A Map That Helped Abraham Lincoln

Disunion Blog has an interesting post by Susan Schulten on how a new map produced by the United States Coast Survey based on the 1860 census helped Lincoln and the public visualize the geography of slavery.

The map was produced with what at that time was a cartographic innovation.. the use of a shaded color ramp to represent ranges in values.. in this case the number of slaves per county in the southern states.

Source:  Geography and Map Division, Library of Congress via Disunion

From the post:

The map reaffirmed the belief of many in the Union that secession was driven not by a notion of “state rights,” but by the defense of a labor system. A table at the lower edge of the map measured each state’s slave population, and contemporaries would have immediately noticed that this corresponded closely to the order of secession. South Carolina, which led the rebellion, was one of two states which enslaved a majority of its population, a fact starkly represented on the map.

The comment thread is interesting too... especially this argument.

Remotely India # 2: Dyke Swarms Of Northern Deccan Traps

Around Nandurbar in northern Maharashtra are spectacular outcrops of a dyke swarm intruding the Deccan volcanics.

Source: IRS-Resourcesat-1

 Models of Deccan volcanism envision that most the lava came out of vents and fissures localized along two major rift zones, the roughly east-west trending Narmada Tapi Satpura rift zone along which today the Narmada and Tapi rivers flow westwards and which initially developed in the Proterozoic but has been active intermittently since and the north-south trending West Coast rift zone which developed during the mid-late Cretaceous as India broke away from Madagascar around 90 mya. There are dyke clusters along these major rift zones and they are thought to be lava feeders, remnants of the pipes through which magma from deep magma chambers was brought up to the surface.

The dykes in the image belong to the Narmada rift zone cluster. They are mostly tholeiitic basalts in composition. Variations in chemical composition shows that the Deccan lava pile was built up through several major eruptive episodes. A comparison of this dyke cluster suggests that many of these dykes were likely feeders to the older and middle eruptive phases of the lave pile, although a feeder relationship with a lava flow is rarely seen in the field.

Interactive:


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Arsenic Tolerant Bacteria Press Conference

via xkcd comics:

Reporters beware..

From Acid Mines To The Human Microbiome

Nature News has a fascinating article by Lizzie Buchen on human ecology... not the ecology outside and around us - but the ecology within - on which a variety of microbiota flourish.

That variety is now under scrutiny...as scientists try to understand the linkages between the types of microbiota living inside us and our health. Establishing those linkages to the point where they could be of clinical value is a long way off but the efforts are bringing together unusual collaborations like the one where Jillian Banfield an expert on the microbiota of acid mines..the so called extremophiles.. is teaming up with Michael Morowitz and David Relman who are working on the microbiota in the intestines of premature infants.

...the connection...?

"The scientific questions are really cross-cutting," says Banfield. One example, she says, is colonization — which organisms arrive first and how the community evolves (see 'Baby's first bacteria'). "It's ecological succession," Banfield says. "If you look at the surface of a pool of acid mine drainage and imagine the first organisms to arrive, it's the same as imagining a newborn baby with a sterile GI tract, and the first organisms there." 

Plus, Dr. Banfield has experience sequencing and analyzing DNA from the microbes of acid mines where there are only a limited number of microorganisms. The infants intestine is similarly an ecosystem which has been recently colonized by only a few microbes, which makes it that much easier to categorize them using Dr. Banfield's techniques.

The article has a lot more on the emerging field of the human microbiome..it was an eye opener for me... in sheer number of cells we are 99% microbial...

how's that for a weekend thought..!

United States Water Usage Maps Through Geocommons

Just a pointer that GeoCommons, a public domain web mapping application by Fortiusone Inc has a growing collection of geology and natural resources data.

I've been having fun last couple of days downloading some U.S. water use datasets, importing them in Manifold GIS, making them map ready and then uploading them back on Geocommons. Using the Map Maker I have then presented the results in a couple of maps.

The first shows the total ground water usage by state in millions of gallons per day (colored states) and also ground water use as percent of total water use (graduated dots). Orange blocks as urban centres with population greater than fifty thousand. You can see the east west divide in water use type. The east relies a lot more on surface water. The central and western areas along with Florida in the south east rely on ground water more than the eastern states. The importance of the Ogallala or High Plains Aquifer is clearly seen in the central states as is the importance of the Central Valley Aquifer in California.

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You can drill down and bring out other dimensions of this data. For example in the map below I've plotted one of these dimensions, the ground water usage for irrigation in millions of gallons per day in the High Plains counties. The High Plains Aquifer is outlined.

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This is not a full "cloud GIS" yet in terms of users borrowing or leasing the full range of GIS functionality from a remote computer. I had to follow a hybrid approach as did other data donors in terms of using a personal GIS to process the data to certain specifications before uploading it to this online service. Still such services are gaining importance and functionality and they give users who don't own software an inexpensive tool to actively engage with spatial data.