SK53 has commented on the following diary entries

Post When Comment
Land Use versus Residential Private Property 10 months ago

@CloCkWeRX I still don't get exactly why it needs to be in OSM: are you wanting to free cadastral data from commercial constraints,? 'cos it doesn't sound like it when you mention commercial datasets. The type of application you describe sounds mainly of interest to organisations which can afford non-free data.

Most of the applications that use landuse which I am interested in: contesting major planning changes, pollution in watersheds, environmental (habitats/biotopes etc) value of particular areas, and so on - are things which single individuals, small non-commercial groups, and charities are likely to want to do.

@AdamMartin it's nothing to do with database weight (if I understand what you mean by this), although lots of buildings from cadastral data in France are regarded by many mappers as 'bloat' (largely because houses w/o addresses arent very interesting), it's to do with the pain of processing lots of polygons. The nature of OSM is that one does have polygons in polygons.

Land Use versus Residential Private Property 10 months ago

Broadly speaking don't use landuse for zoning areas.

Use the landuse tags for what is on the ground (which of course ought to correspond with local zoning). Many local administrations will do zoning on a long-term timescale of perhaps several decades. It is no use to anyone to mark areas earmarked for new sections as residential if they are still farmland.

Secondly, dealing with many hundreds of landuse polygons will make landuse data from OSM more or less unusable. Because there is no enforcement that given types of polygons must not overlap, a lot of post-processing is needed on OSM data already. Increasing the number of objects (by perhaps a hundred- to a thousand-fold if you map individual house plots as residential and individual shops as retail. Additionally complex algorithms are then needed to define landuse beyond property boundaries.

I've yet to see a convincing use-case for mapping property boundary details in OSM: enough people have done it to show it's possible, but I'm not aware of anyone with a need to get this data from OSM. Incidentally the vast bulk of use-cases for landuse (including cartographic products) require reasonably generalised polygons.

Think bout boundary of INDIA 11 months ago

I suspect that you think that the boundary of India should include all of the pre-partition States of Jammu and Kashmir. However it is policy for OpenStreetMap to map what is on the ground. This effectively means that we try and map the Line of Control accurately, rather than areas claimed, but not controlled by India or Pakistan (and indeed China).

The reasons for this are straightforward, OSM is used in countries on both sides of border disputes and therefore it is impossible to adhere to both views of where notional borders might be. Furthermore OSM, unlike, say the maps of the Survey of India, does not serve political purposes. OSM is not a platform for fantasy maps, whether those created by individuals or mandated by legislation by governments.

I realise this may create problems for people in India where it may be an offence to represent the boundaries of India other than according to the states wishes, rather than any accordance with reality. For that purpose I would suggest using an external source for the boundary of India: moving the boundary away from the LoC will be treated as vandalism.

If on the other hand the boundary needs minor tweaks (which I'm sure it does) and you can map them based on personal observation or sources which are open, usable in OSM, and readily available for others to check that such mapping is accurate then do go ahead.

I have also answered this on [OSM Help](

Adding addresses: NG9 11 months ago

This is a great piece of work: and an extremely thoughtful insight into the complexities of address mapping.

tagging a green roof? 11 months ago

Green roofs often have a wide range of different plants depending on a whole host of factors. Relatively few will be seeded with grass.

More often they will have relatively drought tolerant plants, certainly local ones have lots of sedums, and a range of Carophyllaceae (Dianthus, Petrorhagia and others).

For this reason I have used the green_roof=yes tag, see

OSM datasize in PostGIS 11 months ago

In my experience its often faster to use osmosis to write a pgsql dump & just use copy to do the import (--pgd option in osmosis).

I think you'll find most of the storage overhead is in the geometry columns

Mapping Croydon 11 months ago

The Food Hygiene ratings have a large number of shops, pubs, schools, hospitals (and a few oddities) with OGL address data including postcodes. Their lists exactly fulfil your idea of hunting down POIs from a list. The data for Croydon LB is here: (warning XML). You can read this with Excel or I could send you a CSV extract with the key info. The lat/lon are actually the postcode centroid.

Addresses from an old survey 11 months ago

OGL is fine. Even Ordnance Survey OGL is OK, but tedious from an attribution viewpoint. CodePoint Open is not OK, but we can substitute the Office for National Statistics postcode data set which is to all intents and purposes identical.

In addition Food Hygiene, Land Registry and other available data sets (such as Planning Applications) contain a huge amount of useful address information. See my blog Maps Matter for far more about this.

We have huge amounts of OS data under their extended OGL, and as OGL is in effect a more liberal licence there is no problem with OGL.

Would there be any use for a builder=* tag? 12 months ago

In the UK the phenomenon of a housing estate being known locally after the company which built/developed the land is pretty common. The area of Silverdale in Nottingham was (and may still be) known as the Wimpey Estate (a national firm of house builders); and the Hofton Estate (a local firm of builders) is to the west of Wollaton Road.

The development off Cranbrook Drive in Maidenhead is still called the Sterling Homes estate some 30 years after it was built.

The up-market house developer Berkeley Homes always puts a distinctive marker of properties which it develops including the year of completion.

Recent controversy about 1880s housing in Liverpool (the Welsh Streets) reminds me that there are many examples of 19th century builders leaving their mark in street names, such as these streets which spell out the names of the builders, Owen and Williams.

In other words there is plenty of evidence here that such information tends to stick around in the public memory.

Another reason, particularly for national builders, is that individual building firms often have a particular house-style of building. Wimpey houses of the 1970s are very recognisable, but I'm sure to this is true of other builders. I know architectural historians can often date old buildings with surprising accuracy because certain features reflect specific time-bound trends. I am sure that there are plenty of clues as to the builder in a similar way.

Activity on rail 12 months ago

Be careful UPRN's belong to someone.

Lycian Way - Turkey 12 months ago

Many parts of the Lycian Way are mapped between Fethiye and Antalya, see (might be a bit slow to load) for an idea of what is there.

Relations aren't readily downloadable as a GPS track/trail although it is possible.

If you are using a Garmin device there are many ready made files containing walking routes, see Extremecarver offers downloads specifically made for walkers and mountain bikers at Openmtbmap, with useful optional contours as well.

Activity 1 12 months ago

I think that you don't need to do this.

You are probably not aware of relations which are used to add things like the European Road network. See this page on the wiki.

Here is an example of a short one E 24.

Many of these relations are very unwieldy (take a long time to save when edited), so the int_ref technique might still be preferable, or the relations could be broken up which was done with the US Interstate system

Updating housing site no 5... about 1 year ago

You have an issues with projections: you can't just grab OSM data and hope it to look like OSGB data.

I'd do this with Quantum GIS, set up a project using the OSGB projection (EPSG: 27700) with conversion on the fly checked. You can load some OS OpenData into this (for instance the 250k raster or the Meridian 2 vector data are both very suitable).

Then download your required OSM data (this should now be re-projected automatically into OSGB). Do whatever styling is required.

Now create a composer which enables you to set the bounds of the area (I presume you mean 6 1km squares) & export this as SVG.

You could also download your OSM data as Shapefiles and use ogr2ogr to do the conversion, but this is what QGIS is doing and it hides some of the gory detail.

The SVG files can be huge: I've not bothered with them myself, preferring PDFs.

Airport Runway Names over 2 years ago

Hmm, how do we know these exist except from Google Maps. If that is how we found out about them then we're deriving this data from Google. Doesn't seem like a good idea for me. Let alone using Google Maps to name the runway.

GNIS does have names for islands in this part of the Gulf. According to Birding UAE both islands are private without access. One of them may still be a breeding site for the Socotra Cormorant.

Rae Lakes loop over 2 years ago

fee=yes/no is a more or less universal issue in UK (particularly railway (train) stations which are more or less 100% fee. Toilets are increasingly only open with restricted hours, once the decision has been taken to close them the opening time is determined by staff hours. See Gail Knight's blog for a comprehensive introduction to the issues.

There is a good tradition about obsessing about mapping toilets and sanitation facilities on OpenStreetMap and often for very good reasons: How to map open defecation areas".

Naming passes seems difficult... over 2 years ago

The usual way to mark a pass is with a node tagged mountain_pass=yes with a name=* and ele=*. This could be a node on the way marking the trail or a single standalone node.

For part of a longer trail which both have names follow the suggestion of FK270673 (a relation for the longer trail and its name, the way for naming a section of the trail).

There is a single use of a tag for trailhead with a value of start. I'm sure marking trailheads has been discussed on one of the mailing lists in the past. Feel free to use the existing tag or invent one of your own. The bulk of mapping footpaths in OSM is European-based where most footpaths form a dense interconnected network, so the notion of a trailhead is less significant. Signposts (finger posts), waymarkers and information boards are much more likely to be mapped.

Check out Lonvia's Hiking Map to see which trails have been mapped worldwide: at large scales this shows a lot of hiking related detail.

RGB Colours almost 3 years ago

In the mapnik stylesheet onSVN

There might be slightly more accessible sources (e.g., the html for the map key).

Anyone working on Tokyo? almost 3 years ago

There is a Japanese local chapter with a website here:

There have been several recent events, some associated with conferences or HackforJapan events. Several members of the Japanese OSM community are active on twitter (Ikiya, Mapconcierge) and Ikiya has a blog.

Phone number entry needed + Edit today almost 3 years ago

Nice edits, welcome to OSM.

To add a 'phone number, select the advanced edit option (at the bottom of the left hand panel) and the tags associated with the object are displayed. Just add a new tag with key "phone" and put the phone number in the value field. As OSM allows free-format tagging, the editor only supports a limited subset of the more popular values.

To realign the power-line you'll have to a ground survey: this need be nothing more than notes on a sheet of paper as to where the powerline now runs. Finding where it crosses streets is the easiest way. I imagine it would be useful to use other landmarks (prominent buildings etc) to help fix the alignment. Walking papers provide a facility for printing out OSM maps or Bing aerial imagery which are designed for this kind of data recording.

Aerial imagery is always out-of-date to some extent: one of the powerful things about OSM is that one can create maps of one's own neighbourhood which are much more up-to-date than other sources. This might be the re-routed powerline, the new housing division, a major road realignment, or just a nice new pub or restaurant.

Place du jardin d'Alençay almost 3 years ago

À lire: Compte-rendu du Conseil Municipal du lundi 5 octobre 2009, à 20h. (Saint Pierre des Corps).


"Dénomination de voies

* Il est proposé les dénominations suivantes, pour le réseau de voiries situé dans le lotissement de la Cerisaie :

1. rue de la Cerisaie : entre l’avenue Lénine et la place du Jardin-d’Alençay 2. rue Eugène-Bizeau, poète libertaire tourangeau, à l’ouest de la rue de la Cerisaie, ayant pour limite cette dernière et la place du Jardin-d’Alençay 3. rue du Côteau-de-Loire, à l’est de la rue de la Cerisaie et ayant pour limites cette dernière et la rue Marcel-Cachin 4. place du Jardin-d’Alençay pour l’espace public situé au nord de la rue de la Cerisaie, en limite sud du cimetière."