Category Archives: OpenStreetMap

Meteor Mapping


Metero Crater is the well-named meteor crater in Arizona created by a “nickel-iron meteorite about 50 meters (54 yards) across, which impacted the plain at a speed of several kilometers per second. The speed of the impact has been a subject of some debate. Modelling initially suggested that the meteorite struck at a speed of up to 20 kilometers per second (45,000 mph), but more recent research suggests the impact was substantially slower, at 12.8 kilometers per second (28,600 mph). It is believed that about half of the impactor’s 300,000 tonnes (330,000 short tons) bulk was vaporized during its descent, before it hit the ground.[7]”

I drove the 3 hours there, then 3 hours back to visit it from Phoenix, Arizona yesterday and took some pics:

And of course I mapped it. There are a bunch of footpaths, a subway fast food restaurant, lookout points and so on. Of course someone had already mapped the crater rim and the car park. Check out the map here.

License Working Group podcast

As many of you will have seen the OSM project is in the midst of shifting license due to problems with Creative Commons applicability to data. You can read why here, here and here. There has been a lot of discussion on the mailing lists about this and with any license debate in an open project a lot of FUD. Today Matt Amos and Mike Collinson, members of the LWG together with Peter Batty, Richard Fairhurst and myself produced a podcast which covers many of the issues. To discuss more please feel free to comment on this post or join the legal mailing list where this has been discussed approximately 9 billion times over the last 2 years.

Map Editors Comparison

Matt has an interesting post comparing Map Editors:

I’ve been playing with the changeset data for OpenStreetMap and looking to see what patterns I can find in the usage of various editors since changesets were introduced in the API 0.6 migration. We can start off just looking at the major editors by distinct users, i.e: everyone’s favourite popularity contest.


Mikel parachuted in to Kibera last month – a holiday destination known as the “second largest urban slum in Africa” – to make sure it’s all mapped. The results have been impressive:


It includes a website, map data of course and social media including twitter and interviews:

The press release is worth a read:

Kibera remains a blank spot on the Kenyan map, though it holds as many as one million inhabitants according to UN-HABITAT. Its limited health and water resources, traffic patterns, and housing layouts remain largely invisible to the outside world and to residents themselves. Though many organizations have collected data on Kibera, the information is not yet shared as a resource for all to use. Map Kibera will fill in this gap by producing free, open-source digital map data using the techniques of OpenStreetMap, a user-edited map of the world. The resulting information will be freely available to residents, NGOs, private companies, and others interested in working with and for Kibera.

Introducing a new OSM editor… Potlatch 2

OpenStreetMap users will know all about Potlatch, the online editor that appears when you click the ‘Edit’ tab on the site. Well, there’s a whole new version coming soon!

Potlatch 2 is a complete rewrite still with the same principle in mind: an editor which hits the right balance between speed, ease-of-use, and flexibility. It’s under very active development at the moment and I’ll include a link at the end of this post where you can have a look.

But there are four big new features – and one behind-the-scenes change – to tell you about first.

New feature – friendly tagging system

Potlatch 2 has a friendly, intuitive tagging system. The mapper can use graphical menus, dedicated fields, and icons to get the tagging just right – without the need to remember tag names and values.

For example, you can choose highway types from a set of icons, then add a speed limit by selecting the appropriate restriction sign.

Potlatch 2 tag editor

All this is fully customisable using a straightforward presets file. Using this, you can create your own favourite tag combinations.

New feature – WYSIWYG rendering

Potlatch 2 has an all-new rendering engine far in advance of the current one.

With road names, patterned fills, rotated icons, and much more, the editing experience can be like working live on the familiar Mapnik rendering, the cyclemap, Osmarender, or anything you like -making it much more approachable for the beginner.

The Halcyon renderer used in Potlatch 2

Just like the tagging, the rendering is easy to customise. It uses a special form of CSS, called MapCSS, which lets you create wonderful-looking maps with just a few lines of text. The tagging and rendering together make Potlatch 2 ideal for ‘vertical’ mapping applications, such as a cycle-specific editor or a building/addressing editor. Stylesheets aren’t just about making the map look pretty: you can create stylesheets to help your mapping, such as one that highlights roads without names.

The rendering engine (Halcyon) is available as a compact (<100k) standalone component which you can embed in webpages, so your custom maps can be used outside Potlatch 2.

New feature – Beginners’ Guide

You couldn’t write instructions for Potlatch without writing instructions for OSM. The new Potlatch user needs to know about tagging, surveying, and copyright – but they’re certainly not Potlatch-specific.

So Potlatch 2 will have an accompanying ‘OSM Guide’, explaining the basics with friendly, illustrated text. It will be concise, focused and clear.

New feature – vector background layer

Mappers are working more and more with imports. But the approach until now has been to import data directly into the map – and many people have pointed out the problems this can lead to.

Potlatch 2 will support vector background layers. You can load OSM-formatted data from servers or files, and work on bringing it into the map the way you want, at your own pace.

Because this integrates fully with MapCSS stylesheets, you can choose to temporarily hide background data, or show (say) only footpaths… whatever you like.

Fully rewritten in ActionScript 3

Potlatch 2 is written in ActionScript 3, a Java-like language with an open source compiler and full docs available online. The Potlatch 2 source comes with instructions on getting started and is, of course, permissively licensed under the WTFPL.

Potlatch 2 thus far has been written by Dave Stubbs and Richard Fairhurst (me). But we would love to see more people hacking on the source. There’s a potlatch-dev mailing list especially for this.

Playing with Potlatch

So where are we up to right now, and how long do you have to wait?

The tagging system, rendering engine, geometry editing, and server communication are all up and running – the core of the editor, and the real hard work.

Some other features, like Yahoo and tiled backgrounds, are finished but not currently exposed through the editor: they’ll be along shortly. Others, such as GPS track support, the Beginners’ Guide and the vector background layer are not coded yet but are intended for the initial release.

Potlatch 1 has some three years of development behind it, of course, and much of this feature set has not yet been ported to Potlatch 2. There’ll be countless little UI tweaks (no keyboard shortcuts yet, for example!); and as you’d expect for an in-development version, performance can sometimes be sluggish and there’s a lot of optimisations we’d like to do.

But with work progressing so fast, this seemed a great time to talk about it. Both the tagging system and the renderer are enormously flexible and we’d like to see people hacking on them as soon as possible.

So how about some links? You can find a read-only running version at:

or play with the renderer alone at:

Should you want to try a particular area, just put the lat and lon in the URL like this:

and the source is at:

and you can read MapCSS documentation at:

Have a play, let us know what you think, and grab the source!