Videos in the Flickr API: Part Deux

We hope it’s obvious that long photos are taken extremely seriously here at FlickrHQ. To that end, it’s important that videos be first class citizens in our api. And with today’s launch of video for free users and the HD output, we have some important new api changes to share with you. So if you’re an uploader developer, a mobile application developer, or you make those things that are changing the way that people consume their tv and other media (nudge-nudge Boxee), take a look at these new additions to the api and make our long photos feel right at home in your apps.

With the addition of our HD output, all videos are now transcoded into 2 or 3 MP4s. Since these are in a widely-supported format, we thought it would be interesting to make them available to third-party developers. flickr.photos.getSizes will give you semi-permanent urls to the 700k site output, the mobile-optimized output, the 2mbps HD output (if available), and the original video (if the call is authenticated by the video owner and the owner is a pro member). For example:

<rsp stat="ok">
<sizes canblog="1" canprint="1" candownload="1">
<size label="Square" width="75" height="75" source="http://farm4.static.flickr.com/3436/3232057393_815b1c5d26_s.jpg" url="http://www.flickr.com/photos/mylesdgrant/3232057393/sizes/sq/" media="photo"/>
<size label="Thumbnail" width="100" height="56" source="http://farm4.static.flickr.com/3436/3232057393_815b1c5d26_t.jpg" url="http://www.flickr.com/photos/mylesdgrant/3232057393/sizes/t/" media="photo"/>
<size label="Small" width="240" height="135" source="http://farm4.static.flickr.com/3436/3232057393_815b1c5d26_m.jpg" url="http://www.flickr.com/photos/mylesdgrant/3232057393/sizes/s/" media="photo"/>
<size label="Medium" width="500" height="281" source="http://farm4.static.flickr.com/3436/3232057393_815b1c5d26.jpg" url="http://www.flickr.com/photos/mylesdgrant/3232057393/sizes/m/" media="photo"/>
<size label="Original" width="1280" height="720" source="http://farm4.static.flickr.com/3436/3232057393_204af3bcff_o.jpg" url="http://www.flickr.com/photos/mylesdgrant/3232057393/sizes/o/" media="photo"/>
<size label="Video Player" width="640" height="360" source="http://www.flickr.com/apps/video/stewart.swf?v=1233362721&photo_id=3232057393&photo_secret=815b1c5d26" url="http://www.flickr.com/photos/mylesdgrant/3232057393/" media="video"/>
<size label="Site MP4" width="640" height="360" source="http://www.flickr.com/photos/mylesdgrant/3232057393/play/site/815b1c5d26/" url="http://www.flickr.com/photos/mylesdgrant/3232057393/" media="video"/>
<size label="Mobile MP4" width="480" height="360" source="http://www.flickr.com/photos/mylesdgrant/3232057393/play/mobile/815b1c5d26/" url="http://www.flickr.com/photos/mylesdgrant/3232057393/" media="video"/>
<size label="HD MP4" width="1280" height="720" source="http://www.flickr.com/photos/mylesdgrant/3232057393/play/hd/815b1c5d26/" url="http://www.flickr.com/photos/mylesdgrant/3232057393/" media="video"/>
<size label="Video Original" width="1280" height="720" source="http://www.flickr.com/photos/mylesdgrant/3232057393/play/orig/123fakest/" url="http://www.flickr.com/photos/mylesdgrant/3232057393/" media="video"/>
</sizes>
</rsp>

Use this if you’re lazy. If you’re not lazy and want to be one of the cool kids, you can construct the urls to these outputs yourself, assuming you have the nsid or custom url of the owner, the video id, and the secret (or original secret). Requesting the HD output for a video that doesn’t have it (because it’s less than 720 pixels high, or the owner is a free member), will deliver a 404. An example url:

http://www.flickr.com/photos/{user-id|custom-url}/{photo-id}/play/{site|mobile|hd|orig}/{secret|originalsecret}/

If you’re developing uploading tools for free users, flickr.people.getUploadStatus has new attributes to determine whether a user is allowed to upload any more videos or not. If the user is a free user, the output of this method will now look something like this:

<rsp stat="ok">
<user id="88251462@N00" ispro="0">
<username>Dev Myles</username>
<bandwidth max="107373568" used="0" maxbytes="104857600" usedbytes="0" remainingbytes="104857600" maxkb="104857" usedkb="0" remainingkb="104857" unlimited="0"/>
<filesize max="10485760" maxbytes="10485760" maxkb="10240" maxmb="10"/>
<sets created="7" remaining="lots"/>
<videosize maxbytes="157286400" maxkb="153600" maxmb="150"/>
<videos uploaded="0" remaining="2"/>
</user>
</rsp>

Note the new <videos> element in the response, which will let you know how many more videos this user can upload this month.

And as always, if you feel like we’re missing something, please let us know.

Machine Tag Hierarchies

Untitled Compass #1228516024

something:somethingelse=somethingspecific

With apologies to Jeremy Keith

If you’re not already familiar with machine tags the easiest way to think of them is being like a plain old tag but with a special syntax that allows users to define additional structured data about that tag. If you’d like to know more, the best place to start is the official announcement we made about machine tags in the Flickr API group.

If you want to know even more, still, take a look at:

Okay! Now that everyone is feeling warm and fuzzy about machine tags: We’ve added (4) new API methods for browsing the hierarchies of machine tags added to photos on the site. These are aggregate rollups of all the unique namespaces, predicates, values and pairs for public photos with machine tags.

For example, lots of people have added exif: related machine tags to their photos but there hasn’t been a way to know what kind of EXIF data has been added: exif:model? exif:focal_length? exif:tunablaster? Or what about all the planespotters who have been diligently adding machine tags to their photos using the aero namespace: What are the predicates that they’re tagging their photos with?

Those are the sorts of things these methods are designed to help you find. Sort of like wildcard URLs but for metadata instead of photos. Uh, sort of.

Untitled Future #1223665161

Anyway, the new methods are:

flickr.machinetags.getNamespaces

This returns a list of all the unique namespaces, optionally bracketed by a specific predicate. For example, these are all the namespaces that have an airport predicate:

# ?method=flickr.machinetags.getNamespaces&predicate=airport

<namespaces predicate="airport" page="1" total="2" perpage="500" pages="1">
	<namespace usage="1931" predicates="1">aero</namespace>
	<namespace usage="3" predicates="1">geo</namespace>
</namespaces>
		

flickr.machinetags.getPredicates

Like the getNamespaces method this returns a list of all the unique predicates, optionally bracketed by a specific namespace. For example, these are all the predicates that use the dopplr namespace:

			
# ?method=flickr.machinetags.getPredicates&predicate=dopplr

<predicates namespace="dopplr" page="1" total="4" perpage="500" pages="1">
	<predicate usage="4392" namespaces="1">tagged</predicate>
	<predicate usage="1" namespaces="1">traveller</predicate>
	<predicate usage="7780" namespaces="1">trip</predicate>
	<predicate usage="4269" namespaces="1">woeid</predicate>
</predicates>
		

flickr.machinetags.getValues

At this point, the pattern should be pretty straightforward. This method returns all the unique values for a specific namespace/predicate pair. For example, these are some of the values associated with the aero:tail machine tag (yes, really, airplane tail models!):

# ?method=flickr.machinetags.getValues&namespace=aero&predicate=tail
		
<values namespace="aero" predicate="tail" page="1" total="1159" 
	perpage="500" pages="3">
	<value usage="1">01-0041</value>
	<value usage="1">164993</value>
	<value usage="2">26000</value>
	<value usage="1">4k-az01</value>
	<value usage="1">4l-tgl</value>
	<value usage="1">4r-ade</value>
	<!-- and so on... -->
</values>
		

flickr.machinetags.getPairs

Finally, the getPairs method returns the list of unique namespace/predicate pairs optionally filtered by namespace or predicate.

Rather than including yet-another giant blob of XML, here’s a pretty picture of the metro stations in Munich instead:

ubahn

A few things to note

Certain namespace/predicate pairs have been special-cased to return a single value. As of this writing they are:

  • geo:lat (and variations)
  • geo:lon (and variations)
  • file:name
  • file:path
  • anything:md5

If people have particular reasons for needing or wanting these we’re open to the idea but otherwise the cost of storing all the variations and the dubious uses for returning them in the first place made us decide to exclude them.

Now what?

Some people take sandcastles pretty seriously...

photo by Daveybot

Well, that’s what we’re hoping you’ll tell us. Machine tags have been chugging away quietly since we announced them almost two years ago and despite being a bit nerd-tastic and awkward to explain we’ve been thrilled to see how people have been finding their own use for them.

And the list goes on.

The trick with machine tags has always been to make them both invisible (or at least barely visible) to those people who don’t care about them but also as easy as tags to pick up and use for those people who do or who wonder whether they might be the tool they were looking for. One thing we didn’t do very well, though, until the release of the machine tag hierarchy APIs was give people a way to learn about machine tags. The only way to find out which machine tags people were using was to hop-scotch your way around people’s photostreams or to be part of a larger community having a discussion about which tags to use. Oops.

Which is why it was extra-fantastic when a few short days after we announced the machine tag hierarchy methods on the API list, the ever prolific and awesome Paul Mison wrote back and said:

The obvious thing to build on top of these … is some sort of graphical machine tag browser, a bit like the Mac OS X / iPod column view browser. So I did.

http://husk.org/code/machine-tag-browser.html

This is entirely self-contained in one file (except for loading jQuery from Google and (cough) the pulser from Flickr). It uses JavaScript to get a full list of namespaces, giving you the option to drill down into predicates and the values available for that namespace/predicate pair.

We’re hoping that this provides a little more raw material to play with and maybe find some magic and that you’ll tell us what comes next.

Yay!

Oh yeah, the actual API methods

Enjoy!

In the coming weeks we’ll also try to gather most of the blog posts and other writings about machine tags and put them with the rest of the API documentation.

5 Questions for Gustavo

Following our second interview Kellan snuck in 5 Questions for Paul Mison before I managed to tap Jim’s suggestion of Gustavo.

I think Drift Words sums Gustavo up nicely with “Although he’s far too clever, he makes up for it by using his polymath powers for good.” … and charts and stunning graphs. It’s always a pleasure to see what Gustavo comes up with.

And on that note …

1. What are you currently building that integrates with Flickr, or a past favorite that you think is cool, neat, popular and worth telling folks about? Or both.

Gustavo: First of all I must say: I’m not really a flickr tool developer. The only real tools I created are the quite minimalistic FlickRandom and Contact Crossing (very kindly hosted by Jim Bumgardner). Rather, I use flickr’s API to mine flickr’s database for interesting information, usually leading to some visualizations or at the very least a bunch of graphs.

The FlickrVerse, April 2005 poster: flickr's social network

One such visualization led to a browser for exploring related groups. Not a full-fledged tool since it explores static and outdated data.

In other words, what I do with flickr’s API is not tool development but analyses, trying to figure out the structure and dynamics of flickr’s social network, group content and participation, etc. The most recent analysis I performed attempted to understand how exposure to photo content flows through the contact network. Starting from a basic pattern combining three types of network relations, I quantified the importance of a user’s social network in determining his or her exposure to content of interest.

2. What are the best tricks or tips you’ve learned working with the Flickr API?

Gustavo: Cache, cache, cache. Depending on what you want to do, you might find yourself retrieving certain bits repeatedly, and you’ll definitely want to build a good local cache. Be careful though, as it’s all too easy to underestimate the size and complexity of the data. Your cache might unexpectedly morph from a speed asset to a sluggish monster.

Another potential problem from underestimating the size and complexity of the data is that you might suddenly discover that your code issued many more API calls than you expected. Remember to play nice, and keep an eye on your API key usage graphs.

Expect unexpected responses: It’s always good to make the code smart enough to realize the server’s response is not exactly what was expected, be it in completeness, format, special characters in free text, etc.

Finally, still on the theme of unexpected responses: Grow a thick skin, as there will always be someone who will misinterpret your motives for developing a tool that “uses” their information.

3. As a Flickr developer what would you like to see Flickr do more of and why?

Gustavo: Let me suggest two: one very simple, the other very complex.
The simple one is a “no special perms” authentication level. For some purposes, as a developer I’d like to have the user authenticate for the sole purpose of knowing who they are – I might want to give certain results for their eyes only, or someone else might want to allow certain actions to happen just once per user, etc. At the moment, the minimal level of authentication requires that the user entrust the developer with access to private data. Many users will rightfully decline giving such access, and as a developer I’d rather not have to even request and disclaim, when I don’t need it.

The more complex one requires a bit of background. Almost four years ago, there were various discussion threads on the topic of finding interesting content. Back then I took a stab at using network information to discover interesting photos – first looking for people who post similar stuff, then looking for people who share faved photos (which striatic called neighbors) and finally, actual photo suggestions.

neighbors

As an aside, the algorithm worked quite well even for people with a hundred or so favorites (I had just 21 faves!); people today have many thousand favorites – a very rich data set to start from. I went on to produce suggestion lists for many people, but that was always me, manually running scripts. Since then, other developers created interesting tools for content-driven content discovery, including Flickr Cross-Recommendations, inSuggest and flexplore.

flexplore 2.1 beta

The reason I never tried to create a stand-alone tool for this is that I quickly realized that to make it work reasonably fast, I essentially needed to replicate flickr’s database. If you take all my favorites, then list all the people that faved those photos, and finally enumerate all their favorites… and you then repeat this exercise for whoever requests it, you either need to use many thousand API calls per visitor (and wait!), or you need to create a huge cache, covering unpredictably disparate segments of flickr’s database. A massive cache that would grow stale very quickly unless people used the tool continuously. If you try to include extra information into the scoring scheme (say tags, color data, group membership…) the network use and storage requirements grow even worse. In other words, this project appears to be completely unsuitable for a developer without direct access to flickr’s database… and flickr’s content suggestion system (Explore) doesn’t provide any personalization tools: we all see the same.

The only effective solution I can suggest (beyond flickr developing a personalized Explore, or flickr sandboxing third party developers) is the creation of high level API calls, embodying some method of complex querying into the database. For example: A higher level API call could accept a list of users as query, and return a list of photos sorted by the number of people (from the query list) who faved them. With the current API, one has to retrieve the full favorites list for each person, collate the results, and discard the vast majority of the information that was transferred. A higher level API method could make such intermediary results invisible and save much bandwidth, latency and data replication.

Hey, you asked. ;)

4. What excites you about Flick and hacking? What do you think you’ll build next or would like someone else to build so you don’t have to?

Gustavo: There’s a number of things that attract me to flickr hacking. There’s of course the vast and ever-growing amounts of data, and the fact that it’s not “more of the same”: The diversity of data types (photos, users, metadata, groups, etc) and relations make this complex system fascinating to study. There is also the human side: People really care about their stuff. People get excited, for example, when they recognize their user icon in a visualization of the social network, and immediately want to explore around. Last but not least, I really appreciate the openness of the flickr API. I’m amazed that such wealth of information is shared so freely!

Free association, first page

As for “what next”, I have a couple of ideas. I’ll only hint that the word association analysis was a fun first step. :)

5. Besides your own, what Flickr projects and hacks do you use on a regular basis? Who should we interview next?

Gustavo: dopiaza as Utata‘s architect.

Dan: Thank you, Gustavo. Next up (unless Kellan gets in first!) dopiaza.

Images from GustavoG,
striatic and malanalars.

5 Questions for Paul Mison

One of the key goals for this blog when we launched it 9 months ago was to be a channel for the voice of the Flickr development community. Most importantly all the amazing developers building on our APIs. Which is by way of introducing our third developer interview here at code.flickr, our first was with Neil Berkman of Photopholow, while our 2nd, and first in the 5 questions format was with Jim Bumgardner a few weeks ago.

We’ll be posting an interview from GustavoG (as tapped by Jim) soon, but in the mean time I want to post an interview from Paul Mison aka blech. Paul is an active participant in the Flickr API group, and I’ve personally been using and loving his new project SnapTrip. And he likes rainbows, which makes him good by us.

A Trip Underground

1. What are you currently building that integrates with Flickr, or a
past favorite that you think is cool, neat, popular and worth telling
folks about? Or both.

Paul: My current main project is snaptrip, which works with Dopplr, a website for sharing personal travel information, as well as with Flickr. It helps you to find photos associated with a trip listed in Dopplr, to label them so that Dopplr can find them easily later on, and also lets you geotag them (if you haven’t already). I’ve also written a Greasemonkey user script so that you can see when other people’s photos were taken during a Dopplr trip.

Flickr photos in snaptrip

In the past I’ve mainly written command line tools; I used a script to migrate images out of my previous home-brewed image hosting to Flickr, and I have another that applies machine tags for EXIF properties (since tags make it easy to find photos; here’s all my photos with a focal length of 50mm). My great lost project was a web application called groupr that would let you see all the photos in groups you’re a member of, but unfortunately the platform I built it on was withdrawn, and I should rebuild it elsewhere (possibly on Google’s App Engine, like snaptrip; possibly not).

2. What are the best tricks or tips you’ve learned working with the
Flickr API?

Paul: The API Explorer is wonderfully useful, and it should be everyone’s first port of call when developing an application. Beyond that, I’d advise picking an API framework that does the tricky things (notably, user authentication – I’ve handcoded it myself, and it can be fiddly), but otherwise gets out of your way.

snaptrip uses Beej’s Python Flickr API, and I’ve previously used flickraw (for Ruby) and Flickr::API (for Perl). All three are nice and minimal, so that when new API methods are added, you don’t have to update your library. flickraw uses JSON internally, too, which is very nice if (like me) you lean towards dynamic, rather than static, languages.

For Greasemonkey scripts, this post from mortimer? about using API calls in GM scripts is great.

3. As a Flickr developer what would you like to see Flickr do more of
and why?

Paul: Well, a relatively minor request would be for JSON in the API Explorer. More seriously, there’s an entire class of methods I wish existed for groups. For example, the only way to track conversations at the moment is the group RSS feed, which isn’t segregated by thread. There’s no way to find out a group’s administrators or moderators. A final example is that the queue of photos awaiting approval isn’t exposed to the API. While I’m not sure I’d have used all of these in groupr, some of them would have been very handy.

Another small request would be for more extras, especially a few method-specific ones. In particular, I’d love to see ‘favedate’ on flickr.favorites.getPublicList.

4. What excites you about Flickr and hacking? What do you think you’ll
build next or would like someone else to build so you don’t have to?

Paul: For all that my answer to the last question was a demand for more methods, Flickr is exciting both because of the wealth of photography there, and the richness of the methods of getting at it. The geographical data, and access to it, that has emerged over the last year is really interesting, and I’d love to do something with it (and intend to, somehow, in snaptrip). However, for a complete new project, I’ve been poking for a year or so at making your Flickr favourites look a bit nicer, and maybe within another year I’ll actually have something out publicly. (I really need a simple job queue; anyone?)

5. Besides your own, what Flickr projects and hacks do you use on a
regular basis? Who should we interview next?

Paul: Well, as a Mac user, I’m a fan of Fraser Speirs Flickr Export for getting my images onto the site in the first place, and if I upgrade to an iPhone I look forward to playing more with Exposure. On the web, Dario Taraborelli’s Group Trackr is very nice, and I use fd’s Flickr Scout every now and again to see if anything’s hit Explore.

However, I think the most impressive recent project I’ve seen is a desktop app written using Adobe’s Air, called Destroy Flickr, by Jonnie Hallman. There were a lot of subtle UI techniques to hide the latency inherent in talking to a network service, so I think he’d be a great choice for an interview.

Kellan: Thanks Paul! And y’all be looking out for an interview with Jonnie and his oddly named project.

5 Questions for Jim Bumgardner

We’ve been keeping a careful eye on our Sister Blog to see what they’re up to. Something that’s particularly caught our eye is "5 Questions ", asking the same 5 questions to the Flickrverse, with the last question being who we should ask next. And so, we hope, it goes on and on.

Banana-bub

This is our version, asking questions of those that develop, hack and fiddle with Flickr in new and interesting ways. Of course we couldn’t start with anyone else but KrazyDad (aka Jim Bumgardner).

Jim founded the Flickr Hacks group back in the day, a great place to hang out and ask question if you want to learn how to bend Flickr to your will. In 2006 he also coauthored the Flickr Hacks book for O’Reilly and happily for us he hasn’t stopped tinkering with Flickr yet.

So, without any further ado, 5 Questions for Jim Bumgardner:

1. What are you currently building that integrates with Flickr, or a past favorite that you think is cool, neat, popular and worth telling folks about? Or both.

Jim: It seems like I’m always building something that integrates Flickr. A recent favorite is this interactive mosaic that shows the most interesting photos of the week.

The photos are arranged to form a spiral, a form that appears quite frequently in my work.

www.coverpop.com/pop/flickr_interesting
Coverpop: Most Interesting Photos of the Week

I have a "cron job" which runs on one of my computers at home, which updates this mosaic every week, so the photos in it are always fresh. Incidentally, I prefer to call this process a "cron joy." Oh, nerd humor…

2. What are the best tricks or tips you’ve learned working with the Flickr API?

Jim: I think every Flickr hackr should have access to a powerful high level
graphics library. My library of choice is ImageMagick combined with the Perl programming language (it also works nicely with Ruby), but the GD library, which works with various languages, and PIL, for Python, are also good.

I not only use ImageMagick for building mosaics and graphs, but also for "under the hood" kinds of things, like measuring the average colors of photos for the Colr Pickr (see below).

3. As a Flickr developer what would you like to see Flickr do more of and why?

Jim: One of the very first Flickr hacks I made was the Colr Pickr

www.krazydad.com/colrpickr/

…which allows photos to be selected by color. Since that appeared, I’ve worked on, and seen some fancier variations on the concept, that allow larger quantities of Flickr photos to be selected using multiple colors. But all these systems, require that thousands or even millions of thumbnails be downloaded and analyzed for color. This is because Flickr does not supply "average color" information in its APIs, and cannot provide the color search functionality that this data would enable.

flickr Colr Pickr

I would like to see Flickr provide, via it’s APIs, the three most common colors in each photo (using cluster analysis), and provide a way to search for photos which match one, two, or three colors. These parameters, similar to geocode searches, would need to be combined with some other search parameters, such as tags, to narrow
the field down.

A feature like this would be a godsend to designers. I’ve got sample code for the color analysis, if anyone’s interested… :)

4. What excites you about Flick and hacking? What do you think you’ll build next or would like someone else to build so you don’t have to?

Jim: One thing that excites me is the ability to access large quantities of photos that contain valuable metadata, such as the time the photo was taken, or the geocoded location. I used the ‘date taken’ data to construct this very cool graph of sunsets:

A year of sunsets

While most digital cameras store the time within photos, these days, not enough of them automatically store the location. We have to rely on photographers adding the geocoded information manually, and sadly, not enough of them are geeky enough to do it. I’m looking forward to the day, a few years from now, when most of the new photos on Flickr will also contain geocoded information, as this will enable me to make apps which enable a kind of instant photo-journalism of heavily photographed events, such as rallies and parades. We’re seeing the beginnings of these kind of apps now, but we’re barely scratching the surface.

5. Besides your own, what Flickr projects and hacks do you use on a regular basis? Who should we interview next?

mc-50 map of FlickrLand: flickr's social network

Jim: GustavoG has made some amazing graphs which exploit and illustrate the Flickr social network.

Dan: Thank you, Jim. Next up for our thrilling installment of 5 Questions, GustavoG .

Images from krazydad / jbum , earthhopper and GustavoG.

Who’s On First?

Untitled World View #1215585993

Normally we don’t talk about upcoming features but in recent weeks we’ve been hard-pressed to keep a lid on our renewed excitement for kittens. We’re betting 2009 will be a big year for kittens and it is why Dan and Heather are taking so much time to hash out the details for the new flickr.kittens API framework which we’re confident will re-embiggen-ize the how, the what and the why of photo-sharing!

To pass the time, until then, I’m going to talk about some of the geo-related API methods that have been released in the last few months, but perhaps not properly explained in detail and introduce a new minty-fresh method which hasn’t been discussed at all!

Cake for breakfast

First, the new stuff.

Places for a user

We’ve added a new authenticated method to the flickr.places namespace called flickr.places.placesForUser which returns the top 100 unique places, scoped by place type, where a user has geotagged photos. For example, I’ve geotagged photos in the following countries:

# ?method=flickr.places.placesForUser&place_type=country

<places total="7">
	<place place_id="4KO02SibApitvSBieQ" woeid="23424977"
		latitude="48.890" longitude="-116.982"
		place_url="/United+States" place_type="country"
		photo_count="1264">United States</place>
	<place place_id="EESRy8qbApgaeIkbsA" woeid="23424775"
		latitude="62.358" longitude="-96.582"
		place_url="/Canada" place_type="country"
		photo_count="307">Canada</place>

	<place place_id="3s63vaibApjQipWazQ" woeid="23424950"
		latitude="39.895" longitude="-2.988"
		place_url="/Spain" place_type="country"
		photo_count="67">Spain</place>
	<place place_id="6immEPubAphfvM5R0g" woeid="23424819"
		latitude="46.712" longitude="1.718"
		place_url="/France" place_type="country"
		photo_count="60">France</place>
	<place place_id="DevLebebApj4RVbtaQ" woeid="23424975"
		latitude="54.313" longitude="-2.232"
		place_url="/United+Kingdom" place_type="country"
		photo_count="34">United Kingdom</place>
	<place place_id="mSCQNWWbAphdLH6WDQ" woeid="23424812"
		latitude="64.950" longitude="26.064"
		place_url="/Finland" place_type="country"
		photo_count="24">Finland</place>

	<place place_id="mpa01jWbAphICsyCsA" woeid="23424853"
		latitude="42.502" longitude="12.573"
		place_url="/Italy" place_type="country"
		photo_count="8">Italy</place>
</places>

The response format is (almost) like all the other places methods, which I guess makes it a standard places response though we haven’t gotten around to standardizing it like we have with photos. Places responses will always contain a “place ID” and a “WOE ID”, a “latitude” and a “longitude”, a “place type” and a “place URL” attribute. They usually contain an “accuracy” attribute but it doesn’t make any sense in the a list of places for a user since the photos, clustered by place type, may have been geotagged at multiple zoom levels. In this example, we’ve also added a “photo count” attribute since that’s an interesting bit of information.

The list of place types with which to scope a query by is limited to a subset of the place types in the Flickr location hierarchy, specifically: neighbourhoods, localities (cities or towns), regions (states) and countries. While place_type is a required argument for the method, there are two other optional parameters you can use to filter your results.

Places for a user (and a place)

The first is woe_id and ensures that places of a given type also have a relationship with that WOE ID. For example, these are all the localities for my geotagged photos taken in Canada (WOE ID 23424775):

# ?method=flickr.places.placesForUser&place_type=locality&woe_id=23424775

<places total="5">
	<place place_id="4hLQygSaBJ92" woeid="3534"
		latitude="45.512" longitude="-73.554"
		place_url="/Canada/Quebec/Montreal" place_type="locality"
		photo_count="221">Montreal, Quebec</place>
	<place place_id="63v7zaqQCZxX" woeid="9807"
		latitude="49.260" longitude="-123.113"
		place_url="/Canada/British+Columbia/Vancouver" place_type="locality"
		photo_count="59">Vancouver, British Columbia</place>
	<place place_id="zrCws.mQCZj_" woeid="9848"
		latitude="48.428" longitude="-123.364"
		place_url="/Canada/British+Columbia/Victoria" place_type="locality"
		photo_count="9">Victoria, British Columbia</place>

	<place place_id="WzwcDQCdAJsL" woeid="4177"
		latitude="44.646" longitude="-63.573"
		place_url="/Canada/Nova+Scotia/Halifax" place_type="locality"
		photo_count="3">Halifax, Nova Scotia</place>
	<place place_id="XlQb2xedAJvr" woeid="4176"
		latitude="44.673" longitude="-63.575"
		place_url="/Canada/Nova+Scotia/Dartmouth" place_type="locality"
		photo_count="1">Dartmouth, Nova Scotia</place>
</places>

(Most) places for a user (and a place)

The second optional parameter is threshold which requires a place have a minimum number of photos associated with it in order to be included in the result set. Any place that falls below the threshold will be rolled-up in to its parent location. For example, if we search for localities in Canada but also a minimum threshold of 5 photos per location the towns of Halifax and Dartmouth are rolled up in to the province of Nova Scotia:

# ?method=flickr.places.placesForUser&place_type=locality&woe_id=23424775&threshold=5

<places total="4">
	<place place_id="4hLQygSaBJ92" woeid="3534"
		latitude="45.512" longitude="-73.554"
		place_url="/Canada/Quebec/Montreal" place_type="locality"
		photo_count="221">Montreal, Quebec</place>

	<place place_id="63v7zaqQCZxX" woeid="9807"
		latitude="49.260" longitude="-123.113"
		place_url="/Canada/British+Columbia/Vancouver" place_type="locality"
		photo_count="59">Vancouver, British Columbia</place>
	<place place_id="zrCws.mQCZj_" woeid="9848"
		latitude="48.428" longitude="-123.364"
		place_url="/Canada/British+Columbia/Victoria" place_type="locality"
		photo_count="9">Victoria, British Columbia</place>
	<place place_id="QpsBIhybAphCEFAm" woeid="2344921"
		latitude="44.727" longitude="-63.587"
		place_url="/Canada/Nova+Scotia" place_type="region"
		photo_count="4">Nova Scotia, CA</place>
</places>

Note that we only roll up a single level so if, like the Halifax and Dartmouth, a locality gets rolled up in to its parent region it may still have fewer photos associated with it than the threshold you passed with the method call. If you think this is crazy talk and/or have some other use case we haven’t considered with this model tell us why and we can revisit the decision.

Untitled Relationship #1219894402

Finally, as mentioned above the flickr.places.placesForUser method requires that you include an auth token with minimum read permissions. As always, please take extra care to respect people’s senstitivies when it comes to location data and, above all, don’t be creepy.

Meanwhile, back at the Ranch

About a week ago, I was asked whether it was possible to use the Flickr API to get a feed of geotagged photos (for a particular place/radius) sorted by interestingness, filtered by CC license to which I quickly replied: WOE IDs, the flickr.places APIs and the “radius” parameter in the flickr.photos.search method should get you what you need! (Also the API responses as syndication feeds support, if you’re being finnicky about the question.)

Which got me thinking that while we’ve told people about WOE IDs and the Places API we haven’t really made a lot of noise about the addition of radial queries and the has_geo flag to the flickr.photos.search method. We’ve mentioned it in passing, here and there, but never really tied it all together. So, let’s start with WOE IDs:

WOE (short for Where On Earth) IDs are the unique identifiers in the giant database of places that we (and FireEagle and the rest of Yahoo!) use to keep track of where stuff is. They are also available to you and the rest of the Internets via the public GeoPlanet API. In Flickr, every geotagged photo has up to (6) associated WOE IDs representing a neighbourhood, locality, county (if present), region, country and continent.

Geocoding

Using the example above, you could start with an API call to the flickr.places.find method which is like an extra-magic geocoder: It not only resolves places names to latitude and longitude coordinates but also returns the WOE ID for the place that contains it. Searching for “San Francisco CA” returns WOE ID 2487956 which you can use to call the flickr.photos.search method asking for all the photos geotagged in the city of San Francisco sorted by interestingness with a Creative Commons Attribution license. Something like this:

# ?method=flickr.places.find&query=San+Francisco+CA

<places query="San Francisco CA" total="1">
	<place place_id="kH8dLOubBZRvX_YZ" woeid="2487956" latitude="37.779"
       	longitude="-122.420" place_url="/United+States/California/San+Francisco"
       	place_type="locality">San Francisco, California, United States</place>
</places>

# ?method=flickr.photos.search&license=4&sort=interestingness-desc 
# 	&woe_id=2487956&extras=tags,geo,license


<photos page="1" pages="289" perpage="100" total="28809">
	<photo id="145874931" owner="37996593020@N01" secret="b695138626" server="52"
       	farm="1" title="bridge" ispublic="1" isfriend="0" isfamily="0"
       	tags="sanfrancisco bridge water night reflections geotagged lights
       	baybridge geolat3779274 geolon12239096 sfchronicle96hours
       	sanfranciscochronicle96hours" latitude="37.79274" longitude="-122.39096"
       	accuracy="16" license="4"
		place_id="kH8dLOubBZRvX_YZ" woeid="2487956"/>

	<!-- and so on -->
</photos>

Reverse geocoding

You can also lookup the WOE ID for any set of latitude and longitude coordinates. Imagine that you are standing in front the infamous Wall of Rant in San Francisco’s Mission district and you’d like to see photos for the rest of the neighbourhood.

Picture 1

If you know your geo coordinates you can call the flickr.places.findByLatLon method to reverse geocode a point to its nearest WOE ID which can then be used to call the trusty flickr.photos.search method. Like this (without the photos.search part since it’s basically the same as above):

# ?method=flickr.places.findByLatLon&lat=37.752969&lon=-122.420844

<places latitude="37.752969" longitude="-122.420844" accuracy="16" total="1">
	<place place_id="C.JdRBObBZkMAKSJ" woeid="2452334"
	    latitude="37.759" longitude="-122.418"
	    place_url="/United+States/California/San+Francisco/Mission"
	    place_type="neighbourhood"/>
</places>

Nearby

But what if you just want to see photos nearby a point? Radial queries, recently added to the photos.search method, allow you to pass lat and lon parameters and ask Flickr to “show me all the photos within an (n) km radius of a point”. You have always been able to do something like this using the bbox parameter but radial queries differ in two ways:

  1. They also save you from having to calculate a bounding box which is, you know, boring.
  2. Results are sorted by distance from the center point (you can override this by setting the sort parameter). Trying to do the same with a bounding box query would mean fetching all the results first and then sorting them which both expensive and boring and breaks the pagination model.

Radial queries are not meant for pulling all the photos at the country or even state level and as such the maximum allowable radius is 32 kilometers (or 20 miles). The default value is 5 and you can toggle between metric and imperial by assigning the radius_units parameter a value of “km” or “mi” (the default is “km”).

# ?method=flickr.photos.search&lat=37.752969&lon=-122.420844 
# 	&radius=1&extras=geo,tags&min_taken_date=2008-09-01+00%3A00%3A00


<photos page="1" pages="1" perpage="100" total="9">
	<photo id="2820548158" owner="29072902@N00" secret="b2fc694880" server="3288"
		farm="4" title="20080901130811" ispublic="1" isfriend="0" isfamily="0"
		latitude="37.751166" longitude="-122.418833" accuracy="16"
		place_id="C.JdRBObBZkMAKSJ" woeid="2452334"
		tags="moblog shinobu"/>

	<!-- and so on -->
</photos>

See that min_taken_date parameter? Like all geo-related query hooks in the flickr.photos.search method you need to pass some sort of limiting agent: a tag, a user ID, a date range, etc. If you insist on passing a pure geo query we will automagically assign a limiting agent of photos taken within the last 12 hours.

(I can) has geo

Finally (no, really) if you just want to keep things simple and use a tag search you can also call the flickr.photos.search method with the has_geo argument which will scope your query to only those photos which have been geotagged. For example, searching for all geotagged photos of kittens taken in tokyo:

# ?method=flickr.photos.search&tags=tokyo,kitten&tag_mode=all 
# 	&has_geo=1&extras=tags,geo

<photos page="1" pages="1" perpage="100" total="60">
	<photo id="2619847035" owner="27921677@N00" secret="0979aed596" server="3011"
       		farm="4" title="Kittens in Akiba" ispublic="1" isfriend="0" isfamily="0"
       		tags="japan cat tokyo kitten crowd akihabara unexpected"
		latitude="35.698263" longitude="139.771977" accuracy="16"
		place_id="aod14iaYAJ1rDE.R" woeid="1118370"/>

	<!-- and so on -->

</photos>

Maps are purrrr-ty

Which is a nice segueway in to telling you that on Tuesday we turned on the map-love for
the city of Tokyo, in addition to Beijing and Black Rock City (aka Burning Man), using the Creative Commons licensed tiles produced by the good people at Open Street Maps. We’re pretty excited about this but rather than just showing another before and after screenshot we decided that the best way to showcase the new tiles was with… well, kittens of course!

Picture 1

Sophie’s Choice by tenaciousme

Enjoy!

That’s a lot to digest in one go but we promise there won’t be a pop quiz on Monday. Hopefully there’s something useful for you in the twisty maze of possibilities, now or in an oh yeah, what about… moment in the future, and maybe even the seed for a brand new API application. Kittens!

Open! Hack! Day!

Once again Yahoo! is opening its doors to a horde of unwashed hackers. You should join us!

In case you missed last years Beck-filled extravaganza, Open Hack Day gives developers 24 hours to build a cool hack and demonstrate it to a packed audience and celebrity judges.

Better yet, some of the Flickr staffers will be on hand to answer any of your burning API questions and judge the Best Flickr Hack category (and yes, there are prizes).

Open Hack Day kicks off Friday with talks on Yahoo! APIs and technologies. Flickr-related talks include:

  • Getting Started with the Flickr API – Friday, Sept. 12 from 11:00am to 11:50am
  • Building a Purple Pedal GPS-Flickr Bike – Friday, Sept. 12 from 12:00pm to 12:50pm

It runs from Friday, Sept. 12 to Saturday, Sept. 13, at Yahoo! HQ in Sunnyvale, CA. If you’re interested, go to the Open Hack Day website to register.

API Responses as Feeds

You know three things that would be cool?

  • the ability to subscribe to the output of a Flickr API call in a feed aggregator
  • the ability to get the results of Flickr API calls as KML (or GeoRSS)
  • if all those devices that support RSS feeds (like photo frames!) also supported the Flickr API.

You see where I’m going with this don’t you?

You can already specify that you want the output format of a Flickr API call to be REST (POX), XML-RPC, SOAP (shudder, not sure that one still works), JSON, or serialized PHP. We always wanted to support formats like KML, or Atom but we were never quite sure how to represent the results of a call to flickr.photos.getInfo() or flickr.photos.licenses.getInfo() as a KML.

Last week we finally got around to pushing out our 80% solution — an experimental response format for API methods that use the standard photos response format that allows you to request API responses as as one of our many feed formats.

You can now get the output of flickr.photos.search(), or flickr.favorites.getList() as Atom, or GeoRSS, or KML, or whatever.

API Feed Types

The syntax is "&format=feed-{SOME_FEED_IDENTIFER}" where the feed identifiers follow the same convention you use when fetching…feeds.

  • feed-rss_100, API results will be returned as a RSS 1.0 feed
  • feed-rss_200, API results will be returned as a RSS 2.0 feed
  • feed-atom_10, API results will be returned as a Atom 1.0 feed
  • feed-georss, API results will be returned as a RSS 2.0 feed
    with corresponding GeoRSS and W3C Geo elements for geotagged
    photos
  • feed-geoatom, API results will be returned as a Atom 1.0 feed
    with corresponding GeoRSS and W3C Geo elements for geotagged
    photos
  • feed-geordf, API results will be returned as a RSS 1.0 feed
    with corresponding GeoRSS and W3C Geo elements for geotagged
    photos
  • feed-kml, API results will be returned as a KML 2.1 feed
  • feed-kml_nl, API results will be returned as a KML 2.1 network
    link feed

And remember, format is an API arg, and needs to be included in your API signature if you’re making a signed API call.

Namespaces, pagination, bits and bobs

You’ll find the feeds now include the venerable xmlns:flickr=”urn:flickr:” namespace. This is used to declare bits that don’t fit elsewhere like pagination.

Pagination information is passed as a single namespaced (‘urn:flickr:)
element under the feed’s root (or “channel” element if it has one). For
everything but RSS 1.0 based feeds it looks like this:

<flickr:pagination total="480" page="1" pages="96"
per_page="5" />

For RSS 1.0 we do a little RDF dance:

<flickr:flickr>
     <pagination>
             <total>480</total>
             <page>1</page>
                 <pages>32</pages>
             <per_page>15</per_page>
     </pagination>
</flickr:flickr>

Speaking of pagination, to start with we’ve enforced a maximum “per
page” limit of 15. If people have a reasonable use case we may
consider raising the limit but otherwise we need to account for the
extra data/size that feed formats add.

You’ll also find some extras like

<entry>
    ...
    <flickr:views>3</flickr:views>
    <flickr:original type="png" href="http://farm4.static.flickr.com/3074/2783931781_12f84e4079_o.png" width="640" height="480" />
</entry>

Error Handling

If an error occurs, the API will return a 400 HTTP status code.

Flickr error codes and message are returned as X-FlickrErrCode and X-FlickrErrMessage
HTTP headers. For example:

X-FlickrErrCode: 111
X-FlickrErrMessage: Format "feed-lolcat" not found

Caveats and Warnings

  • This is EXPERIMENTAL. It might change, it might go away, but we hope not. We also could potentially make it better based on all your awesome feedback.

  • This is not available for all methods. If you call photos.getInfo and
    ask for a feed response format all you will get is an error.

  • Just like any API call (or feed usage or really anything else) you are required to respect the copyright of the photographer.

  • These are still API calls. All the usual rules about usage apply.
    You are still bound by the Flickr API TOU and any other rules,
    capricious or not, we apply to API usage. Including rate limits. If
    you feed this in to an overly-aggressive aggregator we will make your
    API key cry. (In an entirely non-creepy way)

Putting it together: ego feeds

Turns out ‘kellan’ is a popular baby name these days, so whenever I go ego surfing Flickr I tend to see pictures of two year olds. This changes (for now) when I limit my searching to my friends photos. Using API feeds I can now build an ego feed of photos from my friends, like so:

flickr.photos.search:
   user_id => 51035734193@N01,
   contacts => all,
   text => kellan,
   sort => date-posted-desc,
   api_key => {API_KEY}
   auth_token => {AUTH_TOKEN}
   format => feed-atom_10

api.flickr.com/services/rest/?auth_token=xxxx&user_id=51035734193%40N01&
   contacts=all&format=feed-atom_10&sort=date-posted-desc&text=kellan
   &api_key=xxxx&method=flickr.photos.search&api_sig=xxxx

Putting it together: near home

Or a KML feed of the most interesting, safe, CC licensed photos, within 10 kilometers of a point (say your home), suitable for remixing:

flickr.photos.search:
   license => 1,2,4,5,7,
   sort => interestingness-desc,
   lat => 40.661699,
   lon => -73.98947,
   radius => 10,
   safe_search => 1,
   api_key => {API_KEY}
   format => feed-kml

api.flickr.com/services/rest/?auth_token=xxx&license=1%2C2%2C4%2C5%2C7&
  lat=40.661699&lon=-73.98947&radius=10&safe_search=1
  &format=feed-atom_10&api_key=xxxx&method=flickr.photos.search
  &api_sig=xxxxx

You get the idea.

Standard Photos Response, APIs for a civilized age.

Funny story. I went to write a blog post and when the time came to link to the documentation of our standard “standard photos response” structure, I found we had never documented it!

Okay. Maybe that wasn’t so funny.

But anyway, this is the blog post before that other blog post, so that when I write that other blog post I’ve got something to point to.

And besides you should know this stuff if you’re using the API. It’s good stuff.

Standard Photos Response

The standard photos response is a data structure that we use when we want to return a list of photos. Most prominently the ever popular swiss-army-API flickr.photos.search() uses it, but also methods like flickr.favorites.getList() or flickr.groups.pools.getPhotos().

Beyond a common structure that gets serialized across all our different API response formats, standard photos response methods share a common set of arguments for sorting and paging (after all these are lists of photos), and the special extras argument.

Standard Photo Response, the XML Serialization

You’re basic standard photos response looks like this. It’s just an envelope for delivering a list of photos.

<rsp stat="ok">
  <photos page="1" pages="7" perpage="100" total="608">
    <photo id="2777191844" owner="51035734193@N01" secret="653a19d017" server="3059" farm="4" title="FAIL" ispublic="1" isfriend="0" isfamily="0"/>
    <photo id="2771521705" owner="51035734193@N01" secret="1878507379" server="3178" farm="4" title="In the street" ispublic="1" isfriend="0" isfamily="0"/>
  </photos>
</rsp>

We’ve got the standard Flickr <rsp> root element, a <photos> container describing the full list and the page we’re on, and some <photo> elements that include everything we need to display a photo.

extras: the concept

Another largely undocumented deep structure in the Flickr API is a distinction between getList() and getInfo() methods. We tend to return a pared down list of identifiers, and provide methods for getting more info about individual items. Generally it’s a very useful pattern, and saves us all bandwidth, processing, and data rot.

However sometimes (often?) you’re wanting to display a bunch of photos, and having to roundtrip to call flickr.photos.getInfo() for every single one of them is annoying. (not to mention slow, and likely to get you frowned upon by our ops team)

That’s where extras come in. The idea behind extras is you can selectively enrich the bare bones list I showed you earlier with the metadata you need to display your bunch of photos, without the round trip, and without fetching more then you’ll need.

extras: the details

There are currently 13 different extras available, and we add new ones periodically as new concepts come online, or you make a compelling enough case for them.

As of today they are: license, date_upload, date_taken, owner_name, icon_server, original_format, last_update, geo, tags, machine_tags, o_dims, views, media.

license

Is the photo “All rights reversed”? Licensed under one of the CC license?

<photo id="2777191844" owner="51035734193@N01" secret="653a19d017"
 server="3059" farm="4" title="FAIL" ispublic="1" isfriend="0" isfamily="0" 
 license="3"/>

license=”3” means Attribution-NonCommercial-NoDerivs, you can get our mappings with flickr.photos.licenses.getInfo().

date_upload, date_taken, last_update

When was the photo uploaded to Flickr? When do we think it was taken? When was its metadata last twiddled?

<photo id="2772368826" owner="51035734193@N01" secret="1078392104"
 server="3122" farm="4"       title="Finger on the button" ispublic="1" isfriend="0" isfamily="0"
 license="3"  dateupload="1219006901" datetaken="2008-08-17 12:38:06" 
datetakengranularity="0"     lastupdate="1219117103"/>

Yes the extras param is called date_upload the attribute is dateupload, what can I say, legacy. Notice also that dateupload and lastupdate are epoch seconds, while datetakengranularity is probably best ignored.

owner_name and icon_server

Everything you need to properly credit the photographer, including their name, and the info necessary to display their buddyicon.

<photo id="2772368826" owner="51035734193@N01" secret="1078392104" 
server="3122" farm="4" title="Finger on the button" ispublic="1" isfriend="0" isfamily="0" 
ownername="kellan" iconserver="54" iconfarm="1"/>

geo

If the photo was geotagged include the latitude, longitude, and accuracy of the geotagging.

<photo id="2772368826" owner="51035734193@N01" secret="1078392104" 
server="3122" farm="4" title="Finger on the button" ispublic="1" isfriend="0" isfamily="0" 
latitude="40.714666" longitude="73.957333" accuracy="16"/>

tags and machine_tags

Note these are the “clean” versions of the tags and machine tags, which means spaces, and most punctuation will have been stripped. Safe to display in HTML, and useable as URL fragments.

<photo id="2772368826" owner="51035734193@N01" secret="1078392104" 
server="3122" farm="4" title="Finger on the button" ispublic="1" isfriend="0" isfamily="0" 
tags="nyc streetart williamsburg ph:camera=iphone3g" 
machine_tags="ph:camera=iphone3g"/>

original_format and o_dims

Assuming you’re making API calls as a member who is authorized to download a photo (e.g. the photographer) you can ask for details about the unmodified, full resolution photo that was uploaded. Get the original file format, the secret needed to construct the URL to the photo, and what the original’s dimensions are.

<photo id="2772368826" owner="51035734193@N01" secret="1078392104" 
server="3122" farm="4" title="Finger on the button" ispublic="1" isfriend="0" isfamily="0" 
originalsecret="xxxxxxxx" originalformat="jpg" o_width="1200" 
o_height="1600"/>

views

How many times has this photo been viewed by folks other then the person who uploaded it?

<photo id="2772368826" owner="51035734193@N01" secret="1078392104" 
server="3122" farm="4" title="Finger on the button" ispublic="1" isfriend="0" isfamily="0" 
views="9"/>

media

Is it a photo? Or a video? Has it been processed and is it ready for displaying? (media_status is a lot more useful for videos)

<photo id="2771521705" owner="51035734193@N01" secret="1878507379" 
server="3178" farm="4" title="In the street" ispublic="1" isfriend="0" isfamily="0" 
media="photo" media_status="ready"/>

Wow. What a list. Really, what more could anyone ever want? (that’s rhetorical)

The punch line

That’s standard photos responses, and how to use extras (paging and sorting is left as an exercise to the reader). Mastering the format is the key to building both interesting and performant API applications. use the metadata, love the metadata, and ditch the round trip.

And now for the that next blog post I mentioned ….

Wildcard Machine Tag URLs

Machine tags!

Photo by cackhanded

If you’re not already familiar with machine tags the easiest way to think of them is being like a plain old tag but with a special syntax that allows users to define additional structured data about that tag. In turn the magic space hamsters that run the site have been trained to recognize, index and allow for searches across multiple facets of a given machine tag.

Machine tags have three parts : a namespace which is like a subject or a topic; a predicate which is a like a property of that topic; a value which is … well, a value.

For a more thorough introduction to the subject I’d recommend reading the announcement
we made in the Flickr API discussion group
when machine tags were first added to the site. If you’d like to know even more, after that, there is good collection of links available on del.icio.us.

Which brings us to the part where I tell you that we’ve added the ability to search for machine tagged photos in plain old tag URLs (as well as in tag searches on the Flickr search page) using the facetted query syntax that has always been available in the API. For example :

That’s a trick, really. You’ve always been able to do this since machine tags are just
tags. The New-New means you can be even more granular in what you are looking
for. How about :

The wildcard URL syntax is also available for an individual user’s tags :

Now for the list of caveats and Known-Knowns :

  • At the moment it is still not possible to poke around the hierarchy of a given machine tag : all the predicates for a namespace; all the unique pairs of namespace and predicates; that sort of thing. It is On The List ™ and hopefully we can offer up something for you to play with, even if it’s just in the API to start with, shortly.

  • Values in wildcard URLs should are treated the same way regular tags are in URLs. That is “san francisco” becomes “sanfrancisco” or in machine tag speak : *:*=sanfrancisco.

  • In the examples above, I’ve illustrated namespaces that are used to denote one service or another. It is important to remember that there are no rules about what can or should be a namespace. Like tagging, the hope is that the various communities will arrive at and adapt a consensus according to their needs.

  • Untitled Souvenir #1173678685

    Photo by straup

    In the meantime, kick back and enjoy photos taken by people on their Dopplr trips, photos by people who really really like airplanes or photos by people who are interested in possums
    (not to mention all manner of marsupials) or whatever else comes to mind!