The Race for Timbuktu: In Search of Africa’s City of Gold by Frank T. Kryza | LibraryThing

I mentioned a little over a year ago that I’m now keeping track of what I read (using LibraryThing). I enter the book, the date I finished it, and a rating out of five stars, but I’ve been thinking for a while that perhaps I should do some reviews as well, especially for the good ones.

I recently read The Race for Timbuktu: In Search of Africa’s City of Gold by Frank T. Kryza, about some British expeditions in the early 1800s. Overall definitely interesting, and I was surprised to realized just how recently Europe had zero clue about what lay within most of Africa, Given how shortly after these expeditions most of Africa was colonized.

The main flaws of the book were jumping back and forth between different expeditions in different years, especially in the first half of the book. There are some excellent maps included, but most of them are far too small to actually read much, so I’ve located some of them online:

  1. Africae nova descriptio by Willem Janszoon Blaeu, from page xix
  2. Africa by Sidney Hall, from page xx

The third map from the book I would have also liked to have found; I contacted the British Library for help (mentioned in the book as the source) but they were not able to find it. I’m sure I could get it eventually, but that was the limit of how much work I really wanted to put into this.

Aside from the maps being too small, I would have appreciated having more maps that showed the kingdoms and cultural groups with their boundaries, as it becomes difficult to follow this well given the number of times and places described.

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Some notes on Map Kibera mapping – Mikel Maron

It occurs to me that I’ve hardly mentioned OpenStreetMap on this blog, despite that it’s often an obsession of mine, as people who’ve met me in person would quickly confirm. As the Wikipedia of maps (no other explanation works nearly as well), it is open, easy to contribute to, and I believe, will eventually be the source used for most general mapping applications. Even today it gets quite a bit of use, and growing.

Anyhow, Mikel Maron posts on the Map Kibera blog (Some notes on Map Kibera mapping) about some of the amazing work he organized mapping Kibera, Nairobi, one of the largest slums in the world. It’s interesting how a project that began as a counter to the high-priced Ordinance Survey maps in London has become (among many other things), among the best in maps of the developing world, and and an important resource in humanitarian efforts such as Haiti.

I myself have contributed to the project wherever I am living (or have lived), with lots of contributions around Bellevue, WA, a bit in several places in Toronto, and last week a ton of very detailed and localized mapping in a small section of Florida.

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The Loudness Wars (and leaf blowers)

In an earlier post complaining about excessive noise I briefly mentioned the trends within music. The Loudness Wars: Why Music Sounds Worse : NPR has more interesting details on this include some real stats (sadly using only the top song from each year rather than some sort of average). There’s a Wikipedia article now, Loudness war. Some more anecdotes can be found in an article from the Times Online.

The comfort for me in all this is that people seem to be really realizing that this is a problem and ruining the quality of music, and so maybe we are or soon will hit a peak and then trend back to something more reasonable. Don’t even get me started on people using earbuds whose music can still be heard by others.

Leaf Blowers

Last week I was also reminded of something that’s been bothering me for years, leaf blowers. I’d describe a leaf blower as something that accomplishes the same thing as a rake, but with the added benefit of costing more, taking much longer, requiring more effort, using gas or electricity (cost and pollution), and making a ton of noise. A quick search online for ban “leaf blowers” shows that I am very far from being the only one with this opinion. It appears that a lot of people are working to get them banned, and in some places have succeeded. Let’s hope that spreads.

I did my usual Facebook check and there are tons of anti-leaf-blower groups, with fewer than a couple hundred people in most of them. The Clean Air California website seems to be aiming to ban them statewide or even US-wide. Here (sorta) in Toronto I see an article on a motion to ban them in 2007 which failed for what seems like pathetic reasons including industry lobbying, 6 years after the previous attempt to ban them.

Looking at the leaf blower issue turned up the Noise Pollution Clearinghouse, which seems to be perhaps the American equivalent of the Canadian advocacy site I linked to in my previous post. Last year I attended a lecture at Town Hall Seattle by Gordon Hempton who started the One Square Inch of Silence project, not a bad idea but more significant for it’s symbolism than the one particular place. I don’t have any real conclusion here, I’m just complaining in my usual, not-really-doing-anything-about-the-problem way.

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Comparing NLP APIs for Entity Extraction

Update: a number have people have pointed out some small errors and some additional APIs that I should look at. See my half-hearted followup: Entity Extraction APIs, once again.

As part of a project I’m working on (more on that later), I wanted to be able to take some text (probably in the form of a web page) and get a list of the important entities/keywords/phrases.

It turns out that there are actually quite a few companies that offer a service like this available freely (at least somewhat) through an API, so I set out to try them all out and assess their quality and suitability for my project. Most of these APIs are provided by companies that do various things in the NLP (natural language processing) realm and/or work with large semantic datasets. Many of the APIs provide a variety of information, only some of which is the set of entities that I’m looking for, so they may have good features that are excluded from my narrow comparison.

Using the APIs

To evaluate the APIs I wrote a script to make use of each one (scroll to the bottom to see it in action). They were fairly similar but the code to handle each one is slightly different. In many cases they offered multiple response formats but I opted for XML for each of them which made things simple enough, and I got used to using SimpleXML in PHP. The main difference between them all is simply the XPath expression needed to pick out the entities. For each API I grab the entity, any available synonyms (minus some de-duplication), and the self-reported relevance score for that entity, if available. If not already sorted by that relevance, I sort them.

An additional issue was that although most of the APIs accepted a URL as input, some required the actual content, in either HTML or plain text. When accepting content from a web page, the service needs to be smart about ignoring web navigation, ads, etc. when determining what is important, and they vary in ability to do that. Alchemy (one of the APIs tested here) also has a web page cleaning API which can be accessed on its own. Results from the Yahoo API were of such low quality that I actually ran the input web page through the web page cleaning API before sending it to Yahoo, and it is those results which are evaluated here.

Most of the analysis here is based off a sample of eight web pages including Wikipedia articles, news articles, and other pages with a lot of text content from a variety of subjects. I have not yet done any analysis of how the quality of the response for each API is affected by the length of the input document.

The APIs

The APIs I tested were, roughly in order of increasing quality,

Comment on this post to let me know if I’m missing any.

API terms

Most APIs today have limits on both how much they can be called, and what you can use them for. Here they are ranked roughly by “most usable terms and limits” to least:

Currently no API limit; essentially no requirements
30,000 calls per day (although more may be available); commercial use is definitely okay
50,000 calls per day, 4 calls per second; one must display their logo as-is; if you are syndicating the data it needs to preserve their GUIDs; see details
2,000 calls per day, 1 call per second; essentially no requirements
5,000 calls per IP per day; non-commercial use only
1,000 “transactions” per day; note that one call is 1-4 transactions depending on the input type and whether you want all or a subset of the output; commercial use is definitely okay

Please note the standard I-am-not-a-lawyer and that this is just a summary. Please read the terms of service yourself.


Although my project is English-only for now, ideally there would be support for other languages. All the samples I used were in English so that is what is being used to evaluate the quality, but here is the full list of what languages each API claims to handle:

English, French, Spanish
A white paper on their website claims that their technology can support multiple languages, but most likely only English is currently supported
English, French, German, Italian, Portuguese, Russian, Spanish, Swedish, however some important features are only available for English

I have not done any research into similar APIs which are not available for English at all, but if you find one, please let me know and I’ll make a note of it here.

The response from OpenAmplify and AlchemyAPI will also include the language of the input document. For AlchemyAPI this includes 97 languages, not just the ones that the API can handle. If you’re just looking for good language identification, there are other resources for that, some open source. My ancient Language Identification page still has some useful links there.

Number of Entities and Relevance Scores

For the purposes of my project, I see the APIs which return more entities from the document to be more useful, all else being equal. BeliefNetworks allows you to specify the number of entities returned (supposedly up to 75 but it actually returns 76), and as such always returns that number, which is almost always more than any other API. Yahoo returns up to 20 entities (which isn’t documented), which is often the least of any API. Here I list the APIs sorted by number of entities returned from most to least:

  1. BeliefNetworks
  2. AlchemyAPI
  3. OpenAmplify
  4. OpenCalais
  5. Yahoo
  6. Evri

There are a couple of important caveats here, however. This is based off of a very small sample, so other than BeliefNetworks returning the most, the list could be off. Beyond that, OpenCalais has a fairly small limit on text length (100,000 characters, presumably including the HTML tags) and if the input is too long, it returns no entities at all, just an error message. The ranking above excludes those examples. OpenAmplify has a limit of 2.5K, however they just truncate the document instead of failing (although this counts as an additional “transaction”). Oddly, Evri returned an error of “rejected by content filter” for this news article and returned no entities. Evri’s ranking in the list above is unchanged with or without the inclusion of that example.

Relevance Scores

All of the APIs, with the exception of Yahoo’s, include some metric with each entity rating its relevance to the input document. This is important as every user of any of these APIs would most likely want to establish a minimum relevance threshold for actually making use of the entities. The number of entities comparison above is based on no threshold at all; obviously changing the threshold would affect the comparison. AlchemyAPI and OpenCalais use scores from zero-to-one, however Evri, OpenAmplify, and BeliefNetworks have their own scale. I haven’t yet done any work to normalize all these scores and I think that most likely the best practice would be to independently determine your own threshold on a per-api basis depending on your own needs.

Semantic Links

By semantic links I simply mean that the entities returned have some sort of links or references to additional information about those entities. Although not necessarily required for my project, this may be very useful. Two of the APIs, Evri and AlchemyAPI include this information when they successfully map a found entity to an entity in their own database. Evri provides a reference to the entity in Evri’s own system, whereas AlchemyAPI links to a variety of other sources: the website for the entity, Freebase, MusicBrainz, and others.

In addition to or instead of these semantic links, Evri, AlchemyAPI, and OpenCalais have their own systems of classification and label entities with things like “Person” and “Religion”. See Evri’s most popular ‘facets’, AlchemyAPI Entity Types, and OpenCalais: Metadata Element Simple Output Value for specifics of each. OpenAmplify is even more basic but provides broad categories such as “Locations” and “Proper Nouns”, and entities may be listed in more than one of these broad categories. Yahoo and BeliefNetworks provide no additional context.

Additional Information

Some of these APIs provide a wealth of information that I disregard entirely but could be useful to others. For example Amplify returns a lot of information about the sentiment being expressed about each entity, information about the person who authored the document (e.g. gender, education), the style of the document (e.g. slang usage), and actions expressed within the document. OpenCalais also extracts events and facts from a document, as well as other details per entity such as the ticker symbol for entities which are public companies. AlchemyAPI can extract quotations from the document. Note that this is a summary and not a complete list of all the data that these APIs return.

Synonyms vs. Duplicates

The better APIs here, at least as far as I’ll be using them, succeed at recognizing that “Smith” referred to throughout an article is the same as “John Smith” mentioned in the first sentence. I want duplicates minimized, and for each entity to have as many valid names/synonyms as possible. The APIs differ here significantly.

Evri is definitely the best, followed by AlchemyAPI. Unfortunately AlchemyAPI sometimes misdisambiguates (ooh, no results on Google or Bing for that word yet) which results in incorrect synonyms, however that isn’t a huge problem for me. An example is the article I referred to earlier where AlchemyAPI confuses a Canadian military unit for the British monarch it was named after. Yahoo and OpenCalais fall into the middle. OpenAmplify and BeliefNetworks have a fair number of unmerged duplicate entities. For my purposes, I don’t care if the synonyms come from the input document or an external database, which is what Evri and AlchemyAPI probably use.

Taking a look at each API


This was the only API that I was aware of until recently, and I’ve blogged about it before. The input format is plain text, so since I’m using URLs as input, I have to first extract the text, strip the HTML, and send that. As I mentioned above, the quality was so poor when using web pages as input that the text must first be scrubbed of web page navigation, etc., and I used AlchemyAPI to do that. Even then, the quality was still poor and the API returned things that I would describe more as long phrases than as entities. Given that, not to mention the maximum of 20 entities, and the non-commercial restriction, I don’t see myself making use of this API.


This API also accepted content rather than a URL. The content format must be specified in the API call. I simply retrieved the URL, and passed all of its content (with HTML) on to OpenCalais. They suggest making sure to remove web page navigation, but without me doing this, that didn’t present a problem. What was a problem was the short maximum document length. To actually use OpenCalais you should make sure to truncate documents before making the request, which is work that I haven’t yet implemented myself. Even when results were returned, the overall quality was mediocre.

The default output format is RDF, which is very verbose and includes a lot more information than I needed. I opted for the Text/Simple format which is actually XML.

For free API users sometimes the response comes back as “server busy” and I experienced this myself sometimes while trying it out.


This API has a simple output, and is somewhat unusual in its functionality. Unlike all the other APIs, where the entities are extracted from the input document, with BeliefNetworks it seems they find entities which are related to the document but not necessarily actually in it. This produces some interesting results that are sometimes good but overall less related than I’d expect, and in one of my examples, completely unrelated and bizarre. Given that, and the frequency of duplicate entities, as mentioned, I would describe the overall quality as mediocre, although usually better than OpenCalais.


The most notable feature of OpenAmplify is all the additional information they provide, as described above.

They take input either as a URL or the content itself, and “charge” an additional transaction if you call them using a URL. I used URL input but also tried submitting the HTML, submitting the text (HTML stripped), and submitting the text after putting through the AlchemyAPI web page cleaning, and in all cases the results were about the same or worse.

OpenAmplify notes that they may not be able to follow all URL redirects (although I didn’t test this with any of the APIs), but this issue can be avoided by following the redirects yourself before making the request. As mentioned earlier, they only look at the first 2.5K of input. They also accept RSS/Atom as input, which is a nice feature.

Although I’ve set up my script to remove duplicates it currently misses removing some duplicate entities from OpenAmplify as the entity may be listed several times in the response but with different relevance scores.

One problem I found was that the entities returned usually consisted of a single token (one word) which just made them less useful. Overall, the quality was okay, generally better than BeliefNetworks.


Other than the occasional misdisambiguation, AlchemyAPI is quite good.


Evri’s API is also quite good, with the biggest flaw being that it doesn’t return very many entities.

Overall Quality Summary

Overall, Evri and AlchemyAPI were definitely the best and most suited for my purposes. The quality of Evri’s was the best across the small sample, although not in all instances, and it didn’t return as many entities as AlchemyAPI. Interestingly these two APIs are also the two which include semantic links and have the least restrictions and high API limits.

OpenAmplify and BeliefNetworks are the runners up. OpenCalais fared poorly in my evaluation, but I suspect it would do better when looking at all the rest that their API. Yahoo’s API unfortunately just wasn’t good enough to use when any of the other APIs are available.

I’m convinced that trying to build a similar service myself is not worth it at all. One thing that I haven’t tried yet is combining these APIs together in some way, although that could potentially improve the results quite a bit.

You can see the script in action (until I take it down) at[any URL].

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On the US Gov’t “Going Google”

On the US Gov’t “Going Google” – very true. Google has had great success, and thus they are a problem.

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Yahoo! Will Kill MyBlogLog Next Month

Yahoo! Will Kill MyBlogLog Next Month – of all the services Yahoo’s been killing, this one is just sad. MyBlogLog was pretty innovative and just as useful today as it always has been, despite years of nothing new. At the moment, you can still see it on the side of this blog’s homepage. Via Scott Rafer

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Well, I’ve updated the ‘ol resume. And my actual resume spells it properly. I can’t reference the old one as apparently I set it to not be indexed by search engines.

Basically I updated all the information, restructured things a bit, reworded a bit, and removed the section on “soft skills” (e.g. communication and team skills, etc.). Having that section always seemed odd. Of course the resume itself seems odd… distilling myself into a list of concrete things certainly makes me look far more boring than I’d like to think I actually am. I feel like just a five-minute conversation would be far more useful than the resume, but then again nobody has the time, which is the whole point.

I made some slight tweaks to the styles and added some light hResume (already used hCard). It’s pretty basic, as I prefer to have it work with or without CSS, without javascript, and print black-and-white onto one regular sheet of paper.

Anyhow I’ve been massively overwhelmed by support since the layoff. Fortunately little things like this don’t bug me much 🙂

As an aside, it looks like I’m in good company, Don Dodge was laid off as well.

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On being laid off from Microsoft

So I got laid off from Microsoft on Wednesday. I wasn’t really bothered about the job, as I wasn’t happy with it already and had been looking to find something else for quite a while. The unfortunate part is that it affects my immigration status and so I can’t stay that long right now in the US, where many of my friends are. But I had been planning on returning to Toronto within a year or so anyhow.

The Details

Since a lot of people have asked me, here are all the details I’ve got. There have been three rounds of layoffs at Microsoft this year (this is supposedly the last). I knew people who had been laid off in both prior rounds. In those cases they were all relatively new employees, but that is partly the bias of me being friends with people my own age. In those rounds we also lost several members of my team.

My manager found out on Monday, and I was told on Wednesday. I’d figured it out earlier on Wednesday due to the odd nature of the meeting invitation. Anyhow that was Wednesday and by end of today I will be fully out having taken my stuff from my office and returned all work property. Various things like my work e-mail and building access ended on Thursday or today. As to why I was chosen, I presume it is a combination of having low seniority (been at Microsoft a bit over a year) and my record (my annual review wasn’t stellar, long story), although I didn’t ask and I’m not really interested.

What Now?

I’ve got a couple of weeks that I can stay around Seattle to look for employment, otherwise I’ll head home to Toronto. Even then, if I find a job in Seattle it will be much easier to return that it was for me to get here to begin with.

That’s pretty much it. I’m not really sure that I want a job at all right now (whether in the Seattle area, Toronto area, or otherwise), but for the time being I’m considering all options. If you’re really that eager to hire me or have something else in mind, let me know.

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Canadian Asbestos Exports

So I already knew that despite asbestos being banned in Canada (among many other places), we still export it to countries with poor health and safety regulations, which I find pretty horific. I was watching a CBC news segment on a flight a couple ago of days about it which brought it back to mind. For one thing, they pointed out that only around 500 people are employed by this in Canada. This seems like a pretty clear-cut case of us doing the wrong thing.

So I figured there must be a petition on this, so I’d just go online and find it and sign it. Not so simple it turns out. There are, and have been, lots of petitions. As recently as the last few weeks, there is a new petition, but it seems like only companies can sign it; I’m not entirely sure what the point of that is. Here is a petition received by the government in 1997 along with what I would describe as an extremely pathetic and predictable government reply. The reply basically says that we tell other countries to use it safely, and it’s not our fault if they don’t listen and die as a result.

Finally I find the Ban Asbestos Canada website, which includes a broken link to an actual petition, and I managed to figure out what the real link is supposed to be. So go this petition page and from there you can enter in a few details to send a letter to all of the federal party leaders. If I were them I would also add on the relevant cabinet ministers (Health, Trade, Natural Resources, Public Safety, maybe a few others), and the MP and MPP for the riding that includes the remaining asbestos mine.

Oh, and I checked Facebook too. There are at least seven petitiony groups on this (of course), but the largest has only 230 members.

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MapDotNet : Blog : Google voice recognition software used in street data collection process?

Last week Google replaced thier base maps in the US, no longer using data from TeleAtlas. The new data isn’t from OpenStreetMap either. I think we are finally starting to figure out where it all came from: MapDotNet : Blog : Google voice recognition software used in street data collection process?

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