1. Visualising transparency, for AllTrials

    You may know Dr Ben Goldacre from his ‘Bad Science’ and ‘Bad Pharma’ campaigns, which fight misinformation around medicine. Ben has just launched his latest project, the AllTrials Transparency Index — and mySociety helped with the website side of things.

    The AllTrials campaign focuses around the fact that a shockingly large proportion of clinical trials do not have their results publicly published.

    Not only does this devalue the time, goodwill and even potential risk put in by participants, but there are also issues around bias. Those trials published tend to be the ones which show positive results: if that doesn’t sound like such a terrible situation to you, try playing this game from the Economist magazine, which graphically depicts the problems with skewed coverage. At worst, such selective publication can be dangerous, or lead to poor choices from bodies making medical purchasing decisions.

    Transparency and data visualisation are two areas where mySociety has a long history, and so it came to be that we fashioned the deceptively simple AllTrials Transparency Index site, on which anyone can browse the transparency index of the world’s major drug companies, and dive in deeper to the data to see how it was compiled. The source data is free for others to download too, so anyone can integrate it into other projects.

    All Trials transparency ranking

    AllTrials are also tracking whether companies register new trials:

    AllTrials graph, showing registered trials

     

    That’s the part that anyone can understand — and now, notes for the more technically-inclined who may be wondering how we took the data on each drugs company and presented it in a way that can be quickly and easily taken in.

    This is an ongoing campaign with a commitment to future audits, so we wanted to make it easy for the AllTrials team to update the site and republish the source data each time they do.

    It’s a static Jekyll site. We wrote a custom plug-in to parse a CSV and produce a page for each company within that CSV, as well as creating some summary data that feeds into the graphs on the front page.

    This data is then pulled from the CSV, and D3 is employed to build the graphs and insert them into the generated pages.

    The end result is a site that looks good and which can automatically update whenever the underlying data changes. We hope we’ll have played a small part in helping to ensure that it does — and for the better.

    All Trials company profile


    Header image: Komu News (CC by/2.0)

  2. Re-imagining the Joint Strategic Needs Assessment for the digital age

    Public health teams, policy-makers, councillors and NGOs often need facts about a specific area. If they’re looking for data on things like the number of smokers, the demand for hospital beds, or the birth rate, they turn to their regional Health and Wellbeing Board.

    These local authority committees are required to produce a document known as a JSNA (Joint Strategic Needs Assessment) every few years. It’s a snapshot of the demographics and healthcare needs of the local population, and is used by a variety of stakeholders including policy makers and strategy groups.

    Like most local authority committees, the London Borough of Hackney and the City of London Health and Wellbeing Board have previously produced their JSNA as a simple read-only PDF document. But, in the digital age, they knew that there was more they could do to make this document accessible, useful, and engaging.

    That’s when they called us in — not to build the final digital version of the JSNA, but to help them understand the possibilities and ensure that they were heading down the right path.

    We’ve written up the whole process in a case study, so, if you’d like to know more, read on.

    Image: Nick (cc)

  3. 12 exciting projects mySociety was hired to deliver last year

    Image by Craig Sunter

    Not many people realise that we fund a proportion of our charitable work by carrying our commercial development and consultancy work for a wide range of clients.

    Last year, we scoped, developed and delivered a real variety of digital tools and projects. Some of the projects were surprising. Some of them made us gnash our teeth, a bit, as we grappled with new problems. But all of them (and call us geeks if you like) got us very excited.

    Here are just twelve of our personal high points from last year. If you have a project that you think we might be able to help you with in 2015, we’d love to hear from you!

    1. We Changed the Way in Which Parliament Does Digital

    Palace of Westminster by Greg DunlapThis time last year, a small team from mySociety was poring over analytics, interview content and assorted evidence from Parliament projects dating back last 2-3 years, to help us put together a simple set of recommendations to conclude our review.

    11 months later, Parliament have announced their first Head of Digital, fulfilling one of our key recommendations.

    2. We helped the MAS and the FCA protect financial consumers

    Bubble Car by Allen WatkinTwo of our projects helped people financially.

    We built the Money Advice Service’s (MAS) first responsive web application, the Car Cost Calculator.

    This tool takes one simple thing you know (the car you wish to buy) and tells you roughly how much it’ll cost to run that car against any others you might be interested in. It has been one of MAS’ most successful online tools in terms of traffic and conversion.

    We also built the Financial Conduct Authority’s Scam Smart tool, aiming to prevent financial scams.

    This tool helps users considering a financial investment to check a potential investment. Users enter information about the type of investment, how they heard about it and the details of the company offering it to them and get back tailored guidance and suggested next steps to help them ensure the investment is bona fide.

    3. We Gave Power to the People of Panama (soon)

    Alaveteli homepageWorking with the The National Authority for Transparency & Access to Information (ANTAI) and the Foreign & Commonwealth Office (FCO), we set up our first government-backed instance of our Freedom of Information platform, Alaveteli, in Panama.

    This project will ensure that Panama’s FOI legislation is promoted and used, but it will also shine a light on ANTAI, who are responsible for ensuring ministries and organisations publish their information, and handling case appeals.

    4. We Mapped All the Public Services in Wales

    Bws Ysgol - Image by Aqwis via Wikimedia, CCAfter we extended the Mapumental API to produce data output suitable for GIS (geographical information systems), the Welsh Government were able to map public services in Wales for their Index of Multiple Deprivation calculations.

    Over the course of the year they have calculated travel times for over seventy thousand points of interest.

    5. We Launched a New Organisation in Four Weeks

    Simply SecureSimply Secure approached us in dire need of a brand, an identity and a website to accompany the launch of their new organisation to help the world build user-friendly security tools and technologies.

    Cue four weeks of very intense work for mySociety’s designer, supported by members of the commercial team. And we did it.

    6. We Printed Stuff BIG (and found people jobs)

    Public transport travel times to Birmingham meet-up, from Mapumental by mySocietymySociety developer Dave Arter figured out how to generate A1 sized maps from Mapumental for every job centre in the UK – all 716 of them.

    Xerox will be using these with the DWP to help job seekers find work that is within reach by public transport. As a byproduct, Mapumental now handles high-fidelity print based outputs: get in touch if that is of interest.

    7. We Opened Up Planning Applications

    open-planning-shotWith Hampshire County Council we had the opportunity to build a new application to help assist members of the public and business better understand what was happening around them. For us, it was also the first application in which we worked closely with a provider of a linked data store, in this case Swirrl.

    When Open Planning goes live, it will look to help improve social engagement and the economy of Hampshire through better understanding and transparency of planning data.

    8. We Proved (Again) That FixMyStreet Isn’t All About Potholes

    CollideoscopeAfter a spate of cyclists’ deaths in London last year, we felt that the moment was right to build something that would support cycle safety in the UK.

    We launched Collideoscope on October the 7th with our first sponsor—Barts Charity, with the aim of generating data both on incidents involving cycles, and near misses.

    9. We Helped Launch a Film

    A map of old Norse place namesWe built a tool for the British Museum, to go alongside the general release of Vikings Live. The Norse Names project brought a sense of context and personalisation to a dataset gathered by the University of Nottingham.

    10. We Made Data More Exciting

    To the Trains by Nic McPheeIn 2013, we built an interface to help people explore the data in the National Rail Passenger Survey (NRPS) data explorer  for Passenger Focus.

    This year, they asked us to build something similar for bus users. We’re entering the final week of development now, and the finished product should be launched in March.

    The main aim of this site? To take data that could be considered pretty dry, and make it a lot more engaging.

    11. We Fixed Yet More Potholes

    Fixed, by Tup WandersThis year Warwickshire, East Sussex, Hart & Harrogate joined the list of councils using FixMyStreet as their main street fault reporting platform.

    That means that residents of those places can now make their reports direct from their council’s website, or via FixMyStreet, and either way they’ll have all the benefits of FixMyStreet’s smooth report-making interface.

    12. We Showed Parliament the Way

    Parliament Square by Duncan HarrisAnd so, we end where we began. While Parliament were busy interviewing candidates for their new ‘Head of Digital’ position, we were commissioned to demonstrate what Hansard might look like were a platform like SayIt used instead of the largely print-based publishing mechanisms used today.

    The result was shared internally. While SayIt may not be the end solution for Parliament, it’s great to have had some input into what that solution might be.

    And in 2015…?

    Got a project that you’d like us to be involved in?

    Get in touch and tell us about it.

    Image credits:

    Eggs: Craig Sunter; Parliament: Greg Dunlap; Bubble car: Allen Watkin; To the Trains: Nic McPhee; Potholes: Tup Wanders; Parliament Duncan Harris. All Creative Commons.

     

  4. Accessibility of Welsh schools by public transport – visualised

    A commission from the Welsh Government has resulted in new functionality for Mapumental, which now has the capability to display multiple points and to produce RAW data compatible with GIS applications. Here’s how it happened.

    Bws Ysgol - Image by Aqwis via Wikimedia, CCHow accessible is your nearest school, post office, or GP’s surgery? In Wales, that’s not always a simple question: the country’s mountainous landscapes, rural populations, and sometimes infrequent bus services can mean that those without cars are rather cut off from public service provision.

    But of course, like any other authority, the Welsh Government has an obligation to quantify just how accessible their services are.

    For many years, they have done so using a number of different methods. Some of these involve literally millions of point to point calculations – so, naturally, when Bill Oates, Head of Geography & Technology, Knowledge Services at the Welsh Government, approached Mapumental, he was keen to discover whether we could simplify things.

    We were keen to try it, too – plotting multiple points would add a whole new slew of possibilities to Mapumental. Previously, Mapumental has been all about travel from a single point, and this functionality would bring new applications across all kinds of industries and users.

    There’s only one way to find out

    The sensible way forward was to pick a single service and see what we could do. One of the government’s open data sets showed positioning of all the secondary schools in the country, and would give us a very good indication of how manageable the task would be across all other provisions.

    So we set ourselves this aim: to display the shortest transit time to get to any secondary school in Wales, from any point in that country.

    This project was not like the map we made for the Fire Protection Association last year, with its postcode input and interactive sliders. It bore more relation to our static maps, but with the additional dimension that the single map would have multiple points plotted on it. Each point would display its own associated journey times, and where travel to one school was quicker than to another, it would have to override the data of the school that was further away.

    And here’s the (very pretty) result

    Welsh secondary schools travel times mapTransit times by public transport to secondary schools in Wales, with an arrival time of 9:00am.

    Time bands are in 15-minute increments, with red areas being those where schools are accessible within a 15-minute journey (the centres of the red dots therefore also represent the positions of the schools).

    Purple areas are those where journey time is between 1.75 and 2 hours, and the colours in between run in the order you see bottom right of the map. White areas (much of which are mountainous and sparsely-populated) are outside the two-hour transit time.

    But there’s more – data for GIS

    Plotting all the schools on a single map required quite a bit of modification to Mapumental, but there was another important part of the project that also had to be worked on, if the output was to meet all the needs of the Welsh Government.

    They needed to be able to export the raw transit time data to their own GIS tools – the tools that they use to feed into official statistics. This allows the transit time data to be  combined with other datasets, such as population density, for in-depth analysis.

    We added a feature which allows Mapumental to produce what is known as a ‘raster grid’ output – basically, an enormous matrix that gives every pixel on the map a travel time value. To do this, we used the open source GRASS format.

    What’s next?

    Bill Oates is keen to see where this project can go:

    “I’m really excited at the prospect of combining the power of Mapumental with our open data, and fully understanding how accessible Welsh public services are by public transport.”

     

    To him, the benefits are clear:

    “Mapumental’s approach is significantly quicker than our current methods, so this work will help save us time as well as providing a more engaging output.

     

    “We hope that future work with mySociety will give us a sustainable approach to calculating the accessibility of local shops, hospitals, post offices and other services on an ongoing basis to help ensure that we’re meeting the needs of our citizens.”

     

    We’re looking to build on our success, and offer this service to others – initially on request but via our API as soon as we can. We’ll keep you posted as to our progress.
    You can see multiple-point mapping in action, on our Mapumental Property project – now the tool allows house-hunters to take more than one person’s commute into consideration when choosing where to live.

    Who might use Mapumental?

    Now that Mapumental can plot transit times from multiple points, and provide RAW data for GIS applications, we have great potential for use by anyone interested in travel and accessibility. That could be in central and local government strategy, town planning, architectural consultancy, transport provision, large enterprises looking to save on parking, or start-ups in the green transport space…to name but a few.

    Could Mapumental help you with your mapping needs? If so, please do drop us a line at hello@mysociety.org.

    Photo of Welsh school bus (bws ysgol) by Aqwis (CC)

  5. Event report: Choosing the right data presentation method for your organisation

    In this series of talks, we’re exploring how organisations can present data meaningfully and accessibly – and how to maximise the benefits, both for themselves and for their stakeholders.

    If you are interested in attending a mySociety Data For Breakfast briefing, drop us a line and we’ll add you to our mailing list.

    Mike Thompson from mySociety

    It was great to see so many people at our latest Data For Breakfast event, where our Senior Consultant Mike Thompson explored how you can match a data presentation method to your organisation’s aims.

    Mike’s uploaded his presentation, along with others in the series, on our Slideshare page, but I’m also going to summarise it here, as Mike said a lot more than you’ll glean from the slides alone – and there was some really useful conversation from our attendees.

    Click to read more

  6. Fire, fire! Mapumental and fire engine journey times

    Image by William Murphy Mapumental can turn vast datasets into visual tools that everyone understands. Faced with highly complex, yet crucial data from the Fire Protection Association, we had a chance to really put our technology through its paces.

    Just how quickly could fire engines reach a given postcode in case of a fire? It’s a question that’s pivotal to decisions made by both the emergency services and the insurance industry.

    But previously, it has been a challenge to present the data simply, because it involves so many variables.

    Every region has its own factors, each of which will impact on fire engine response time. The number of vehicles at each station, the hours during which the station is manned, and the response policy of each individual fire authority will all play a part – and that’s before you even consider how geography might affect things.

    Dr. Jim Glockling is Technical Director at the Fire Protection Association and Head of the Risk Insight, Strategy and Control Authority (RISCAuthority), an organisation for the advancement of risk management within the fire and security sectors. Jim approached mySociety with this question: how could we map this crucial, yet complicated data in a way that could be understood by RISCAuthority members at a glance?

    It was clearly a job for Mapumental. Our transit-time mapping software was originally built to visualise public transport journey times, but its beauty is that ‘layers’ of data can be swapped out, allowing it to be used for all kinds of purposes.

    Read more about mySociety’s data visualisation services here.

    Assessing a property or postcode

    How quickly could 4 fire engines get to AL10 0XR in 10 minutes and 10 seconds?

    How quickly could 4 fire engines get to AL10 0XR in 10 minutes and 10 seconds? (Click to enlarge)

    And here’s the result of our pilot project. The maps on the right answer the following questions (click each image to see it at full size):

    How quickly could 4 fire engines get to AL10 0XR ?

    FPA: arrival times one engine

    FPA: arrival times one engine (click to enlarge)

    How does that change if the severity of the fire just requires one fire engine?

     A user inputs a postcode, and can assess exactly how quickly a fire could be tackled in that area. The different levels of severity are measured by how many response vehicles are required, and changes in this number are immediately reflected on the map.

    Assessing the general area

    FPA  - what it looks like when you have no postcode

    Which areas can four fire engines get to within 9 minutes 30 seconds at midday on a Saturday?

    It’s also possible to assess the region’s overall response capability, without inputting a postcode. The user sets severity levels (number of fire engines, or High Volume Pumping or Aerial Appliance (ladder) is needed), the time and day of the week.

    FPA - aerial response arrival within 15 minutes

    Where can an aerial appliance get to within 15 minutes at 2am on a weekday?

    The FPA tool immediately highlights the areas that are accessible within the chosen parameters, drawing on the underlying data of journey times and information such as vehicle numbers and hours of operation for each individual fire station in the region.

    Simplicity itself

    With RISCAuthority, we tested the concept using data from one fire authority –  Hertfordshire. mySociety’s task was to create a usable, elegant web interface that was as simple as possible to use, while still giving insurers the key data they needed.

    The project called on everything we knew about clean design, usability and data structures. A key part of what makes Mapumental’s data visualisation so intuitive are its sliders: this enables the user to quickly explore variables on a map.

    A tool with purpose

    Dr Glockling explains: “Whilst not necessarily used as a component of insurance pricing, this information helps insurers administer risk control and fire protection advice to their customers in the context of what the Fire and Rescue Services will be able to achieve on their behalf.”

    The response time is just one factor that insurance surveyors will take into account when they are assessing a building. “Where response and arrival times are not coherent with protecting the viability of the business in the event of fire, additional forms of in-built protection and control might be recommended, such as the installation of sprinkler systems.”

    “In the longer term it is hoped such information will impact beneficially on the annual cost of fire in the UK.”

    Results

    The pilot tool was well received by the FPA community, and the plan is now to work with RISCAuthority to roll it out to more fire authorities shortly, and then nationwide.

    Dr Glockling explains the pilot study helped them to understand two factors:

    • Would they get buy-in from both insurers and Fire and Rescue services on the viability and usefulness of the project?

    • Was it possible to present such a massive amount of data in a format that was readily palatable to the intended audience?

    He says, “Mapumental’s team displayed an immediate understanding of our requirement. Delivery was to time and the result has perfectly satisfied the de-risking ambition. The working relationships were very good throughout and we intend now to extend the pilot to full UK rollout.”

    During this phase, we will be inputting still more detail to the data, including information on the types of fire engine available to each region, and the plotting of fire stations on the map.

    The tool will be a valuable resource for the FPA and the insurance industry, and we really look forward to the roll-out later this year.

    Mapumental specialises in visualising complex geographic data sets on intuitive, easy to use map tools. If you have a data visualisation project that will benefit from Mapumental, just get in touch. Or read more about mySociety’s data visualisation services here.

    Photo by William Murphy (CC)

  7. Mapumental’s Secret Sauce: A Map Overlay Rendering Technology You Might Find Interesting

    I am Duncan Parkes,  a developer for mySociety, a non-profit full of web geeks. One of the things we try to do well here is to take complicated data and turn it into really usable tools – tools which are attractive to people who aren’t web (or data) geeks.

    For some considerable time I’ve been working on Mapumental – a project that is about turning public transport timetable data into pretty, interactive maps featuring isochrones, shapes that show people where they can live if they want to have a commute of a particular time. You can play with the new version we just launched here. That particular map shows the commuting options to where the Queen lives. Slide the slider for full effect.

    There are a couple of hard problems that need solving if you want to build a service with an interactive journey times overlay like this. You need to be able to calculate a *huge* number of journeys extremely quickly, and you need to be able to make custom map layers so that it all looks nice. But what I think might be most interesting for you is the way in which the contours get rendered on top of the maps.

    It all started about three years ago, when the first version of the app – co-developed with the geniuses at Stamen – used Flash/Flex to draw contours on the maps, and to let people play with them. You can still play with a couple of versions of that technology from way back in 2007, that is, unless you’re using an iPad or iPhone, which of course don’t do Flash.

    Colour Cycling

    What was going on inside this Flash app was as follows. We needed to show the user any one of hundreds of different combinations of journey times (5 minutes, 12 minutes, 56 minutes, etc) depending on where they set the slider. Sending each one from the server as a tiled map overlay would be dead slow. Even Google – who have chosen to send new tiles each time – end up with a service which is surprisingly slow (try choosing a different time on this map).

    With some help from Stamen, we decided that the way of making it possible to show many different contours very quickly was send the client just one set of tiles, where each tile contained all the data for a variety of journey times. What does that mean? Simple: each colour in the tile represented a different number of minutes travelling on the map. So a batch of pixels that are colour X, all show places that are 15 minutes from the centre of the map.

    So, in this old Flash system, when you slide the slider along, the Flash app makes some of the coloured pixels opaque, and the others transparent. It was, in short, a form of colour cycling, familiar to lovers of 8 and 16 bit computer games.

    However, from about 2010 onwards, the march of iOS spelt the end of Flash. And that meant that we couldn’t launch a shiny new site based on this technology, as lovely as it was. We had to work out some approach that would use modern web standards instead.

    The Death of Flash Makes Life Difficult – for a while

    How do we replicate the experience of dragging a slider and seeing the map change like in the original Mapumental demo, but without Flash? One of the things that made the original Mapumental nice to use was how smooth the image changes were when you dragged the slider. Speed really matters to create that sort of organic effect that makes the demo so mesmerising.

    So as we started to tackle the question “How do we make this work in a post-Flash world?”. And the first thought was “Let’s do away with those map tiles, filled with all that journey time data!”. After all – why send any tiles to a modern browser, if it can just render nice shapes on the fly?

    So we had a go. Several goes. At first we tried rendering SVG circles around each public transport stop – but that was too slow, particularly when zoomed out. Then we tried rendering circles in Canvas, and whilst that was OK in sparsely populated places it sucked in the cities, where people would actually want to use it.

    Eventually, we decided that as wonderful and powerful as modern web rendering techniques are, if you exclude WebGL (on the grounds that so few people have it still), all the current techniques result in pages that just hammer your browser, whilst producing an experience which isn’t up to our previous Flash-based standards. To see this in action, see the wonderful Mapnificent site, developed by the super talented Stefan Wehrmeyer. He’s a great guy and a friend of mySociety, but the Javascript circle rendering just grinds, and that’s with far, far fewer data points than we have in our system. (Sorry for potentially crashing your browser there. This is in the interest of Science.)

    Back to Colour Cycling – Using Web Standards

    So, we thought, why not look again at colour cycling the pixels within pre-rendered map tiles? After all, there are some examples out there, like this waterfall, all in Javascript.

    So, I had a bit of a look at the waterfall. It seems to work by holding in memory a structure which has all the pixels which change and all the colours they should change to and when. This works beautifully for the waterfall picture, but only a limited number of the pixels in that image actually change colour, and the image is quite small. For a full screen web browser with a big map in, this didn’t seem promising, although I’d love to see someone try.

    Then I thought: browsers have always been very good at displaying images quickly – that’s sort of vital. Perhaps we could get our tile generating server to output PNG images where, as before, the colours represent travel times, but using a palette. Then by putting this in a canvas layer in the JavaScript mapping framework Leaflet, and by changing the palette of the images on the canvas as the slider is dragged, we could get our animation.

    Unfortunately, there is no way to change the palette of an image that you’ve put on the canvas. In fact, there’s no way to change the palette of an HTML img element: all you can do is assign it a new src attribute.

    But this gets back to the original problem – we don’t want to download new mapping for every different position on the time slider. We definitely can’t afford to have the client downloading a new image source for every tile whenever the slider is moved, so we had to find a way to make that src at the client end and get that into the src attribute.

    The Breakthrough – Data URIs and Base64 encoding

    So we started trying data URIs. For those of you not familiar, these allow you to put a whole object into your HTML or CSS, encoded in Base64. They’re commonly used to prevent pages having to make extra downloads for things like tiny icons.

    So I thought, “Here’s a way we can set an image src in JavaScript to something we’ve calculated, rather than something we’ve downloaded.” And this turned out to be the key insight that allows for the relatively smooth, attractive overlays you see in Mapumental today.

    My new plan was that the client, having downloaded each palette-based image, would make a Base64 encoded version of it, which it could then use to build a version with the right palette and assign this as a data URI of the tile.

    However Base64 encoding all these images in the JavaScript seemed like unnecessary processing to do there, so the final evolution of this technique was to do the Base64 encoding at the tile server end, and while we’re at it, not to bother sending over the parts of the image that we always replace at the client end.

    So in summary, what we built does this:

    1. The server calculates the journey times and renders them to palette-based tiles.
    2. It sends these to the client, encoded in Base64, and with the initial bits up to the palette and transparency chunks removed.
    3. At the client end, we have a pre-prepared array of 255 ‘starts’ of PNGs that we combine with the later parts of the ’tiles’ from the tile server to make data URIs.
    4. When you drag the slider it combines the appropriate ‘start’ of a PNG with the bulk of the tile that has been downloaded from the server, and assigns that to the src attribute of the tile.

    And that’s how the nice overlays on Mapumental work. But as so often in coding, the really interesting devil is in the detail – read on if you’re interested.

    Diving into Base64 and the PNG file format – The Gnarly Bits

    So – why are there 255 of these ‘starts’ of these PNGs, and what do I mean by a ‘start’ anyway?

    PNG files are divided up into an 8 byte signature (the same for every PNG file) and a number of chunks, where each chunk consists of 4 bytes to tell you its length, 4 bytes of its name, some data, and 4 bytes of cyclic redundancy check. In this case, what I call a ‘start’ of a PNG is the 8 byte signature, the 25 byte of the IHDR chunk, and the PLTE (palette) and tRNS (transparency) chunks. The PLTE chunk has 12 bytes of overhead and 3 bytes per colour, and the tRNS chunk has 12 bytes of overhead and 1 byte per colour.

    Base64 encoding is a way of representing binary data in text so that it can be used in places where you would normally expect text – like URIs. Without going into too much detail, it turns groups of 3 bytes of binary gumpf into 4 bytes of normal ASCII text without control characters in it, which can then be put into a URI.

    Why do we have 255 colours, rather than the maximum 256 which are available in a palette? Because we need the break between the end of the tRNS chunk and the start of the IDAT chunk in the PNG file to align with a break between groups of three bytes in the Base64 encoded image. We need the length of these starts to be a multiple of 3 bytes in the original PNG format, which translates into a multiple of 4 bytes in the Base64 encoded version, so we can cut and shut the images without corruption.

    Which just goes to show that even though web GIS technologies may feel like they are approaching a zenith of high level abstraction, there’s still some really gnarly work to be done to get the best out of current browsers.

  8. Mapumental Property Launches

    If you’ve been following mySociety for a while, you’ll know that we have been interested in making maps that show commuting times for several years.

    However, we’ve never made public a simple, free, useful version of our slidy-swooshy Mapumental journey times technology. Until today.

    Today we pull the wraps off Mapumental Property , a house-hunting service covering England, Scotland and Wales, designed to help you work out where you might live if you want a public transport commute of a particular maximum duration. Have a go, and we guarantee you’ll find it an oddly compelling experience.

    We think it’s a genuinely useful tool – especially since unlike some of the other players in this space, we’ve got all the different kinds of public transport, right across the whole of Great Britain. We hope that some of you will find it helpful when deciding where to live.

    However, this launch doesn’t mean mySociety is bent on taking over the property websites sector. Mapumental Property isn’t a challenger to the likes of Rightmove, it’s a calling card – an advertisement for our skills – which we hope will help mySociety to attract people and organisations who want beautiful, useful web tools built for them.

    In particular we’d like people interested in Mapumental to note that:

    • We like to build attractive, usable web tools for clients of all kinds.
    • We know how to use complex data to make simple, lovely things.
    • We can do some mapping technology that others haven’t worked out yet.

    If any of that is of interest, please get in touch, or read about our software development and consulting services.

    I’d like to thank quite a few people for helping with this launch. Duncan Parkes was the lead developer, Matthew Somerville ably assisted. Jedidiah Broadbent did the design. The idea originally came from the late Chris Lightfoot, and me, Tom Steinberg. Francis Irving built the first version, and Stamen came up with the awesome idea of using sliders in the first place (and built some early tech). Kristina Glushkova worked on business development, and Zoopla’s API provides the property data. I’m also grateful to Ed Parsons of Google for very kindly giving us a hat tip when they built some technology that was inspired by Mapumental.  Thanks to everyone – this has been a long time coming.

    We’ll follow up soon with a post about the technology – and in particular how we got away from using Flash. It has been an interesting journey.