When OpenStreetMap put a slippy map on its front page on its front page in 2005 it used a Mercator map. This made excellent sense at the time: true north was at the top everywhere, angles were good (spherical Mercator less so than geoidal Mercator) and the raster tiles at then in use could be scrolled without spending computational power on changing their shape. Other maps at the time made the same decision for the same reasons.

Twenty years on desktop and even mobile processors can render vector tiles with consummate ease, keeping the labels in the right shape while they do so. The need to keep tiles the same shape has evaporated and many maps can be spun to put whichever direction the user wants at the top. But the disadvantages of Mercator remain: at small scales Canada and Greenland are exaggerated in size compared to Africa. At large scales this is more subtle, each zoom level maps Helsinki at a linear scale twice as large as Bogota with four times the area and shifting a zoom level doesn’t mix well with map styles that use the level to show differing amounts of detail. There is more than a further zoom level of difference between Helsinki and Longyearbyen. The widest used scheme for tile URLs leaves a hole 1000km across around each pole; this was tolerated because the is no land in the Arctic hole and, as any Australian will tell you, the southern hemisphere doesn’t count.

… See full entry

Like much of the web, OSM has been struggling with bots downloading rendered maps, in our case declining to use our planet dumps to get what they want.

I therefore make a suggestion: give suspected scrapers a poisoned version of the map, for instance it could have scrambled POIs, or perhaps roads named after villains. We can then point out the source of the resulting contamination as it goes public.

After an unfortunate setback in 2020 the 14th in-person State of the Map conference will be held in Africa for the first time, underlining OSM’s status as a truly global map. Long may our commitment to going round the world to experience what we are mapping continue.

I’ve never heard complaints from the many people who attended Foss4g and the HOT summit in Dar es Salaam and I am confident that Nairobi can be a similar success.

One of OpenStreetMap’s greatest strengths is our worldwide platform backed by a worldwide community. As such we need to give our full support to our mappers around the world, including the ones in countries whose cultural and legal norms you may dislike and wish to work against. Supporting these mappers isn’t an endorsement of those norms; rather it is a commitment to worldwide mapping.

Any suggestion of ostracising countries would be a stand against inclusion of mappers, depriving them of the opportunity to talk about their specific issues both with each other and with the rest of the world.

During lockdown it’s been difficult for me to go long distances to map; instead I’ve tried to fill in every house in the SW14 postal district, consisting of East Sheen and Mortlake, where only about half of them had been mapped before; I realised I could fit ground surveys into the allowed daily exercise. I have also tidied Mortlake station, which had been a complete mess, and completely redrawn the landuse polygons northeast of the level crossing, which had previously put retail in the wrong place.

After several years of work buildings are still patchy in OSM in London. The gaps are all too obvious when you use apps such as Maps.me, and of course mapping houses leads to better mapped roads.

After a time when I solidly filled in all of the houses in an area near where I live, I decided to change my mapping approach. I am now filling in buildings and addresses facing A roads and bus routes in half a London borough, the bit of Richmond upon Thames that is south of the river and east of the rest of the borough.

I see these buildings as important because:

1. People travelling along these roads get a full set of houses that they can follow.
2. As these are the longest roads they are the most valuable to search using the whole address because the street name is not precise enough.
3. This includes a large proportion of businesses that are worth mapping.
4. The gaps between mapped houses are broken up, this makes them more attractive for the long tail of occasional mappers to fill in the gaps; some of them could be our next enthusiasts.

As I write there is still a bit of work left.

One thing that [ have ducked out of tackling so far is the landuse polygons, which are a mess. They often intersect buildings, the commercial landuse in Barnes bears little resemblance to the actual town centre and polygons that were drawn arbitrarily on the map in Richmond acquired concocted names. The only quick thing I could have done would be to delete them completely, which I do not want to do unilaterally.

What could be done is to redraw the polygons adding the extents of the relevant properties to create one or more residential/commercial/other polygon for every street block, as the logical conclusion of landuse polygons that exclude roads. Extents are now available for import though it may very well be better to add them from aerial imagery.

Every year (most of them anyway) OSM holds its State of the Map conference where our international community get together to show off the art of mapping and to talk to each other so we can make the best map of the world.

This year we are meeting in Brussels from 23 to 25 September. Having attended State of the Map in the past I found both the talks and the opportunity to meet other mappers positive, and I am looking forwards to meeting many of you there.

As has happened several times recently, there is again no image featured on the wiki’s front page on Monday. Maybe we should be promoting the image of the week. Maybe the proposals page isn’t friendly enough to passing submitters and needs to be made more welcoming. Maybe the community are no longer interested in featuring pictures and it should be scaled back or dropped.

Is there something about the project you’d like to show the world? A photograph of an OSM activity perhaps, or some interesting mapping? Maybe there’s an alternative rendering of our data you’d like to show off, or an application that uses our database in an interesting way.

We show an image a week on our wiki’s front page with the story behind it. You can suggest your favourite picture at Featured image proposals. If people come up with interesting ideas they’ll be shown off to the world.

You can also add a description for each featured image in your language. You can follow the editing links beneath this week’s picture on the wiki’s front page and community blogs or you can use the “Add a description in your language” link in the archive of feature images.

Have fun!

Boundaries for London boroughs have recently been imported from OS Opendata Boundaryline. On balance I think this is a good thing because the boundaries are much more detailed than the straight lines that much of London had, being separate ways they are more robust than doubling up roads as boundaries and London has got a good enough community to take them on; that last is where I come in.

I have surveyed the boundary between the London boroughs of Richmond upon Thames and Wandsworth. Much of the boundary follows the Beverley Brook;this stream is roughly mapped at the moment. There are two places where the boundary goes in another direction. There is a chunk of Barnes Common that is west of the stream but in Richmond. The crossing of Lower Richmond Road is clearly visible in terms of signs and Wandsworth street name signs on the west sides of Hallam Road and Beauchamp Terrace confirm that the boundary is west of the roads. The other exception is Richmond Park, where the whole park was incorporated in Richmond in 1994.making mapping the boundary easy.

Please note that the Google map below shows Brooklands Museum in the wrong place! It is actually to the right, on the other side of the river, just beneath London Bus Museum’s logo, which is in the right place.

North-west Surrey was mapped early by a mapper who has not accepted the ODBL and contributor terms. As such, tagging doesn’t always reflect the latest ideas and it will go away in a few months’ time.

A few of us have been tackling this backlog. I’ve removed most of the non-compliant mapping from Weybridge so that mappers can work and most roads have been remapped. But there’s more work to do.

Team Surrey is a project to remap Surrey to the latest standards and to plug the ODBL deficit maintain the good mapping in the county.

Although the majority of the most active contributors to OSM have agreed to license their contributions under the ODbL, some people have not yet done so. The reasons for not having done so are many and varied: some mappers haven’t been contacted yet, some are opposed to the thought of their contributions being made available under ODbL terms, which I respect even though I disagree with it; some people still hope the Foundation will change their mind ignoring the damage to the community from supporters of the licence change being betrayed, some have fallen out with the project and want to go out with a bang, some lack confidence because they don’t quite understand what the licence change means and some are naturally cautious about signing any agreement.

Unfortunately a few mappers are seeking to gain an advantage by threatening not to sign up for as long as they can and twisting people’s arms in the process. Bullying is not of course unheard of in online communities; the licence change has give some bullies an opportunity.

My message to the bullies is that although we would like your contributions along with everyone else’s they are not so critical we need to grovel to your self-importance; they can and will be replaced. To anyone who’s been bullied about licences or anything else, we’re here to help.

The side street that a previous mapper saw south of Gervase Street in Peckham, London (presumably on a photograph) isn’t a street at all. Visiting the area it turns out to be a private parking space.
And another thing — speak up more. I’ve never had any feedback about the quality of my contributions whether following on from mapping parties or elsewhere. I just don’t believe I’ve got everything right. Even when what I’ve done is good as far as it goes I’m sure I’ve missed useful tags. More feedback gives me and others a chance to improve contributions.

After the Latimer Road mapping party I’ve been adding the blocks of flats in the White City estate. I haven’t managed to set up plugins yet in JOSM so I’ve been tracing over the Yahoo pictures in Potlatch. I’ve found I can trace over the outline at roof level in the photographs (although this is not as simple with pitched roofs) and then move it to where you can see the bottom of the building, remembering that you have to select the way itself intead of the highlight roun it. The ‘use thin lines at all levels’ option is useful here but the outlines still don’t seem as crisp as I’d like. Practice makes perfect I suppose.