolgirl Map of France

In celebration of Women’s History Month, I am breaking away from comparatives in this post to examine a striking schoolgirl map. Published sometime in the 1800’s, possibly in the UK, and without doubt drawn by a child’s hand, quite likely a girl, as a study aid. Called ‘map study‘, scrutinizing and reproducing an atlas map afforded young girls the opportunity to learn geography and handwriting at a time when education for girls was limited. I hope that this early exposure to to maps and atlases inspired these girls to pursue geography as consumers of maps and atlases, as educators, and even as cartographers themselves.

Manuscript schoolgirl map of France from the 1800's.
Manuscript schoolgirl map of France from the 1800’s. (Photo: own work).

Where this map is unsigned, undated, and does not name the place it was created, we have to infer from the piece its origin. Although the subject is France, it was not likely authored in France. The markings on the map are in English, the scale in British miles, and the longitude given in degrees from the Greenwich Meridian. The map this was drawn from was likely of British origin; it stands to reason that the Paris Meridian would have been chosen as the Prime Meridian for this map were it French. Further, we can exclude the United States as the home of the underlying map for the same reason; the United States used Meridians through Washington, DC (the Capitol building, the White House, and the Naval Observatory). Provided that the underlying map is of British origin, it also stands to reason that this manuscript map was drawn in the UK.

The year in which this map was drawn is a mystery as well, but we can approximate it, or at least approximate the date the underlying map was produced. The France shown on this map is reminiscent of the post-Congress of Vienna nation. The post Napoleonic war would have no doubt triggered publication of new atlases, and to imagine an exercise in drawing these boundaries is within reason. With these in mind, this map may date to c1820.

That the map bears a trigonometric proof on verso is evidence that it was created in an educational context. From this it’s plausible that a student created it. As mentioned above, many of these manuscript maps were created by girls, and there is no immediate reason to doubt that was the case here.

Trigonometric proof on the verso of a manuscript map. This proof suggests that this map was drawn in an educational environment.
Trigonometric proof on the verso of a manuscript map. This proof suggests that this map was drawn in an educational environment. (Photo: own work.)

The evidence buried in this manuscript map tells me this is the work of a British schoolgirl about 1820. What do you think?

© Peter Roehrich, 2016

German Comparative Innovation

Comparatives were popular through most of the 19th century, published across western Europe, the United States, and later in Japan. Comparative views evolved constantly as new information became available, as publishers sought new ways to differentiate their atlases, and as new ideas in data visualization emerged. Whereas the works of European and American cartographers’ drove the changes in the genre, Humboldt, Bertuch, and Perthes were standouts as innovative German publishers of comparative views.

Black and white print c1840s of Chimborazo, inspired by Humboldt.
Physical Geography, c1840s partial reprint of Humboldt’s 1805 view of Mount Chimborazo. (Own work.)

Alexander von Humboldt shook up scientific data presentation when, in 1805, he published Geographic der Pflanzen in den Tropenlandern, ein Naturgemalde der Anden documenting his findings from his exploration of Mount Chimborazo in present day Ecuador. It was unique in that it displayed information corresponding to altitudes in relative position on a cross-section of a map. In the margins of the graphic he further annotated observations of physical phenomena and their corresponding altitudes. Where this style of visualization seems commonplace to 21st century information consumers, it was hardly such at the time; in the early 1800s visual display of data was in its infancy.

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)

Learning of Humboldt’s chart and inspired by Goethe, Friedrich Bertuch prepared his Hohen der Alten in about 1810, publishing it in his Bilderbuch, a children’s encyclopedic volume. That he published it at all, what he displayed, and that it appeared in a children’s book, are important facts. That he published it signifies the embrace of the Humboldt’s cross sectional style as a means of describing occurrences at various heights. His view took a landscape form, with mountains arranged as though viewed from afar, generally with the larger mountains to the sides and background of the image, but didn’t end there. Stick figures show Humboldt and de Suassure on Mounts Chimborazo and Blanc, respectively, a crocodile at sea level, and Gay-Lussac aloft on his record setting balloon flight. By going beyond just mountain heights to show human accomplishments, Bertuch both ties human scale and geologic scale, as well as uses the comparative as a device to showcase human accomplishment. Plants and animals appearing on the comparative pull forward the thread that Humboldt wove whereby mountains are re-imagined as not just inert monoliths, but as parts of dynamic, living systems. By including his view in a children’s book, he recognized that this genre makes complex information accessible in a simple and easy to understand format.

Print of mountain ranges arranged by height.
Perthes’s Known Heights Above Sea Level, c1855. Mountain ranges are shown one atop the next. (Own work.)

Die Benkannteren Hoehen uber der Meeres Flache in Transparenten Profilen by Perthes is unlike the other comparatives. Mountains comparatives typically show their subjects side by side in descending order or in an overlaid descending sort. Perthes, on the other hand, shows the mountains overlaid in transparency so that one can see the contours of the mountains instead of them being obstructed by the mountains in the foreground, or reduced to conic figures. This innovation is noteworthy in that it signifies an interest in the entire mountain, rather than the peak in isolation. It also represented an innovation built on the line graph, placing geographic location on the x-axis. Interestingly, and perhaps because Perthes published this as the comparative genre was at its apex, this style of comparative never took hold.

To be sure, these German cartographers (or scientist in Humboldt’s case) made great contributions to the comparative view as a style between inspiring, giving rise to, and redefining the charts. They by no means were the only innovators: Darton in 1823 produced the first compound comparative, showing both mountains and rivers in the same panel; the Society for the Diffusion of Useful Knowledge published a unique circular rivers comparative; and Mitchell was possibly the first to add comparative elements to globular projections. All told however, their pieces are testimony to the good work coming out of German cartography.

© Peter Roehrich, 2016