Cartodynamism

Herodotus laid down his world on parchment with ink. Samuel de Champlain traveled with paper and pencil. They - and every mapmaker in between and since - created map objects that were imbued with authority.

Maps have always been trusted for complex reasons; social, cultural, political. But for millennia map-making and even map-reading were the province of an elite few, mirroring the dynamic of priests who owned the word of god when the world was 5% literate. Only in our great-grandparents' lifetimes have maps been democratized, their use become common for road navigation and capital-memorizing.

Broken Survey - Incomplete topography in Wyoming


The same way it shook everything else in our lives, the internet has brought maps a step further. Common map interfaces are available in every browser and show only the most basic of facades - these maps contain the world within, and the whole of geography in a 4"x3" container on a glowing screen. Cartographers are only just starting to grasp the possibilities here - this technology isn't yet a decade old - but now that maps of everything are available to everyone, the size of the world has changed.

Washington D.C. live - dark dynamic cartography

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Multi-Attribute Labels in QGIS

We frequently have to render feature labels on maps that have more than one type of information in them, for instance both parcel ID and parcel area. This quick run-through shows the process for multi-attribute labelling in QGIS, eveyone's favorite open-source alternative to ArcMap.

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Agriculture, Food and Poverty

A recent post from the world of crowdsourced mapping has me thinking about food availability and the nature of poverty in the United States.  The Brooklyn Food Coalition has begun a community food survey, collecting location and stocking information for food stores throughout the borough.  The aim is partly to identify zones where - for reasons of distance, transportation or pricing - it is difficult to locate healthy food.

The general term used to describe zones like these throughout the country is "Food Deserts."  This also refers to the economic state of people; a household is said to live in a food desert if it doesn't have access to a car or public transportation, and lives more than a mile from a grocery store.  According to the USDA, there were 2.3 million such households in 2009.  Here's what that looks like spatially, broken down by county:

Percent of households a.) without access to a car, and b.) living more than one mile from a grocery store (Data: USDA)

While there's lots of local variation, the emerging theme is one where relative poverty and food deserts coincide spatially, particularly in the South and in Appalachia.  Huge chunks of rural America lack access to fresh foods, relying instead on smaller stores with a greater abundance of processed foods.  The Brooklyn Food Coalition is also noting this trend on the community scale, and with greater detail about the specific character of food availability.

There is a dichotomy here, and it will require further investigation: How do food deserts line up spatially with agricultural production?  Here is a tiny look in that direction, using a geographically-weighted regression:

Percent of county land area in crop cultivation (Data: NASA)

And what I'll call the "Map of Socio-Agricultural Irony", or where existing food deserts coincide with high levels of total crop cultivation:

Geographically-weighted local R-squared: percent area in cultivation vs. percent of population in a food desert per county

Amber waves of grain everywhere, and not a kernel to gnaw on . . .

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Political Space

As the dust settles following the 2010 midterm elections, we're back to agonizing over the political nature of spatial relationships.  Both sides are gearing up for the state-level redistricting fights that will occur with the arrival of data from the most recent nationwide census.  Gerrymandering is the oldest geostatistical art, but it doesn't have a long history in the public eye.  This could be intentional; dividing a republic into fair, representative districts is both a philosophical and a practical exercise, mind-boggling in its complexity.  Small wonder that it becomes a game of party advantage, played by a select few.

Two recent projects have sought to shed some light on the process of redistricting:

• The Redistricting Game, produced by Annenberg Center for Communication and the USC School of Cinematic Arts.  It raises all sorts of insights about how the current process is tailor-made to reinforce partisanship, including this excellent point by David Winston, a former RNC mapping strategist: 

" . . . When I, as a mapmaker, have more of an impact than the voters, the system is out of whack."

From The Redistricting Game (USC, 2010)

• David Sparks could be referred to as a "Cartographic Political Scientist". His recent work on redistricting alternatives should - and most likely will not - be considered at the national level as a fairest way to subdivide the population into voting units. In a manner not unlike the geodemographic segmentation analyses offered by GeoSprocket, he's created voting districts based on the greatest possible contiguity, or the shortest travel distance for voters to their district center. This is a stated - but largely ignored - goal of redistricting today; contiguity is usually only considered when it works to party advantage.

Demo "Contiguous" Districts in North Carolina (D. Sparks, 2010)

Geospatial technologies have proven to be essential tools for partisan demographic division in politics.  In a representative democracy, how can spatial analysis be used to promote real representation?

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Memory and the Vertical Perspective

Yesterday Google marked the 150th anniversary of the first aerial photo acquired in the U.S.  They overlayed the photo (of what is now downtown Boston) on Google Earth imagery, and set it at the appropriate viewing angle in the video above.

In the scope of human history, aerial photography can seem like a very young technology.  But for those of us watching the updates and advances roll out on a near-daily basis today, the 1860 image of Boston has a ghostly quality, as though we're looking into the past through a window that shouldn't exist.  I often get a similar sensation when analyzing land surface changes over much shorter timescales - looking at forest mortality since 1980, for instance, or urban growth between 1970 and 1990.  It seems like pixels should have a harder edge to them than memories, but they often feel like ephemeral impressions.  This is especially true if they represent something lost like the Boston Common of 1860, or the Cornfields of South Burlington, VT in 1937:

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