The other day Axis Mapper Dave was working with styled maps in the Google Maps API and made a brief styling mistake—all the small roads disappeared but their one-way arrows remained.

It was actually kind of an interesting perspective on the street system, a stripped-down view of engineered traffic patterns or perhaps a measure of the confusion facing unseasoned motorists. Sure enough that same evening saw me driving in circles because of one-way streets in a place where I’d ordinarily be on foot. And in Madison, Wisconsin, pictured above, in spite of the relatively few arrows on the map it can be surprisingly complicated to cross the isthmus if you don’t start from the right spot. Anyway, with these thoughts in mind naturally I stole Dave’s styling code and tried to blank out everything else to leave nothing but arrows from one-way streets.

Unfortunately it doesn’t seem possible to do this completely with the Google Maps style options, and my samples below involved a little editing to remove yellow streets. I couldn’t figure out a way to make the “arterial” category of streets white without also turning their arrows white. Cloudmade’s style editor, meanwhile, can do that but can’t yet remove street labels. This bare-bones map is the best I could do with Google Maps; the arterial streets are just turned off entirely, leaving a mostly white-and-arrows map at the largest scales.

Whereas I have previously tried to make a map into a musical instrument, I picture these maps as dance steps. It looks easy to do the Brooklyn, but it’d take some skill to dance the Paris. I’m not about to try it myself, but when geography-based dancing sweeps the nation, I demand royalties!

Pictured at top: dance steps in the sidewalk on Broadway in Seattle, by Flickr user DrewToYou.

City skylines are one of my favorite types of scenic view. When planning to visit a new city, or even when looking to take some photos of a familiar city, I like to do some online scouting of good spots for a skyline view. I can recall several years ago browsing Google Earth, panning around and tilting the view to see terrain and guess at good vantage points. But by now Flickr users probably have just about every vantage point covered, so a more fruitful search can be done by looking at geotagged photos.

Out of curiosity I threw together some maps to show where most of the skyline views are, as defined by photos tagged “skyline” on Flickr. They are done in a sort of heat map style where brighter red and yellow indicates a higher density of photos, but they are neither real heat maps nor real density surfaces; rather they are many overlapping, mostly transparent dots, blurred a bit and mapped to a heat-like color gradient. There are no great insights that you can’t get from searching Flickr’s own maps, but it’s not bad for purposes like mine. I even learned of a new spot to check out locally; so it totally worked!

Here are some of the most photographed cities in North America, according to these guys. I did skip a few, but they tended to lack enough “skyline” tags to make for an interesting map.

New York: The brightest lights here are observation decks (the Empire State Building and Rockefeller Center), where one can view the skyline from the sky’s perspective. New York has such an abundance of skyscrapers that it’s difficult to take in the whole skyline at once from the ground, but that’s no reason not to see the views that people are favoring along the East and Hudson Rivers.

San Francisco: This city is made for scenic urban vistas. I recognize Coit Tower and Alactraz here, and can see that Treasure Island affords a nice view, but there are also some concentrations closer to the center of the peninsula that are beyond my knowledge of the city.

Chicago: All things considered, Chicago gets my vote as the best skyline in the country. There are several predicable popular spots here, such as the Museum Campus, the Sears Tower (or whatever it’s called now), and the John Hancock Center. But most interesting is the hotspot on Millennium Park, and specifically on the Cloud Gate sculpture, a.k.a. “The Bean.” This is presumably one of the only spots among any of these cities where the majority of skyline photos are of a reflection.

Seattle: Seattle gives San Francisco a run for its money in terms of ideal scenic geography, with lots of hills and coastline. Head to Gas Works Park, the Space Needle, Queen Anne Hill, or, um, that area along the water to the southwest whose name I don’t know. Interesting to note here, as well as in San Francisco, are series of photos that follow ferry routes.

Boston: It’s a difficult skyline, with the two tallest landmark skyscrapers being in an otherwise smaller section separate from the main downtown skyline. Nevertheless there are views to be had. The Prudential tower and the Longfellow Bridge stand out the most here, the latter probably because its panoramic view is so often seen from subway trains coming up for air as they cross the river. Looks like people aren’t fully appreciating the glory of the BU Bridge, though.

Toronto: Toronto’s skyline has the privilege of being visible at great distances across Lake Ontario. Locally, though, the CN Tower is brighter than anything else on this map, but there are also some notable spots along the water’s edge in various locations. Of all the cities here Toronto is probably the least familiar to me; perhaps some readers can identify locations on this map.

Vancouver: My recollection is that Vancouver’s skyline is expansive but not terribly distinctive. But like the other west coast cities, its topography and coastline provide vantage points. The brightest points on the map are actually on land near the downtown area, but views across various water features prevail overall. I know the Stanley Park views and a couple of those to the west, but am otherwise unfamiliar.

Philadelphia: Of course the favored view is the one from the art museum, and of course all those photos are of somebody doing a Rocky impression.

Geometry riddle: When is a square not a square?
Answer: When it’s in New England.

Above (click for greater bigness) with the stupid title is a series of minimal street maps I traced to show the varied actual shapes of a selection of so-called “squares” in the central Boston area. Urban spaces come in all shapes, as you can discover with this nifty tool, and a city square in any part of the world is by no means guaranteed to be a literal square, but New England’s style of square is peculiar (at least in this country) in its especially confused geometry. Unlike many places where a square is most often defined by a public open space or civic structure, here a square is typically defined by an intersection of two or more—usually closer to 4 gazillion—thoroughfares and/or other streets. The square’s name further applies to a business district around that intersection, and sometimes to an entire neighborhood. Thus the squares strongly define much of the local geography and organization of Boston and its close surroundings, as you can see in the diagrammatic Unmapped Boston poster. They are many things, but rarely are they square. You’ll also find some Circles and Corners around town, but they tend to be a bit more true to their names.

Any locals out there can probably find fault with my selection here or with the extent of the individual square maps, but I’ve tried to capture the central intersections of many of the major players. The collection can always grow! Entertain yourself by trying to identify each square before consulting the list under the title. (Squares from Boston, Cambridge, Somerville, and Brookline are included.)

To everyone else: Sorry, I know you don’t care. But this city is just so mappable! (And in a way, undermapped.) You should come visit.

Previously: Squares can also be difficult to drive through, and they make good logos.

Edit: don’t hate me for this, but I’m in experimental stages of posting junk like this for sale at Zazzle, just in case anybody takes pride enough in their squares to put this on a t-shirt or poster. Something more professional and less desperate-looking will occur over time!

Beyond knowing the system or finding addresses, I was curious to see complete house numbering systems. I had ideas of colorful city maps representing street numbers from low to high, but my attempts failed to produce anything worthwhile because the range of numbers tends to be so great that it’s difficult to show patterns of any intricacy.

Instead, one can still get a sense of the house numbering scheme by looking at where the numbers begin. So I made a few maps to show that, based on the Census Bureau’s TIGER/Line files. Here are seven cities (the counties that contain them, actually, because that’s how the Census rolls), obviously not an extensive set nor likely representative, but showing a bit of variety. Purple blocks are those containing any numbers from 1 to 100.

Washington, DC: A perfect example of a system where numbers increase in north, south, east, and west directions from two central axes, in this case extending from the Capitol. In Washington’s case, the city is divided into quadrants. Chicago is another very orderly big city, but my computer is too weak to handle a map of all the streets in Cook County.

Atlanta: Atlanta is similarly divided into quadrants, but here streets are not as geometrically perfect, and I’m not sure if the axes always follow particular streets (or other features).

Dayton, Ohio: Had to check out my place of origin. Dayton bases its numbers not strictly on cardinal directions but (mostly) on the main north-south and east-west streets, which bend a bit. Meanwhile, the rural parts of Montgomery County appear to follow the same pattern, while individual towns do their own thing.

New Orleans: I can’t really tell what’s going on here. There is the north-south divide on Canal Street, but I can’t discern what the baseline for other streets might be. Any locals out there who can explain?

Manhattan: Another well-organized system, with numbers counting upward from 5th Avenue (and Central Park, it looks like) and from downtown. Unlike many other places with gridded, numbered streets, the addresses don’t match the cross street number, not that you can see that in this map. I vaguely recall once seeing some kind of formula for determining which block a given address is on. Any links or confirmation would be wonderful!

San Francisco: What the hell? Wikipedia says there are different numbering systems within the city. You wacky left-coasters.

Boston: I’m not saying things are so much neater over here. Boston and presumably much of New England keep it simple. Numbers just count upward from the beginning of the street, wherever that may be. (I’m not actually sure which end of the street is favored for the beginning; I know my street in Cambridge starts from the north.) Being the jumbled mess that it is, Boston doesn’t have a whole lot of streets that are longer than a couple of blocks, hence a mostly purple map.

Is this what taxi drivers’ brains look like?

Until further notice, 2 million people in greater Boston must boil tap water before it’s safe to drink. But right there in the middle, we happily continue to drink cool, clean water in Cambridge, which has its own separate water supply.

This is all due to Saturday’s break in a massive pipe that carries water into the Boston area, prompting the use of emergency non-potable supplies from reservoirs and triggering aquapocalypse as people raided stores for bottled water, made endless jokes about drinking beer instead or brushing teeth with a bottle of Jack, and found themselves without their Dunkin’ Donuts coffee. (Seems some people freaked out instead of just boiling their water. But maybe it still tastes nasty after boiling. I wouldn’t know here in Cambridge, suckers!)

Directions Magazine’s Adena Schutzberg, who also lives in the area, has written a bit about the geography lessons of the incident and current situation.

The map above was, naturally, born in indiemapper.

The best way to get to know indiemapper is to head over to indiemapper.com, sign up, and try it for yourself. Nevertheless, in the interest of spreading the gospel of indiemapper, I present here a basic tour of its cartographic features.

Indiemapper is in part a reaction to the frustration, confusion, and difficulty we (as cartography students, teachers, and practitioners) have encountered in using GIS for thematic mapping. Our most important principle, which I hope is visible in the image above, is simple clarity—being easy to learn, easy to understand, and easy to use. Ben Sheesley and Mark Harrower have worked tirelessly to design an interface that fits that bill. Notice that the whole thing consists of only a half dozen or so components, the most complicated of which is the layers panel on the left side (which is a real feat of Flex/AS3 wizardry by Zach, I must add), and even that can be mastered with minimal effort.

GEOGRAPHIC DATA

We expect that most people want to map their own data, which can be uploaded from shapefiles, KML, and GPX files. To help you get started or to augment your own data, indiemapper is also stocked with reference data from Natural Earth vector and some pre-styled world reference base maps designed by Ben in indiemapper itself.

MAP PROJECTIONS

Map projections. Such pain they have caused me. But that’s a tale for another day. We ended up with fourteen projections that are a good selection of map projections suitable for most purposes. You have control over centering and standard parallels, and importantly the options are presented along with guidance and detailed information on what geometric properties each projection preserves and for what purposes the projection is appropriate.

MAP TYPES

Indiemapper has twelve basic types of thematic and reference map types, with more to come in the future. Here’s a quick rundown.

Reference points, lines, and areas. Any data source can have one or more layers depicting the base geography, and these can be combined to make some pretty nice reference maps, as you can see above in one of Ben’s base maps.

Choropleth. The bread and butter of thematic cartography. Indiemapper provides the excellent ColorBrewer color schemes and equal interval, quantile, and optimal breaks classification presets (or unclassed maps!).

Proportional symbols. These can be created for point features or on area feature centroids. They can either be unclassed (i.e. truly proportional), or classed, a.k.a. “range-graded” or “graduated.” Proportional symbol maps can get messy, but don’t worry, you can move the symbols around on the map so they don’t overlap.

Dot density. Our dot density maps simply place dots at random within polygons. Be careful with dot density maps—they’re not effective with all arrangements of enumeration units, and remember to always use an equal-area map projection!

Cartogram. Here we get into pretty interesting territory. Zach built in his code for non-contiguous cartograms, and I’m not aware of any similarly easy implementation of cartograms in mapping software. Contiguous cartograms are a challenge we may take on some day, but you can make some pretty sweet (and easier to read, I’d say) maps with non-contiguous cartograms. As with proportional symbols, you can move the cartogram polygons around, and usually you’ll want to do so. Zach has gone experimental and allowed for classed cartograms here, too.

Map labels. Any cartographer will agree that labeling is a huge part of the work that goes into a map and that automated label placement is a beast that has only recently been tamed. Indiemapper gets you started with basic labeling using any attribute you choose, and then allows you to move and rotate labels as desired. You have access to all the fonts installed on your computer, as well as a selection of embedded free fonts. Ben, whose PhD is practically in map typography, has made some templates based on his TypeBrewer work, making it easy to select effective and harmonious styles.

Bivariate choropleth. This is kind of a big deal. As far as I know, indiemapper makes creating bivariate choropleth way easier than ever before. It offers several sequential and diverging color schemes, automatic or manual (or no) classification, and a scatterplot to view the relationship between attributes.

Bivariate proportional symbols. Thanks to the flexible architecture that Zach programmed, it is very easy for us to combine symbology types, so a bivariate proportional symbol map is as simple as combining a proportional symbols with a choropleth-like color scheme. Note that the styling panel essentially places the two individual style panels into two tabs.

Bivariate cartograms. Again, we just combine two existing symbologies. These colored cartograms are really the best use of cartograms, showing some attribute on a perfectly equalized base map. We’ve all seen them following elections.

Value-by-alpha. This is an Axis Maps original. It’s a bivariate technique that I kind of made up in reaction to election cartograms, that was presented in our alternative election map, and was more fully developed by Robert Roth, me, and Zach in a forthcoming paper in the Cartographic Journal. One attribute is displayed by color, and another standardizing attribute by transparency. Some day I’ll finally write a post describing our work on the value-by-alpha technique.

Proportional labels. You see this kind of map occasionally, where labels are scaled according to some attribute value, a bit like in a word cloud. It was easy to implement, so why not?

Colored proportional labels. That’s right, we have a trivariate map symbology! It says one thing, is scaled by another thing, and colored by a third.

MAP LAYOUT

The goal of using indiemapper is to generate some sort of output image such as this Cartography 101-style map of Michigan (as vector SVG or raster JPEG and PNG), so layout controls are always available. At the center of the stage is a page that contains what will be exported in the end, and which has some style options of its own. On top of the map are several layers in a “Layout Objects” group: legends, north arrow, and annotations. Legends are generated automatically when you create a thematic layer, and they can be toggled on or off. North arrow options are, I’m sad to say, lacking dozens of garish styles. The annotation layer allows you to manually enter text for titles, labels, or what have you.

EXPERT GUIDANCE

As with the map above, there is additional information behind “learn more” buttons all over the place in indiemapper. There’s more to learn about every map type and many other features. Mark Harrower, building on his experience teaching and studying cartography as a professor at the University of Wisconsin-Madison, has written an extensive set of these “learn more” articles that teach users about cartography topics while providing guidance on best practices and how to achieve them in indiemapper. Among other things, this is one reason we think that indiemapper can be a very useful tool for students and teachers.

MAP MANAGEMENT

Save your maps online (unlimited storage), roll back to previous versions so you don’t have to worry about accidentally destroying your work, share your maps with other indiemapper users if you want to collaborate, and attach comments to map versions. Dave Heyman has built a fantastic web site and database back end to indiemapper that allows all this and so much more. It’s easy to manage all your maps from the “My Indie” page. Mark has recorded a nice video tour of all these features.

GET YOUR FACE IN THERE

Indiemapper.com. Get in there! You’ll get a 30 day free trial, and then it’s $30/month ($20 if you’re a student) with no lengthier commitments. Or you can stick to a weaker free version like a loser. You’re not a loser, are you?

In the past I have mentioned here an ongoing project to trace my every movement on a map, using memory and mouse-clicking rather than technology that costs money. Well, the advent of 2010 marks a full calendar year of doing this and a good moment to show some results.

Obviously this is not a novel concept (to choose a single example, I must link to UrbanTick here), and nobody besides me cares about the particulars of my travels. Shut up, it’s fun anyway. There are two reasons why this originally sounded interesting. First, I work from home, and there is very little routine in my trips out of the house, both in timing and destination. Rather than a predictable daily grind, I could hope for a an unknown awesome-looking pattern. Second, I keep the tracks separated by mode of transportation (foot, car, train, bus, and bike so far). A portrait of urban mobility or some such. As I bonus I will add that for a urban geography and cartography nerd, this project works as motivation to get out and explore different parts of town. There are witnesses to my excitement over being able to add a new line to the map.

Anyway, below is a little Flash animation of daily travels, with some transparency to highlight hot spots. I gave up on trying to do this beyond the immediate local area (Cambridge, Massachusetts)*, so there are some noticeable pauses where I disappeared for weeks on various out-of-town trips.

Goals for 2010:

• Cover more ground! I still haven’t made it to half of Cambridge, and there is a lot of neighboring Boston and Somerville to explore.
• Use a bicycle more than four times in a year. It is perhaps the best way to get around town and shouldn’t be collecting dust.
• Collect more data, such as distance, for summary statistics. This may require more sophisticated techniques than simply drawing lines, though, which would conflict with my New Year’s resolution to be more technologically lazy.

* Sorry for making this an increasingly Boston-centric blog, but hey, for your own projects you start with what’s outside your front door too, right? Not that I actually have a front door.

I have been learning my way around the Boston area for some fifteen months now, and I do not wish to suggest that the challenge in an urban area measures up to what the good people of rural Maine face, but I think of the phrase often as I’m puzzled by how to drive between two points in town. Compared to most American cities, the street network here can be rather chaotic, and absurdly simple trips like driving across a street or around the corner can require a convoluted route and an intimate knowledge of the local streets. It’s just another good reason to leave the car at home.

Anyway, while spending some time dreading getting in the car to finish a bit of Christmas shopping, I was curious to see what some of these ridiculous routes look like on a map. Here are a few of the not-so-simple paths required for simple trips in and around Boston. Bits of intersecting streets are shown to illustrate that there’s no such thing as just going around the block.

Bring GPS.

Made with indiemapper. We’ll probably return the map projection code to normal before it’s released.

Don’t say something like “white,” smartass. But don’t say “crimson” just yet, either.

This being a blog about maps, I of course mean Harvard not as a school but as a geographic entity. What color is the landscape, physical and cultural? When people look around at whatever interests them, what colors are they looking at?

I came up with one way of answering that. Here’s my logic, if it makes sense:

1. People take photos of what interests them.
2. Photos typically contain colors.
3. Flickr has many thousands of geotagged photos in the vicinity of Harvard.

After a few API calls and some code and graphics work, I’ve got a map showing the colors of the physical-cultural landscape around Harvard Square. This is not simply a map of the colors on the ground, which you can get from an aerial photo or systematic documentation like Google Street View, but rather a map of the colors that people on the ground are looking at.

Turns out crimson may be about right, as there’s a lot of red here. But that has less to do with Harvard and more to do with the fact that there is a lot of brick around here. The grass and trees of Harvard Yard are doing all they can to turn the map green in that area and only coming up with something yellowish.

As with much of what I post here, Harvard Square is of course merely a convenient and familiar local cartographic test subject, being just up the street from my home. Here’s another one, Boston Common. Lots of green in the park areas, red and orange in the Beacon Hill neighborhood (bricks again), and kind of blue (sky?) around the state capitol building.

Anyway, WTF is going on here? Quite simply, I’ve grabbed about 2,000 photos in each location from Flickr, determined the dominant color in each, mapped those colors, and interpolated liberally. Here are some dirty details.

Flickr API
These maps are based on the most recent 2,000 or so photos uploaded to Flickr and geotagged within the specified bounding box. This is easily accomplished with the flickr.photos.search request. Now, it would be wonderful to make a silly little web app that draws these maps on the fly, but the next step makes it pretty impractical. That is downloading 2,000 images. Even at the “square” (75×75) size, it takes a while.

Dominant color
Here things are fudged a fair amount. I tried a number of ways of simplifying a photograph down to a single representative color. The most obvious option is to calculate the average color, that is, combine the average red, green, and blue values into one color. But too often that results in a dull grayish color because there is too much color variety in the image. Next I tried the color that appears most frequently. It was sometimes better but also frequently just some dark unsaturated color. Then I looked at histograms and combined the most common red, green, and blue values into a single color. That was hit-or-miss and often produced a color that was not representative of the image at all. After a few other attempts, I decided to simplify a lot: get the average color, but only be concerned with the hue; keep it saturated and fairly bright. As such the maps are showing much stronger colors than most photos actually contain, and they poorly represent the occasionally unsaturated photo, but this seemed like the best way to get a set of very general overall colors. Here’s an example of three basic color options, using one of my own photos of a lovely summer day in the Boston Common; the bottom green color seems most representative and is what I’m using on the map.

Mapping the colors
Easy. Just draw a little square at the location of each photo. Here’s the Boston Common.

Sometimes there are multiple photos tagged at the exact same location, however. This time I was lazy and did not take that into account, so the color displayed at such a point is simply that of the last photo to be loaded there. I decided it wasn’t too big a deal given the many other points on the map.

Interpolating
Both of these map extents have thousands upon thousands of geotagged photos within them, but the locations are not at all evenly distributed. To get something more than clustered dots, I employed an interpolation method known as “blurring the crap out of them in Photoshop.” Generally colors fade nicely into one another, but these maps do display some colors that are largely artifacts of the blurring. Still, it works pretty well. I’m sure everyone recognizes the image below as Boston, right? (A shiny nickel to anyone who can explain why Allston-Brighton is so strongly blue/purple, so that I don’t have to go over there and find out for myself.)

In conclusion, call this stuff a work in progress, as I’d like to pursue it further, maybe just because looking at trippy images is fun. There must be a lot of locations that would produce interesting maps. Suggestions?