In just under a month, I am delighted to announce, I will be eagerly exploring the edible geography of Mexico City. The occasion is Postopolis! DF, the third in a series of events organised by Storefront for Art and Architecture. Postopolis! was launched in New York City in 2007, and it happened all over again in L.A. in 2009. I was lucky enough to attend both events as an audience member, and to be invited to participate this time is an honour indeed.

IMAGE: Postopolis! LA
The way Postopolis! works is that a handful of bloggers are invited to co-curate five days of back-to-back presentations and discussions that approach the field of urban and landscape design from as many disciplines and perspectives as possible. The list of participating blogs this year forms an impressive group: Urban Omnibus (Cassim Shepard), Intersections (Daniel Hernandez), DPR Barcelona (Ethel Baraona Pohl), Toxico Cultura (Gabriella Gomez-Mont), Tomo (Guillermo Ruiz de Teresa), Mudd Up! (Jace Clayton a.k.a DJ /rupture), We Make Money Not Art (Regine Debatty), Strangeharvest (Sam Jacob), and Wayne & Wax (Wayne Marshall).
Together, we’re putting together a list of speakers that ranges from government officials to DJs, academics to urban farmers, and waste disposal experts to documentary filmmakers—via a healthy sprinkling of artists, architects, and designers.

IMAGE: The courtyard at El Eco.
The five-day marathon will take place from 4 p.m. onwards between Tuesday, June 8, and Saturday, June 12, at the Museo Experimental El Eco in the Reforma Avenue neighbourhood of Mexico City. It is completely free and open to the public, the talks will be conducted in either Spanish or English, with simultaneous translations available, and each day will end with an after-party hosted by local music blogs. Rumour has it, the entire event will be streamed live online—I’ll confirm that nearer the time.

IMAGE: Clockwise: street food, the Bordo de Xochiaca dump, chinampas, and Mexican refrigerated trucks waiting to cross into the U.S.
Mexico, and Mexico City itself, offer a huge amount to discuss in terms of edible geography, from the chinampa system and the wheat and maize research of CIMMYT, to a fabulous diversity of street food and the U.S. FDA’s overseas expansion. Although the full speaker list and schedule is yet to be confirmed, Postopolis! DF is shaping up to be a pretty interesting event, and I definitely hope to see some of you there.
Meanwhile, since this is my first visit to Mexico City in more than a decade, what should I make sure to see and eat? Any tips or suggestions would be gratefully received.
Postopolis! DF is organised by Storefront for Art and Architecture, and presented in partnership with El Eco, Tomo, and Domus. Additional sponsors include Mexicana, the British Embassy, Urbi VidaResidencial, UNAM, Difusión Cultural UNAM, Cityexpress, and XXLager. Thanks also to Joseph Grima, Daniel Perlin, César Cotta, José Esparza, and Blog Non Stop.






























































Sixty-Six Percent Natural
IMAGE: Screen grab showing global agricultural land-use in 1700, from World Cropland, Bill Rankin, 2009.
At Bill Rankin’s fantastic Radical Cartography site you can see an animation that shows the intensification and spread of agricultural land-use around the world over the past three hundred years.
IMAGES: Screen grabs showing global agricultural land-use in 1750 and 1800, from World Cropland, Bill Rankin, 2009.
I could spend hours with these maps: for example, it’s amazing to see that agricultural activity in India in 1700 is as intensive, if not more so, than in the traditional bread-baskets of the Caucasus or the densely populated areas of Northern Europe. The persistent un-farmed patch of France’s Massif Central is also interesting: even the Alps appear to have more agricultural activity.
IMAGES: Screen grabs showing global agricultural land-use in 1850 and 1900, from World Cropland, Bill Rankin, 2009.
Rankin notes that the major trend of the past three hundred years is simply the intensification of farming practices on land that was already agricultural, “punctuated by several episodes of rapid expansion into previously untapped areas: the Great Plains in the late nineteenth century, Argentina in the early twentieth century, and in last few decades, Brazil and central India.” He also points out rare but occasional declines in agricultural density: in the “central Amazon, northern Patagonia, or the Appalachian Piedmont after World War II.”
IMAGES: Screen grabs showing global agricultural land-use in 1950 and 1992, from World Cropland, Bill Rankin, 2009.
You might be wondering how Rankin knows what percentage of land was used for growing crops in 1700, before much of the world had even been charted, let alone systematically analysed in terms of land-use.
The dataset on which Rankin’s animation is based was developed by Navin Ramankutty and Jonathan Foley, whose methodology relied on an assessment of global agricultural land in 1992, at “5 min spatial resolution” (about 10 km at the equator), by “calibrating a remotely sensed land cover classification data set against cropland inventory data.” They then compiled an “extensive database of historical cropland inventory data, at the national and subnational level, from a variety of sources,” and processed that information through their 1992 land cover/inventory algorithm, in order to arrive at a historical reconstruction.
As Ramankutty and Foley freely acknowledge, the resulting map is a guess, albeit an extremely educated one that also matches what we know of “the history of human settlement and patterns of economic development.”
As always, much of the interest in maps like these lies in thinking about what is or isn’t measured—and why. Personally, I’m intrigued by the intensification metric, and the visual implication, as Bill Rankin puts it, that “many agricultural areas are at close to 100% exploitation.” This doesn’t seem quite right: Ramankutty and Foley are measuring agricultural land use (and only at a resolution of about 10 km at the equator), not productive potential. After all, surely an area of land could be solely devoted to agriculture and yet produce wildly differing yields depending on the crops sown and the farming techniques used?
IMAGE: Map showing the suitability of land for agriculture. The map (larger view here) is derived from more data sets developed by Ramankutty and Foley, available at the Atlas of the Biosphere.
Elsewhere, Ramankutty and Foley have also collaborated to map agricultural potential, based on “the temperature and soil conditions of each grid cell.” Somewhat implausibly, since agriculture both shapes and is shaped by human civilisation, the suitability rating ignores human inputs—urban sprawl, artificial irrigation, topsoil creation—altogether.
Stepping even further away from plausibility (and human intervention), Ramankutty and Foley subsequently produced a fascinating map of potential vegetation, showing “the vegetation that would exist at a given location had human forms of land use never existed.”
IMAGE: Map of potential vegetation. The map (larger view here) is derived from more data sets developed by Ramankutty and Foley, available at the Atlas of the Biosphere.
It is an alternate surface of the earth, carefully surveyed and classified by a human civilization that could not have existed in order for it to be a reality.
On a similar note, Colorado State University researcher David Theobald has designed a new system for evaluating and mapping the “naturalness” of a landscape. In his review, Rob Goldstein describes Theobald’s methodology thus:
Using this technique, Theobald arrived at “a natural landscape score of .6621 for the conterminous United States in 2001.” In other words, the lower forty-eight states are sixty-six percent “natural,” and only one-third human-designed, or “unnatural.”
The project seems flawed on several levels (it is somewhat incredible that Owens Valley, with its hijacked river and poisonous lake-bed, could receive the “highest naturalness” scores under any rubric), but the paradox of its premise is fascinating—that a pure form of nature can be carefully located and recognised as such by humans whose activity otherwise renders impossible its very existence.
Theobald suggests that his system is a useful tool for conservationists seeking to prioritise their efforts. To me, however, it is more interesting as a geographic expression of impossible nostalgia—the land-use database equivalent of medieval monks calculating how many angels could dance on a pin.
[NOTE: Thanks to @agrobiodiverse for the link to Rob Goldstein's piece on David Theobald's system.]