Yellow flowers growing along the median of Connecticut Avenue looking north toward Dupont Circle, Washington, D.C., 7:03PM April 30, 2013.
My (personal) update is actually at the bottom of this entry. In the meantime, I'd like to post the findings and main images from this fascinating article I found on Tuesday. The images below are from the article. The first four are each a "gyradius" for the given city (discussed in the text).
Gyradius for the San Francisco Bay area for subset of 2011 Tweets used in study.
On Tuesday morning, I came across on Yahoo news the article "Pretty City Images Reveal How People Move". Originally published on LiveScience.com here, the article discusses a scientific study on the movement patterns of people as tracked by "geotagging" (geo-locating) fully 37 million Tweets of 180,000 people in 2011.
Gyradius for the Chicagoland area for subset of 2011 Tweets used in study.
Intrigued, I went to the article that is available on the pre-print website arXiv here and it contained a lot more than the article covered.
The 23-page article entitled Happiness and the Patterns of Life: A Study of Geolocated Tweets is by Morgan R. Frank, Lewis Mitchell, Peter S. Dodds, and Christopher M. Danforth, all mathematicians at the University of Vermont, Burlington.
Gyradius for New York City area for subset of 2011 Tweets used in study. (I think this image focuses just on Manhattan and parts of Brooklyn.)
The researchers were able to map patterns of people movement through a "gyration of radius" or "gyradius," which refers to the linear size occupied by an individual's trajectory during the course of a day and is thus a measure of human mobility.
Gyradius for the Los Angeles basin for subset of 2011 Tweets used in study.
They created gyradius plots for four U.S. metropolitan areas including New York, Los Angeles, Chicago, and San Francisco. The redder colors indicate Tweets from people in the suburbs who travel shorter distances from home while the yellower colors are Tweets from people in the urban cores.
The Los Angeles basin gyradius shows that people travel shorter distances, which interestingly, seems to correlate with a recent point by Paul Krugman made here about changes in "population-weighted density" figures for U.S. metropolitan areas. In particular, he had a discussion about the L.A. area, and how it is hemmed in by the mountains, and how that geophysical fact has altered and sets an upper limit on its sprawl. This is keeping with his view of how metropolitan areas are developing into series of small urban clusters around established central ones.
See paragraph below for description of this image.
They also created (quoting from the article): "a probability density function of observing an individual in their normalized reference frame, where the origin corresponds to each individual's expected location, and σy = 0 corresponds to their principle axis. This map shows the positions of over 37,000 individuals, each with more than 50 locations, in their intrinsic reference frame."
That is, I think the above plot is for a subset of the 180,000 individuals who were located in more than 50 locations.
The researchers also employed something called a text-based "hedonometer" to characterize sentiment (feelings) as a function of movement (and distance), and they created word shift graphs to measure how happiness shifted with distance from home, although I didn't fully understand those graphs with just a cursory reading. Obviously, it's not possible to know the intended meaning in all cases, but presumably the words chosen are assumed to reflect happiness or unhappiness.
Click on image for larger version -- and check out some of the words, although you may have to look at the article itself to read them more clearly. (For an explanation of these graphs, see Figure 7 caption in the article.)
A key finding (which maybe isn't all that shocking) is that "expressed happiness increases logarithmically with distance from an individual's average location."
I suppose this refers to Americans on vacation of some sort, as opposed to refuges in Africa.
View along the 1700 block of Rhode Island Avenue NW, Washington, D.C., 7:05PM April 30, 2013. That's the YMCA where I go that I was approaching.
I brought the computer home tonight, and so I can post a new entry. And there are so many things I would like to discuss. However, I'm so tired and any topic I start will invariably spiral out of content and image control.
Post-midnight entry on this the first day of May. It's May Day, and it seems to involve a maypole, especially judging by the various blog hits I've been having on the term "maypole" -- specifically, this image.
My work day was OK, and thereafter, I had a workout comparable to last night at the gym but with a 5.00 mile jog. I also spent an hour weight-lifting (OK, not continuously and using the machines, not free weights) and then 20 minutes rather than the usual 30 minutes swimming. I was a bit tired and the pool was a bit busy.
In addition, I really wanted to get a decent meal at the Thai restaurant Bua before it closed (at 10:30PM) rather than eating haphazardly this-and-that at home (which doesn't, er, digest very well).
I am taking tomorrow evening off from the gym (and probably go to No. 9 for happy hour). I'll go again on Thursday.
Oh, yes, that incredibly attractive guy -- beautiful face, even more beautiful body -- was again in the pool tonight. I talked to him once just to make a quick comment (I think I mentioned this) and waved to him last night. And that black spiked hair he has, except it's all slicked back when he is wet. I simply cannot tell if he's a really hot Latin guy or Middle Eastern / Arab or maybe even Iranian.
Right now, I'm watching reruns of The Golden Girls on Hallmark Channel right now.
The weather tonight is cool and partly cloudy with a lingering easterly / maritime flow. There was some drizzly showers earlier today but rainfall amounts the past two days have been very minimal and we remain below normal, and precip. is now over for the next several days (though at least it will be cool).
Here are the updated numbers through midnight (so for the full month of April) at the three regional airport climate stations.
April: 2.79" -0.27" (3.06")
Year: 9.79" -2.18" (11.97")
April: 2.20" -0.99" (3.19")
Year: 10.43" -2.61" (13.04")
April: 2.30" -1.17" (3.47")
Year: 10.79" -1.48" (12.27")
I'm unsure if this still more a climatological deficit than a hydrological one.
OK, that's all for now. My next update will either be on Thursday or Friday night.