That I picked up on this contrast is perhaps a bit ironic, as Mr. Brune as an activist was known for a rather confrontational style, as elucidated in a Living on Earth interview, a KQED Forum interview, and in a Grist article. Prior to the Sierra Club, Mr. Brune was executive director of Rainforest Action Network, where his most notorious stunt involved the campaign to get Home Depot to stop buying wood from endangered forests. Sympathetic Home Depot employees contacted Mr. Brune and clued him in to the code for the Home Depot intercom system, by which Rainforest Action Network activists could go into any Home Depot, find the intercom stations, and broadcast messages storewide about the source of the wood products for sale. This campaign worked, although I’m not really sure this is the sort of thing I’d like the Sierra Club to start doing more of.

Mr. Brune made what I think is a salient and subtle point in praising the Sierra Club for “evolving” over the past decade or so, of doing a good job of “holding onto its roots”–protecting wild places and the like–but at the same time “being responsive to the great threat of climate change.” This phrasing speaks to me–it signals an understanding that the environmental challenges we face and our responses to them are not identical to those of twenty or thirty years ago. Urban environmentalists often note a disconnect with what we might call “traditional” environmentalism, manifested as an insistence in saving every tree, and in opposing every development, and in always primarily characterizing the principals involved in any development as greedy, even if the trees that would have to be cleared to make way for a development would enable its future residents to live in ways–without cars, for example–that could drastically reduce their overall environmental impact when compared with what they might need to end up with should the traditional environmentalist’s protests be successful and should the greedy developers choose to build their buildings instead on some further-flung plot of land that’s less dear to said environmentalists. I’m oversimplifying the issue here of course, and I don’t want to presume that when Mr. Brune says the Club is evolving that he necessarily means that it will evolve exactly the way I want it to.  But it does seem to me that Mr. Brune is acknowledging the need to look at environmental challenges in a different way than has been considered traditional.

Two years ago, he wrote Coming Clean–Breaking America’s Addiction to Coal and Oil, published by Sierra Club books. That energy was the topic on the mind of someone employed to save the rain forests is, itself, encouraging. He was interviewed on Sierra Club radio for September 6, 2008 upon release of the book, and this earlier interview is perhaps more insightful than the current one. He struck a thoughtful and diplomatic tone, giving respectfully detailed answers to complex topics. He discussed, at some length, the problems with biofuels, beginning with a remark that the idea of growing your own fuels is, no doubt, very alluring. He concludes that “biofuels can only at best be part of the solution” and further noting that if we were to turn every single last ear of corn produced in the United States into ethanol, it would provide a scant 12% of our fuel needs. He resists the temptation to simply classify biofuels as “good” or “bad,” and he uses a quantitative figure in a proper and meaningful way, which is more than can be said of much of what passes for environmental discourse these days. The urbanist will also note that he also understands that biofuels are an attempt at a solution to what is in many respects the wrong question–instead of asking how we’re going to keep fueling our cars in a post-carbon age, we should also be asking whether we need so many cars to begin with. Brune mentions, several times, that ”we need to promote ways of transportation that are not centered on the automobile.” When asked for ways in which individuals could get involved in breaking our oil addiction, he suggested getting involved with your local bicycle advocacy organization, to get more bike lanes and to encourage office buildings to offer bicycle parking.

It also appears–although not having read his book, I’m not certain–that he wants to play down the role of individuals greening their own lives and instead look towards action for large-scale, widespread institutional change. In the 2008 interview, the host specifically asks him about a claim in the book that individual actions, like turning down your thermostat and changing out your lightbulbs, won’t be sufficient to solve the climate change problem. And although he’s not as polemic as Mike Tidwell’s Washington Post Op-Ed, the sentiment is the same: to make the changes that matter, we need large scale, collective action. And Brune makes clear in the current interview that be believes that there is no organization better suited to lead this action than the Sierra Club.

Brune, I couldn’t help but notice, is only two years older than I am, and is probably as young as one can be to also have enough experience to be considered a reasonable candidate for executive director of an organization with the size and stature of the Sierra Club. Carl Pope, I gather, is a few years younger than my parents. So there really is a transition here, a passing of the baton from one generation to the next. I’m optimistic about Brune, and will watch carefully to see where the Club goes.

With such a mass of talks going on, planning your time at the conference and deciding how long to stay take some effort. In the past, abstracts for all talks, and the 2000 or so posters that the meeting has each year and were printed in two volumes that resembled phone books, plus a pocket sized book of session titles. These days, one gets a smaller books that lists only the titles of the talks, and of course the entire program is also available online. Nevertheless, over the years I’ve found the layout of the program to be a bit wanting, and so I put together some scripts that parse the schedule and author information to print it out in a form that I find easier to work with.

My scripts and their outputs have evolved over several years, and currently they produce three files. They take as input the Epitome, which is a chronological list of sessions, and the list of invited speakers. At present, both of these must be cut-and-pasted from the meeting website into text files for my program to read. (Maybe next year I’ll have them automatically grab the files from the APS website.)

The first output file is a version of the Epitome more suitable for browsing on a printed page than the materials for APS. It skips the non-talk sessions (like receptions and unit business meetings) and makes sure all sessions of each time block are together on a single page.

The second file serves to give a sense of the structure of the March Meeting: it is a grid of time blocks versus session numbers, with symbols indicating the number of invited talks in each session. It also has a list of room numbers associated with each session number: for the most part, all sessions of a certain number (such as A14, B14, D14, and so on) will be in the same room, but not always.

The third file is a list of invited talks, sorted by session instead of by author last name. Because of the large number of parallel sessions and the high likelihood of schedule conflicts, I think it makes sense to look time block by time block.

Since this year I’ve actually got these files produced well before the meeting, I’m posting them here in case anyone else should like to use them too.

Here are the three PDF files I’ve generated:

Epitome_Mar10

Grid_Mar10

Invited_Mar10

If you like the information but want to fiddle with the formatting, here are the .tex files that generated the PDFs, that need to be run through LaTeX. Because of a quirk in Wordpress, they’re all saved as .tex.txt. The APS online information already uses TeX formatting for accent marks in speaker names, and for super- and sub-scripts in talk titles. (There are occasionally errors in APS’s TeX formatting–this year, the title of Philip Anderson’s talk is missing the math mode $ characters surrounding the ^3 superscript command. Despite my efforts to automate everything with these scripts, fixes like this still must be done by hand.)

Epitome_Mar10.tex

Grid_Mar10.tex

Invited_Mar10.tex

Finally, here is the Tcl script that I use to parse the files and write the .tex files. It’s not very good code, having been mucked around with once a year for a few years and in general cobbled together from earlier scripts. It works, provided the settings file is appropriately edited, on march meeting files back to 2006, when the invited speaker list was first published online. The bits that work on the epitome work on 2005, and the epitome format in 2004 and earlier years was different. As with the .tex files, I’ve needed to upload them as tcl.txt files here.

march2tex.tcl

march10_settings.tcl

In a future post, I hope to use the results of the scripts, particularly the grid, to analyze ways in which the March Meeting has changed over the years.

Matthew, though, has logged more mileage in the air than by any other means: to date, 29063 miles in 26 segments. Most of this has gone well. We’ve always bought him a seat, even when he was young enough to travel as a “lap child.” In the past, it was common to travel with a young child as a “lap child” and then use an empty seat for him while aboard the airplane, but in recent years, there is no such thing as an empty seat, and lap children must almost always actually be carried on a grown-up’s lap for the whole flight. My advice, then, is not to count on there being an empty seat, but rather, to count on there not being an empty seat, and if you can at all afford it, buy the seat for the child.

Of course, even when you buy a seat for your toddler, and you tell the airline such when you buy your ticket, you may find, when it’s time to select seats, that there are none together. Your toddler might even be assigned a middle seat by himself ten rows back from mommy and daddy. Don’t panic! As crazy as some airline practices might be, they would never actually seat a toddler away from at least one parent. Further, in all the 26 segments we’ve flown with Matthew, the three of us have been separated only once (and on that flight, he slept the whole way through).

This is not because we’ve always bought our tickets early enough to select a whole row of seats together–we often get nothing good left to select from, and we’ve also had flights cancelled and have needed to squeeze on later flights. But if you can’t select good seats when purchasing a ticket, have patience and wait until you’re at the gate. If you are assigned seats apart, nobody will be able to help you get seated together except the gate agents: not customer service on the phone, not the front counter agents where you check in, and, unfortunately, not any agents at an airport that’s not the one where the flight in question departs from, which makes tight connections rather nerve-wracking. I once spent the better part of an hour on the phone with an airline’s customer service department, speaking to the phone agent’s supervisor, only to end up with a worse seating assignment than the computer had automatically given us. The gate agents fixed the problem, as they have in every single other time we’ve had seats assigned apart, with the worst outcome being that one time Matthew and his mommy were together while I was several rows back. So the best thing to do is to be at the gate as soon as the flight is posted, which is usually no more than an hour before departure.

So one way or another, we’ve almost always had a row of three seats to ourselves. The fact that we buy a seat for Matthew does not imply that he stays in the seat for the entire journey–he only does this when he falls asleep. But even if he doesn’t use his seat, having the whole row to ourselves makes quite a difference, as he can be moderately active without disturbing anyone else.

Every time we’ve needed to travel in a car on the other end of our trip, we’ve brought on board and installed his carseat in the aircraft, then subsequently installed it in the car at our destination. Car seats could be obstructions to other passengers, so on single-aisle aircraft, they have to be installed in the window seat, which the gate agents have always given us. Our infant car seat installed almost trivially on airplanes–the seat belt cinched across two hooks just above the baby’s legs. Matthew currently uses a Sunshine Kids Radian 80 carseat, which works quite well for air travel. The seat quickly folds up into the back for storage, making it relatively compact to haul around. With an extra strap, it can be worn as a backpack. The belt path, for the forward-facing configuration, is readily accessible underneath the seat back padding. It fits through X-Ray machines, and we’ve had no troubles from TSA about it.

We’ve frequently taken our stroller along as well, and it fits through the X-Ray machine and also hasn’t given us any trouble at security. Incidentally, the TSA does require that infants’ and toddlers’ shoes be removed for security screening, just like with grown-ups. We had quite the routine down, getting the three of us and our shoes and the carseat and the stroller and a diaper bag and our carry-ons–with laptop computers out, of course–through security. We are grateful for the “family line” when TSA provides one.

We’d check the stroller at the gate, dropping it off and picking it up at the end of the jetway. Although it’s quite handy for movement about the airport, we’ve also found that we don’t always use the stroller much at our destination–sometimes it’s stayed folded up in a rental car the entire time. So we’ve experimented recently with stroller-free traveling: we didn’t bring it along on our last airplane trip, nor on our train trip to Chicago, and both of these worked out rather well.

For the one airplane trip in which we did not need to subsequently travel in a car, we used the CARES harness. This allowed us to put Matthew in the middle seat instead of the window. One strap for the CARES harness does need to be installed underneath the tray table for the seat in the next row back.¹ In part because Matthew wasn’t used to this harness, it did seem like it was harder to get him to cooperate with getting strapped back in when we needed him to be, compared to his carseat. On our recent Amtrak journey we left the carseat at home–there is no need or way to install a carseat (or harness) on a train–and we rented a carseat with our rental car. That worked out fine, so perhaps we’ll use the CARES harness more as we seek to haul around less stuff as we travel.

1. In a small number of situations, where the tray tables stow flush with the seat back into a cavity, and the strap around the tray table would not follow the contour of the cavity, that the tray table–of the person in back of the child–would not be able to be opened if the harness were in place.

But it turns out you can grow things using the lackadaisical approach, and in our case, it’s pumpkins.

This is how the pumpkin plant looked in September.

The truly amazing bit is that I didn’t ever plant any pumpkin seeds. The pumpkin vine grew out of a side vent in our compost bin, presumably from a pumpkin seed that germinated instead of decomposing while inside the bin.

Since I didn’t plant these, I don’t actually know which variety of pumpkin they are, but I presume they are the inedible jack-o-lantern type from Halloween 2008. As with everything else in the yard, I didn’t tend to these, so they didn’t grow nearly as large as a proper jack-0-lantern would. Indeed, the pumpkins feel solid, not hollow.

I “harvested” them recently, although too late to be a part of our Halloween decorations. But, for the record, here is our garden output 2009:

• hard-wired, with
• battery backup, and
• interconnected

The batteries in battery-powered smoke alarms will run out. They do chirp to let us know it’s time to change the battery, but more often than not I won’t have a spare battery handy, or I won’t have a step stool nearby, or it will be the middle of the night, so instead of going back on the ceiling with a new battery like it’s supposed to, the alarm will sit around on a counter, battery-less, sometimes for weeks. Hard-wired smoke alarms solve the dead battery problem because they draw their power from the house electrical wiring. As it turns out, electrical fires that disrupt the power before smoke could be detected are really rare, and our power is pretty reliable, so the risk that the power’s off when the alarm needs to sound is really quite small, smaller than the risk that your battery-powered alarm will be sitting, battery-less, on the counter. And most hard-wired alarms also have battery backup, so you’re covered during power outages, too.

There are two smoke-detection technologies: ionization and photo-electric. Ionization sensors do well with small smoke particles, from fast-burning fires, while photoelectric sensors do better with large smoke particles from smoldering fires. Most safety recommendations (including Consumer Reports) are reluctant to specify one as being a better choice, and recommend both. So add to our wish-list:

• dual-sensor

Interconnection of smoke alarms means that when one alarm goes off, all of them sound. So if there’s a fire in the basement while you’re asleep, the alarm in your second-floor bedroom will also go off, giving you much more time to escape than waiting either for enough smoke to set off a second-floor alarm or for you to hear the far-away alarm. The interconnection is conventionally done with three-conductor wiring: all the smoke alarms need to be installed on the same circuit and the third wire is used as the alarm interconnection signal wire. This is easy in new construction but really hard to retrofit: getting a new circuit to the ceiling of every location for a smoke alarm would mean lots and lots of holes in the walls and ceilings.

So an easier method for retrofit has emerged: wireless interconnection. The smoke alarms can still be hard-wired, but can be on different circuits, typically extended from existing ceiling fixtures. Sounds great! Kidde and First Alert both manufacture such systems. But each offers only one sensor type! Kidde’s hardwired with wireless interconnect detector uses an ionization sensor; First Alert’s uses photoelectric.

So which to choose? Compulsive complete-ist that I am, I scoured the internet looking for advice comparing the two detection methods, and eventually came across the NIST report which I believe all other advice is based upon. Like everything else I found, it, too, doesn’t recommend one technology over the other, but by sifting through its data, I’ve concluded that I definitely want both sensor types in each room, even if that means installing two smoke alarms in each room.

The NIST tests set fires of several types (flaming, smoldering, cooking) in two settings: a trailer home and a two-story home (although one without soffits between the rooms and the hallways). They measured the time it took for alarms of different types to sound, and also the time between the alarm sounding and the moment at which escape becomes “untenable,” meaning that the smoke density had reached some critical level.

For flaming fires, what struck me was that the total time between the start of the fire and the onset of untenable escape conditions was between 150 and 400 seconds. Ionization detectors sounded 24 to 64 seconds earlier than photoelectric, which is a significant amount of time on the time scale of flaming fires. Other research cited by NIST indicates that it can take the average person 50 seconds to actually exit a house, taking time to put on a bathrobe, grab wallet and keys, wake children up, and so forth. 

What isn’t said, but can be inferred, is that interconnected ionization detectors give the best and likely only chance to rescue, say, a child, from a bedroom in which the fire starts. The times to untenability only refer to the escape of people who aren’t in the same room as the fire. Fire codes “are not designed to protect people intimate with the initial fire;” survival in the same room as the fire is an entirely separate, more complicated, and controversial topic. But needless to say, every second would count in such a situation, thus the extra speed of an ionization detector in the afflicted room, plus interconnection to immediately let everyone else in the whole house know, would give as many extra seconds as possible.

So we know we want ionization detectors. What about photoelectric? Well, the total times to untenability for smoldering fires fell between an hour and an hour and twenty minutes. In many cases, photoelectric detectors responded 15 minutes to an hour faster, time scales which are significant fractions of the fire time. Catching such a fire 15 minutes sooner could significantly reduce the damage done by a fire–it might even give enough time for a homeowner to take care of the fire with a fire extinguisher. The only instances when photoelectric detectors didn’t outperform ionization detectors for smoldering fires was when the detector and fire were far apart: a fire in a bedroom with its door closed, with the smoke alarm in the nearby hallway, or a living room fire with the alarm in the hallway. But if there was an alarm in the room in which a smoldering fire started, the photoelectric detector sounded significantly sooner.

So, for now, two alarms per room.

Of all the yuppie housewares catalogs, NapaStyle is one of the yuppiest, to the point of almost being a laughable self-parody. But I’m writing here about something I bought from them (a NapaStyle exlcusive, even) that’s turned out to be quite a satisfying purchase: the Stemware & Plastic Baggie Dryer. I hate to throw away plastic Zip-Lock bags after just one use; far better to wash and re-use them. This device is a ring of eight wood rods that make excellent places to hang plastic baggies to dry.

Of course, one doesn’t need a drying rack to wash and re-use plastic baggies, but I wasn’t regularly doing so until I bought this drying rack. The drying rack works very well for its task. It’s also a very unassuming product: it does not need to have its own box: it was simply placed inside the shipping box. It was not enclosed in a plastic bag, it was not packed with custom-fit styrofoam. It was not tied to a piece of cardboard with twist-ties. It required no assembly. It came with no manual, no marketing survey disguised as a warranty card, and no safety warnings. It has no website. You can’t get on it’s email list for exciting product updates. It’s made almost entirely of wood. It was made in Canada. 

I wish more products were like that.

Now the blossoms have blown away, and trees of every type are getting their leaves, and for a week or so the trees are all decorated in Spring Green. I had known about the Crayola color Spring Green since childhood, but it wasn’t until I was living in Ithaca that, after a characteristically long winter, I really understood what it meant. The very light and yellowish green of the nascent leaves on the trees across the street from my apartment were Spring Green; it was finally spring.

So now we begin the six or seven months in which the foliage and blooms of the plants around us make the city beautiful. This is capped by a month or so of fall foliage, after which nature’s beautification fades, slowly, and the seasonal decoration takes over. 

Between Thanksgiving and New Year’s, holiday lights make the otherwise bleak city beautiful. Strings of white lights outlining houses and filling in shrubs, some overdone, some very subtle: they compensate for the dwindling sunlight and dormant vegetation. In Ithaca, we got our first snow around Thanksgiving, here in DC it comes much later, usually in January. Snowfall is only very briefly beautiful, when it’s still piled up on otherwise bare branches, and while that on the ground hasn’t been disturbed very much. Then in a few hours, it drops from branches and twigs, and snowplows and other traffic have turned much of it into a dirty grey mush.

One thing I can’t understand is why it is that the holiday lights that made the streets seem so inviting in December look so tacky in the middle of January. The weather is the same, the hours of darkness are much the same, yet holiday lights, and the greens, golds, and reds of Christmas look fantastically out of place. I suppose we’ve been trained by the retail industry to appreciate bold reds and whites, à la Valentine’s day. Is there anyone who actually buys such seasonally-colored servingware from the yuppie housewares catalogs? And after Valentine’s day, as the dreary bleakness of winter presses on, we imagine spring in pastel colors. And then spring happens, like it’s happening now, here in DC.

Sessions
For a number of years now I’ve taken the online Epitome and Invited Speaker List and run them through tcl scripts to make TeX files that give me speaker and session information in a format I think is more useful. This also allows me to look at overall meeting statistics: There were more sessions this year, 558, than in previous years; last year there were 517 sessions. What seems to be growing most sharply are invited talks: there were 825 this year, compared to about 730 in each of the previous three years. Not surprisingly, this corresponded to an increase in the number of sessions with 5 invited talks: there were 95 such sessions this year, about 75 in each of the previous 3 years, and only 15 back in 2005.

Reunion
I only stayed through Wednesday of the meeting this year, taking an evening flight back home. I was rather irritated to find that the Cornell alumni reunion was held on Wednesday night, instead of Tuesday, like it always had been. I don’t know if this had even been published before I made my travel reservations, although I don’t know that I would have stayed an extra night just for that.

Projection
The disappearance of viewgraphs now appears complete. I was one of a handful of holdouts who was still using viewgraphs as late as 2006. Last year, I only saw one talk given using viewgraphs and this year I saw zero. There are still overhead projectors in the rooms, but they are kept on the floor beside the table upon which the computer projector sits. It’s amusing to read the note in the 2002 newsletter of the Division of Condensed Matter Physics:

More and more scientists want computer projection for their talks. This past year, computer projectors were available in invited session rooms only. Projectors are very expensive (~$400/ day/session) and would raise the registration fee at the conference significantly if placed in all rooms. Also, set-up time between talks makes staying on a 12 minute schedule for contributed talks very problematic. APS will continue to increase the availability of computer projection, but will not commit totally to them until price and technical interfacing problems become more tractable.

To be sure, there are problematic computers and I did see talks where roughly half of the time was taken up with computer fiddling. 

Context
On the topic of presentations, one thing that lots of speakers do, which really bugs me, is to show a graph of some raw data, usually a spectrum of something taken with a well-established experimental technique, but without giving any explanation. If I don’t use a technique myself, even if I know in principle how it works, I don’t know if it’s considered good or unexpected or interesting or disappointing if your graph has wiggles, or is flat, or has a bump in a particular place, or a big spike, or a big dip, or if it shifts a little as you twiddle some parameter, or shifts a lot. Context, my fellow physicists! Tell us what your measurement technique does, what shows up in your graph, what ordinary data would look like, and why your particular measurement is interesting.

Books
I also ended my one-year physics-book-buying drought. I buy interesting physics books knowing that I’m not also buying the time it takes to work through them. I have one book purchase from two years ago that I’ve made a concerted effort to actually work through, but am perhaps only 20% done with it. And it’s not even a very challenging book. But I went ahead this year anyway, and took advantage of Cambridge University Press’s Wednesday afternoon buy-2-get-50%-off sale to pick up an otherwise ridiculously overpriced Elasticity with Mathematica and Geometric Algebra for Physicists, and also bought Group Theory: Applications to the Physics of Condensed Matter.

On to Portland
I’m looking forward to visiting Portland for next year’s March Meeting. I consider Portland one of my favorite cities but in reality all I’ve only spend several hours there at a time, waiting to change trains. But with a streetcar and Powell’s, who couldn’t love Portland? I had been sure that, a couple of years ago, I also saw Seattle on the list of upcoming March Meeting locations, but it seems to be gone now.

How many are there? I calculate:

The 28 intersections that appear in all 4 quadrants are:

14th & D, 9th & G, 7th & I, 7th & E, 7th & G, 7th & D, 6th & C, 6th & G, 6th & D, 6th & I, 6th & E, 4th & M, 4th & G, 4th & E, 4th & D, 4th & I, 3rd & M, 3rd & C, 3rd & K, 3rd & D, 3rd & G, 3rd & E, 3rd & I, 2nd & E, 2nd & C, 1st & M, 1st & C, 1st & N

Plotted on a map:

Color coded map of intersections in DC.

Update: Here’s a larger PDF version.

Here’s how I made the map and did the calculations:

I started with the same Street Centerline file that I used in my first post on GIS with Mathematica. The elements of this file are lines representing street segments between intersections, so the first and the last point defining each line lie at intersections. First, I take from the rather unwieldy raw data and make a new list where each element corresponds to one street segment, and within each of these elements, the geometry is followed by all the other data:

dcstreets=Import["StreetSegmentsLn.shp","Data"][[1]];
dcstreetdata =
Transpose[Join[{dcstreets[[2, 2]]}, dcstreets[[4, 2, All, 2]]]];

Then I wrote two functions to pick off the data I need: for each of the first and last points, representing the locations of the intersections, I need the street name, type (e.g. Street or Avenue), and quadrant:

nodeFunction = Join[{#[[1, 1, 1]]}, #[[6 ;; 8]]] &
tailFunction = Join[{#[[1, 1, -1]]}, #[[6 ;; 8]]] &
nodelist =
Union[Join[Map[nodeFunction, dcstreetdata],
Map[tailFunction, dcstreetdata]]];

Map applies the specified function to each item in the list of street segments, and the resulting lists of beginning and ending intersections from all the segments are put together with Join. Of course, most streets run through numerous intersections, and the second intersection of one segment will be the first intersection of the next segment. To make sure we get the beginning and ending of each street, we do need both the first and second intersection from each, and we use Union to remove all the duplicates from the middle.

We now have a list in which each element contains a location and street name. We now need a list of all the intersections–when two streets share the same point. Fortunately, Mathematica 7 introduced the GatherBy function, which groups a list depending on the value each element returns from the specified function. In this case, the specified function is just the first element, that is, the location:

intersections = GatherBy[nodelist, #[[1]] &];
In[]:= BinCounts[Length /@ intersections, {1, 6, 1}]
Out[]:= {901, 7015, 491, 20, 2}

The second line tells us that there are 901 end-points with only one street (the majority, I believe, are where the streets lead outside the District boundary), 7015 points where two streets come together; 491 points where three, 20 points where four, and 2 points where 5 streets come together. Which are these? With

Select[intersections, Length[#] == 5 &]

We find that the first is the intersection of 15th Street, Benning Road, Bladensburg Road, H Street, and Maryland Avenue NE, while the second is the intersection of 51st Street, Doewood Lane, Eastern Avenue, Mann Street, and Meade Street NE.¹ For our purposes, we want to consider all these as pairs, so we break all intersections with three or more streets into their respective pairs:

intersectionPairs =
Flatten[Join[Subsets[#, {2}] & /@ intersections], 1];

Since I’m using the Street Centerline File, the streets that serve as quadrant boundaries–North Capitol, East Capitol, and South Capitol streets–are not given a quadrant but given the designation “BN” for boundary. Actual addresses on these streets are given a quadrant depending on which side of the street they’re on. In this scheme, you’ll get intersections such as 17th Street NE and 17th Street SE, where they intersect East Capitol Street. I’m ignoring those for this exercise, and then using GatherBy again to find all the points where the intersection street names are the same:

quadrantPairs = Select[intersectionPairs, #[[1, 4]] == #[[2, 4]] &];
multipoint =
GatherBy[quadrantPairs, {#[[1, 2 ;; 3]], #[[2, 2 ;; 3]]} &];

Looking at the structure of this we see a little more work to be done:

In[]:= BinCounts[Length /@ multipoint, {1, 7, 1}]
Out[]:= {6287, 741, 101, 36, 7, 1}

Which tells us that there are 6287 unique intersections in DC, appearing in only one quadrant; 741 that appear in two quadrants, and 1 that appears in 6 quadrants???

This happened because Stanton Square is considered to be a giant median for C Street NE, so there are actually three distinct points that could be considered the corner of 6th and C Streets NE, all along one block. There are also intersections of 6th and C streets in NW, SE, and SW, giving a total of 6. For this, though, I want to treat all the locations in NE as the same, so I make my lists of quadruply, triply, and doubly-redundant intersections depending on how many quadrants appear, which I count with Length and Union:

quads = Select[multipoint,
Length[Union[Flatten[#[[All, All, 4]]]]] == 4 &];
triples =
Select[multipoint, Length[Union[Flatten[#[[All, All, 4]]]]] == 3 &];
doubles =
Select[multipoint, Length[Union[Flatten[#[[All, All, 4]]]]] == 2 &];

Giving lists of intersections, the lengths of which were quoted above. Relatively simple graphics commands made the figure, to which I added the DC Boundary polygon from another .shp file.

Figuring this out took far more lines of code than the modestly few lines that I can reproduce this exercise with. The keys were learning to use the new GatherBy function and getting used to the idea of Union as a list management tool, as opposed to simply part of the set theory functionality. And as usual, knowing how to use Map and pure functions are necessary for doing almost anything elegantly in Mathematica.

1. Doewood and Mann are actually the names of 51st and Meade Streets when they cross Eastern Avenue into Maryland, however I believe DC responsibility actually extends 50 feet or so beyond Eastern Avenue, hence the inclusion in the GIS data.

A friend, in town and staying with us for the inauguration, and I left the house at 7 in the morning, somehow thinking that would be early enough. The station platform at the Brookland Metro was crowded when we arrived, and the inbound train that arrived was so full that only a handful more could board. We instead rode outbound one stop, thinking that either we’d catch a slightly less full train, or could get on one of the special presidential bus routes. Miraculously, there was just enough space for us on the next inbound train, which otherwise looked as crowded as the first.

We managed to meet a bunch of my friend’s friends downtown, at their hotel, at 8. We were north of the mall. Since all of the parade route along Pennsylvania Avenue from the Capitol to the White House was walled off, we had to choose a route south.  Among the many roads closed to motor traffic that day was 395, the freeway in a tunnel that goes under the Capitol reflecting pool. It was open as a pedestrian route, and in part because of the novelty of walking it, that’s were we went. Later, we heard that the handful of crossovers through the parade route became impossibly backed up. We entered at about 3rd and G NW and exited at E Street SW. We made our way along E, then up 7th to D, then along D to 14th, where we crossed into the Mall, finding spots at the base of the Washington monument by about 9am.

And then we waited, in the cold. A half hour of relative stillness was enough to take away the warmth that physical movement generates, and I was reminded how much colder it is when you’re not moving. I knew this, but hadn’t really thought about how long we’d be out there. As was widely recommended, I had layered, and soon wished I had layered more. Perhaps what one should do is to subtract ten degrees Fahrenheit from the actual temperature for every hour you’ll be standing in the cold.

We had a decent view of a Jumbotron, and we could see the Capitol, but even with binoculars I couldn’t see any individuals. (Our view was partially blocked by trees.) What was significant was to be a part of the 1.8 million assembled, and of the 1.12 million Metro rides that day. It occured to me, standing there, that one had to understand what was going on in order to get anything out of the experience. I was glad that my son was safely and warmly at home; to be able to tell him in later years that he was there would have been a useless gimmick.

So what did I understand the experience to be? On the one hand, under the former administration, I (in chronological order): earned my Ph.D., got a permanent research job, got married, bought a house, had a child. Am I better off than I was eight years ago? Unquestionably, yes. Not bad for living a few miles from the epicenter of what was quite possibly the worst administration in United States history. But of course I was out there in the cold, celebrating with everyone else.

The president has called upon Americans to rise up to our nation’s challenges. He is not the first to call for service to our country and to others, but unlike the mawkishly sanctimonious appeals of virtually every other public leader, his carry a sincerity and gravitas that is convincing. This is perhaps because of his extensive service as a community organizer. As hope and competence replace fear and cronyism as dominant motifs in the administration, I expect that the appeal of satire and detached irony will fade in popular culture: these are for those who are comfortable, detached, and powerless. Anger and self-absorbed drama are out; hard work and careful planning are in. Does this signal an ascendancy for The University of Chicago? The President taught there, of course. David Axelrod, chief campaign stategist, went there, as did Nate Silver, whose reality-based analysis beat all the other pundits this time around. 

Four years ago, the progressive blogosphere wanted everyone to read Don’t Think of an Elephant, and now we have a progressive President that has intuitively understood framing and the use of language longer and better than anyone else on our side. Democrats should now be done with Triangulation. And Mark Penn and Terry McAuliffe, too.

On energy and environment and global warming and scores of other policies, Obama can already be said to be turning things around. Although Obama is not the first to mention science in his inaugural address, his reversal of the previous administration’s anti-scientific outlook is heartening. Perhaps our nation can be done with the celebration of anti-intellectualism. Perhaps patriotism will no longer be associated with flag-waving belligerence, but will be understood instead to be a celebration of those extraordinary characteristics of our nation that made our President’s story possible.

This was my hope, as I stood in the cold on the National Mall last Tuesday.