Tag Archives: OpenStreetMap

Open Source Mapping

Hill-shading on OpenCycleMap.org

It was over 18 months ago that I was originally trying to get hill-shading and hill-colouring working on OpenCycleMap (in fact, it wasn’t even called that back then, but that’s a different story). I eventually dropped the hill-shading part of it due to nasty boundary artefacts between source tiles, and due to the fact that the shading, well, didn’t look as nice as I wanted. It was all a bit grey and manky.

Hill Shade Teaser

So instead I launched just the hill-colouring in August 2008, which I was very happy with, and put hill-shading on the back burner. Time passed. Much time.

A few weeks ago, I rolled up my sleeves and got stuck in to figuring out how to do the hillshading properly. With some pointers from Matt, Mike and the OSM Wiki, I played around for a few days until I liked the end result.
Hill Shading results

Here’s a look at Snowdon before hill-shading. The colours do a good job of showing the lie of the land, but it’s a bit flat:
Snowdon Before Shading
Snowdon Before Shading (Detail)
And what Snowdon looks like now. The shading lifts the peaks out from the map, and gives them a more solid-object feel:
Snowdon After Shading
Snowdon After Shading (Detail)
It really helps most in complex mountains, like here in the Alps, where the contours would otherwise become a jumble and it’s hard to tell valleys from ridges. With the shading, it’s easy.
Valleys in the Alps

It’s a hard balancing act, since OpenCycleMap is first and foremost a map for cyclists, and too much hill-shading overpowers and distracts from the rest of the map. But then again, too little and it doesn’t seem worth the effort! I went for a subtle approach, where it’s enough to make the hills stand out but little enough you might not consciously notice. Unfortunately the effect is diminished in forested areas, and by dense contours, since it’s only the background height colouring that is shaded and those things start obscuring stuff.

Also, I was never really happy with the “drab grey” approach to shading – just making the shadows grey and the highlights white using alpha-blending – so I settled in the end for “hardlight” compositing. It’s a bit like the evolution of GUI buttons from Windows 3.11 (“right, top and left edges are white, other two edges are black, grey in the middle”) with those from MacOSX (“ooh, shiny”). Compare OpenCycleMap to Google Terrain and other hill-shaded maps, and I’m quite proud of the results.

If you have a map project that could do with some good-looking terrain info, then I’m available for freelance work.

The View from Above

Over the last few months I’ve been involved in three different aerial imagery projects, all of which were to make imagery available for OpenStreetMap contributors. It’s nice that we have imagery available from the guys at Yahoo!, but on occasion we lay our hands on some better stuff.

First off was Stratford-upon-Avon, here in the UK. As an experiment we hired a small plane, put one of our contributors on board with his SLR, and flew around town. All the photos were then put on line, and even though I’d never been to the place before I could use Tim Water’s online map rectifier and re-purpose it slightly to warp the photos and line them up to the map data. Other people did the same, and then I collected all the separate images and processed them into one map layer. A few days later I was at a “Traditional GIS” conference in Stratford, and there was a great deal of interest from people in the aerial imagery project and OSM in general. I can recommend it as a publicity stunt for other conferences!

Central Stratford

You can see more pictures of the end results on flickr, or read more about it on the OpenStreetMap wiki.

Next up was the Philippines. After massive deadly flooding aid agencies on the ground were using OpenStreetMap to help with the disaster relief. Manning Sambale from the OSM Philippines community received a donation of satellite imagery of part of the affected area, and asked for help processing it and making it available. I made some space available for him to upload it, and then processed it into the right format for OSM editors. With such high-quality imagery available so soon after the disaster, OSM volunteers both in-country and working remotely set about mapping the villages and marking on the locations of bridges and damaged areas. You can get a sense of scale of the damage from the image below – the gravel banks covered fields and villages around the river, and the imagery was a huge help.

Philippines imagery

The third project was in Georgia, USA, where I got hold of some fairly recent (2007) imagery from the Department of Agriculture National Aerial Imagery Program (NAIP). Although Yahoo! has good quality imagery available across the whole of the USA, this public-domain imagery was more up to date and slightly higher quality that what Yahoo! has in rural areas of Georgia. This is by far the biggest set of imagery I’ve had access to – hundreds of gigabytes of the stuff – and only a handful of counties were processed.

Georgia Imagery

I’m sure as time goes on we’ll get more and more sources of imagery to help with OSM, and I look forward to lots of “crowd sourcing” experiments like the stuff from Stratford as much as I like the imagery from the professionals.

If you have access to any sources of imagery and need a hand getting it processed, get in touch!

State of the Map 2007 Videos – in HD!

I wonder whether everyone missed the donations link last time, so I’ll put it first instead! Go on, drop a pound in the collections tin.

When Jon Burgess found out that I was editing the 2008 videos, he dug out his recordings of the first SOTM conference and sent me a disk full of them. This time I knew what I was doing a bit more, and the quality is much improved – in fact, if you have the bandwidth and computer for it, you can also watch them in full HD glory.

Unfortunately Jon didn’t have enough space to record all the talks, but we have 15 available on vimeo. For a full list of talks and links see the OpenStreetMap wiki, or just have a look at my video account and watch them all!

My pick of the bunch are:

It’s great watching these videos – I wasn’t even “into” OSM enough back then to go the conference! And it’s nice to see the things that are wildly different now, and all the things that are still familiar topics.

The Pottery Club

A closeup of a pottery vase in the process of being madeImagine, if you will, a small town with a surprisingly active pottery club. Every week they gather in the local arts centre, and spend long evenings making pottery together. They take lumps of clay and sculpt them into vases, mugs, bowls, teapots and all kinds of things. They share tips and tricks, and help each other out – some people just do their own thing, but there’s a real sense of community. It’s not surprising to find them taking a break together in the local pub, where they spend a lot of time talking about their hobby. The pottery they produce is really high-quality stuff too – a labour purely of love and fascination, not driven by cost/benefit ratios, deadlines or schedules.

Now these people are so interested in their pottery hobby that they happily make far more of it than they need, and so they give away much of the end results – after all, it’s a hobby and they have already got all the teapots they need (and maybe they have a bottomless pit of clay nearby or something that makes this analogy more plausible). And other people appreciate all the free pottery, and wonder what they can do to help. These outsiders come with fairly pure intent – they want everyone in the whole world to benefit from these high quality teapots and vases.

And so the outsiders think about how they can improve this pottery club. They come up with the idea of helping by shipping in partly-made vases and teapots, and letting the club just “finish them off”. After all, it’ll save time and be easier for everyone involved, and gets everyone towards having those next 10,000 vases that much quicker than just waiting for the club to do so in their own time and expand at their own rate. So truckloads of distorted, broken, low-quality, half-finished wet pottery starts arriving at the back door to the club. Some people start taking this pottery and trying to fix it, and a few people in the club think that it’s a great idea. But a lot of people start getting disillusioned. They realise that fixing other people’s mess just isn’t as fun as starting from scratch and making a proper job of it themselves. The banter in the club stops, and it turns into a factory line – no sooner are they finished fixing up one batch of bodged-up pottery than another arrives. More outsiders are scouting around for sources of low quality pottery – after all, if you give it to this Club then they will fix it. But the output quality starts falling as “good enough” pottery is given away, where before they would have bandied together to keep their high standards. People start enjoying the whole thing less, they start drifting away, and the club slowly falls apart. Takings also fall at the pub.

Enough of the story telling. This article is in the “OpenStreetMap” category because I want people to think of this parable when they are considering bulk imports. The strength of OSM is the community. The creation of this dedicated community is a high-quality map. There are ways to help the community, and there is usefulness in using other data sources to assist. But if we continue down the path of treating the community as a mechanism to “fix-up” broken or low-quality data imports, whether that be TIGER, GNIS, NaPTAN or any of the others, then we’ll ruin ourselves in doing so.

State of the Map 2008 videos online (at last!)

I’m sure we’ve all got videos that we mean to edit, or photos we mean to upload, but we never really get round to it. OpenStreetMap has been in a similar position for the last few years regarding videos of its annual conference – the “State of the Map” – which have languished in dark corners. Earlier on in the year I set about tracking down the footage from SOTM08 in Limerick, to see if I could help out. We got hold of the raw footage, and I slowly worked my way through figuring out which clip was which, editing out the inevitable inter-speech faffing, fiddling with the sound and lighting levels and encoding the whole thing. As if that wasn’t enough, uploading them has taken the best part of the last 10 weeks, but it’s all done! Every speech from the main room is now available online, for everyone who was there and wants to reminisce, for those who couldn’t make it to Ireland, and for the 78% of OSMers who have joined up since!

You can find a list of all the talks and links to the videos on the OpenStreetMap wiki: State of the Map 2008

There’s some classic OpenStreetMap history in their, from everything Hiroshi says (sadly with some audio problems in one clip) to Gervase’s now infamous OSM Fieldwork project. Got any favourites yourself? That’s what the comments are for, below.

The observant amongst you will have noticed I haven’t mentioned SOTM07 in Manchester yet, although I’ve been tarting up the wiki page in anticipation of… something… Unfortunately not all of the first conference was actually filmed, but the corollary is suggestive… If you want to help out with my costs for this effort, or simply to show your appreciation, here’s a donations link. If you don’t want to donate, a “thank you” in the comments is a perfect alternative!

From the Archives

Recently I got hold of the original video files from the OpenStreetMap State of the Map 2008 conference. Now I realise that the 2009 conference has been and gone in the meantime, but I think there’s still value in the old videos – whilst a year is a long time in the land of OSM the more things change the more they stay the same.

As for me, here’s a 20 minute video of me talking about the cycle map (it wasn’t called OpenCycleMap back then) as it was around its first birthday. This was the first conference I’d ever spoken at, and aside from making some images before I left home the entire thing was put together during the conference (some things never change…)

Andy Allan: “OSM Cycle Map” at SOTM08 from Andy Allan on Vimeo.

I’ve already encoded all the remaining videos – you can see the full list on the OSM wiki. I’ll be uploading the rest of them over the next few weeks, and probably pulling out a few of my favourites to share with you.

Apart from that, I have two more video editing projects up my sleeve. Now where did I leave all that spare time?

Walking Papers

When I got back from a long weekend yesterday I came across a new project from the legendary Michal Migurski – “Walking Papers“. The basic premise is that when doing OpenStreetMap (especially in partially mapped areas) we all spend a lot of time scribbling on print-outs of maps. For example see one created by Dave that I’ve blogged about before.

So wouldn’t it be great if you could then trace over the printout to enter the data into OSM? This is where Mike’s site comes in. If you print out your map from his site, it comes along with special pictures in the corners that embed some information about orientation and position. So when you scan it in an upload it to the site, it automatically knows where in the world that scan corresponds to and skews your scan to fit properly. And then you can simply trace over your notes with Potlatch to enter your data. More technical details are available from his weblog.

Walking paper of Putney

Even if you don’t want to scan back in, it’s actually a good interface for just printing maps for annotation. The only improvement I’d make to the site would be using OAuth to log into OpenStreetMap (so you don’t give walking-papers your password), but since that’s not implemented just yet on OpenStreetMap.org I can hardly blame Mike! I’ll be very interested to see how many people use the service – you can see what I did when testing it out or simply get started yourself!

Interviews and Awards

Interested in my prognostications on the world’s best cycle map or OpenStreetMap in general? Then check out the recent interview I had with Ed Freyfogle from Nestoria. And while you’re over there, check out Nestoria itself or even better their experimental OpenStreetMap version of Nestoria.

September 2008 was a pretty busy time for me, including speaking at the Society of Cartographer’s Annual conference (slides are online, although of dubious merit without the narration), and running a session on OpenStreetMap at FOSS4G in Cape Town. In amongst all that, I was interviewed by Peter Eich, but thankfully he was happy for me to stick to English!

It was also the month that I received two awards for my work on OpenCycleMap – the first, a Commendation from the British Cartographic Society (coverage over on the CloudMade blog), and additionally the prestigious “Lolcat of awesomeness” from OSM itself – technically I got a part share of the API0.6 award too, but who’s counting?


Last night I went to the first meeting of the unwieldy-named London Geo/Mobile Developers Meetup Group, which was hosted by Google at their London HQ. The three talks are nicely summarised by Gary Gale in his blog post on the event, but I just wanted to include something I always like to see – giant slides showing the cycle map:

Give thanks for the Cycle Map

Nice. But as Mike mentions in the comments on that photo, there’s still a lot of people need awakening to the powers of OpenStreetMap. BikeRadar mentions a campaign to try to persuade Google to add bike routes to their maps (can’t think who “burlyc” might be…) – there’s now 43,000 people signed the petition, when they could already have mapped all the bike paths onto OpenStreetMap instead. Really, as Nick discussed last night in his “Five things you can’t do with online maps” talk, the ideas behind everyone sharing the same, standard, (frequently Google) map are becoming long in the tooth – all the interest and an increasing amount of “cool” stuff is coming from the open-source/crowd-sourced/OpenStreetMap world. We just need to keep spreading the word and getting more people involved.

Replacement Garmin eTrex Bike Clip

After some, umm, over-enthusiastic pinging by a volunteer at a recent OSM Mapping Party, the springy catch on my GPS’s bike clip snapped off. In an attempt to get it fixed I left my brain out of gear and bought a second bike-mount kit from Amazon, but for reasons that still escape me only the handlebar-bit works with the ‘x’ models – in the kit there’s a replacement back for units without the SD card that have the springy-bit molded on but that doesn’t fit most models. So thinking back, I realised the removable clip I wanted had come in the original box, and as much as I fancy a new Legend HCx, I’m not paying hundreds of pounds just because of a two-pence piece of plastic broke!


But, good and surprising news came when I found a forum post that suggested phoning Garmin. Absolutely no hassle, they just sent me one in the post, for free. The cynical would say “just as well, it’s their design flaw” but I just think it’s nice when you stumble across some nice customer service – it makes a change. So if you’re having the same problem (i.e. looking for a replacement 145-00709-00), just give them a call. And a tip of the hat goes to Amazon as well for their returns policy – even refunding the postage. Nice.