Recent diary entries
I don't think I used to map post-boxes. Partly because I'm not that interested in them, partly because I sort of assumed they should have been imported en masse at some point from a Royal Mail open data dump of some sort (naive?).
But when I read SK53's interesting post about the completeness of post-box mapping in Britain, I was really surprised to learn that OSM had less than 50% of the postboxes in Britain. So I've started mapping post boxes when I come across them.
As it turns out, I could have started with the one at the end of my road. It was already there in the map, but it had the wrong reference number, though I only noticed that recently. Even in central London and central Birmingham (two hyper-mapped cities) I've found some postboxes that have sat there unmapped for years.
Anyway, a quick search finds that I've added or fixed 79 post-boxes in the map so far. Mappers, next time you see a post-box, please map it - post boxes are useful things to have on a map...
One of the great things about editing OpenStreetMap is that it leads me to discover new bits of my local area. I've just come back from a lovely walk in North-East London, a walk which I would have never thought of doing if it hadn't been for OSM. And what's more, it led me to discover a really lovely seafood place for lunch!
Here's how I do it:
- When it's a nice day and I fancy a walk, I go and look at ITO's FIXME map, which simply highlights all the objects in the map with "fixme" tags. Most of the time the issues described in the tags are things that can be fixed if someone goes to survey the place (e.g. "check name", "does this footpath really exist"). I pick a few of these fixmes, not too far from home, as waypoints for my walk.
- I usually also go to walking-papers and print myself a simple walking map of the area. I note on this map, the things I need to check.
- Then I go and walk. These days I usually record the GPS trace of my route using my Android phone (I use the "OSMTracker" app) - it's handy but not necessary; just walking around with the piece of paper is fine. For some purposes I prefer scribbling on paper, while sometimes it's quite handy to store notes in the phone.
- When I come back, I upload the GPS trace and use my notes to update the map, fixing things and removing the "fixme" tag wherever I've actually fixed something. The aerial photos that OSM offers (via Bing etc) help to jog your memory as you edit, and often prompt me to add features that I didn't explicitly note down while I was walking.
Really the best thing about this is that while I'm directly fixing things that people want fixing, I'm also discovering bits of my local area that I had no idea about. There was one walk where I discovered an entire park in North-East London that I had never heard of before (and wasn't properly mapped yet, either).
The highlight of today was that my route led me past a fantastic seafood place, and just in time for lunch as well!
On OpenStreetMap, I find the /browse/ pages really useful for getting a quick summary of an "object" in the map. It shows when it was edited, shows all the tags, etc.
However, I have two issues with it:
- The use of space isn't ideal. There's plenty of unused space which I don't think is entirely deliberate (of course whitespace is good sometimes) - and the interesting information often gets pushed down below the fold as a result.
- The browse pages have enough information that they should be generally useful, not just as a diagnostic tool for mappers, but maybe for people who want to share the details of the pub they're going to, or whatever. The main impediment to this is that the initial impact of the page is fairly unfriendly and technical.
I believe the layout can be rearranged in a way which doesn't remove any of the information that mappers need, but which makes the browse pages more accessible and friendly and hopefully generally useful. This would encourage more casual users to see the tags we have, and... fix them :)
So the main objectives are:
- Make the main heading a bit more approachable, making the "name" (where available) a bit more primary than it currently is.
- Make the "Tags" section a little bit more visually primary (more approachable to newcomers than changeset).
- Make the "last edited" info more compact - it doesn't need to be a four-row tabulation, but can be as a sentence "Last edited [date] by [user], (version [v] in changeset [c])". It makes sense to put the "View history" link at the end of this too. Also, it's more approachable to have the last-edited-date converted to something like "2 months ago", and for full info it'd be good to have the full date tooltippy.
- Try not to do anything that prevents experienced mappers from getting a visual overview of the more technical info, such as history, XML link, edit links etc.
Work so far is in my github branch called "browsepage".
I've written a bit more on my own blog including screenshots.
I really think the "Last edited N decades ago by Thor" is much more approachable than the current table of metadata. The other stuff I've done is less dramatic, but I like the way it gives a bit more priority to the tags and makes room for plenty of them in a screenful.
On my blog I made some notes about Diversity and OpenStreetMap, inspired by some of the really interesting talks at SOTM.
This weekend I've been doing some "humanitarian" aerial mapping in response to the floods in North India. My first time trying to map a country I've never visited, where the map might be used for immediate important purposes. I must say it's a bit nerve-wracking, for those exact reasons:
- Firstly I've never been there and I'm not that familiar with the mountainous terrain. Sometimes it's easy to be tracing a river and then you realise you're actually tracing a road after all. When you're not familiar with it, it's much easier to get confused when tracing aerial imagery. We're lucky that the bing aerial coverage for this area seems to be good high-resolution stuff.
- Secondly the mapping might turn out to be important. So, what if my amateurish edits lack something that would have been filled in by another mapper, if only I hadn't filled the map up with simple-minded route-tracing (eg with no idea of which roads are major/minor)? What if I'm tracing a road from an old aerial photo, when locals would know that the road isn't there any more? What if I'm not tracing the things that would be important for humanitarian relief purposes? What if I'm accidentally joining up roads that don't join? etc etc etc. Harry Wood's 2011 discussion of "blooms and weeds" in mapping summarises some ideas about whether importing low-quality data into OSM has a retarding effect on the map's subsequent growth. Maybe rushed naive armchair mapping has a similar effect...
The Humanitarian OpenStreetMap Team ("HOT") has evolved a way of doing things, and I've been a little bit surprised that it's tricky to know how to get involved. By the time a "task" is established in their "tasking manager", it often seems that the basic, low-hanging-fruit stuff like tracing major roads is already done. On the other hand it's good that that stuff gets done quickly because it's presumably important info. This time (with the case of India) I've been able to do some fairly comfortable tracing of roads and rivers, which is good for my own participation. On the other hand it may suggest there's a lot of mapping of the area yet to do, before it becomes useful!
Another iteration of my visualisation of OpenStreetMap edits - here's an animation showing, for each year 2005-2012, the density of edits according to their geographic location:
The upper plot is the raw edit density. The lower one (which I think is more illuminating) is the edit density per unit population, as described in a previous post (with source code).
So what can you see? Well, both of them show the humble London-centred beginnings in 2005, followed by solid growth until the whole world is filled out. I think the lower plot more clearly shows when the "filling out" happens. 2007 is the year OpenStreetMap "goes global" but 2009 is the year it levels out. Before 2009, the edits-per-population are very variable, but from 2009 onwards the picture is much whiter and there's not much annual change in the colouring. This means the distribution of edits much more closely fits the population distribution, though (as noted last time) central Africa and around China are relatively underrepresented.
(This is cross-posted from my blog)
Here's a data-driven way to decide where the next OpenStreetMap recruitment drive should be. Take the geographical spread of edits in 2012, and divide it by the geographical spread of the population, to see where there are most/least edits "per person":
More details on my blog article about it.
OK, if you want to know where in the country has good pubs, how do you do it? Well, here's what I do: download a data extract of all the pubs in the UK/Eire from OpenStreetMap, and use density estimation to look at the distribution of pub attributes such as whether it serves real ale, or food, or has wifi. That's the normal way, right?
In my blog article about pubs in UK & Eire I've posted more plots, as well as the source code and some extra info.