Over the last few weeks I’ve improved the way that paths and tracks are shown on map.atownsend.org.uk in both the raster and vector versions. The aims were:

1. Improve clarity, so that their visibility in e.g. nondescript woodland was better
2. Improve consistency, so that the display of them on vector and raster looked similar to each other, and the “visual weight” of each class broadly matched when looked at together on a map.
3. Reduce confusion so that two different things were not shown in similar ways.
4. Show “good quality” paths and tracks (e.g. paved and compacted gravel surfaces) differently to other ones to help answer the “will it be muddy” question.

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Generally speaking, Lifecycle Prefixes mean that when something is no longer in use, a tag such as amenity gets changed to disused:amenity. That should be straightforward, but sometimes disused=yes creeps in.

This example overpass query for nwr["amenity"="fast_food"]["disused"="yes"]({{bbox}}) finds a couple of examples. In these cases we can have a look at the tag history and (as seen in the picture at the top) notice that the FHRS ID changed recently, and the disused=yes actually corresponded to the name of a different business on the same site (in fact that that one has the full set of such tags: ["amenity"="fast_food"], ["disused:amenity"="fast_food"] (which don’t make sense together) and ["disused"="yes"]. In these cases you can often look through the tag history and see what the current status is supposed to be; if the last changeset comment was “this has now closed” it’s fairly obvious.

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Because sometimes you want to see less rather than more, I created this. It’s the railway information from the existing transportation layer of the SVE01 schema, together with railway stations, places and water as needed for context.

One thing that it does is to distinguish between regular transportation railway stations and tourist ones.

Freight lines are de-emphasised (see here and disused and abandoned railways are shown in a barely-discernable grey.

The source of the style is here but that is just a subset of the “show everything” style for this schema here.

The problem

I’ve been creating and serving web-based maps such as this one for some time. That’s based on raster tiles, and an osm2pgsql database is used to store the data that the tiles are created from, on demand as a request to view a tile is made.

For various reasons I wanted to also create a similar map using vector tiles. With vector tiles what is sent to the client (such as a web browser) is not lots of small pictures that the client stitches together, but instead larger chunks of data, still geographically separated. The client then creates the map itself based on the style that it has been told to show the data in, combined with the data itself.

I’d noticed that the vector maps that I was displaying were sometimes slow to load, especially at some lower zoom levels such as vector zoom 8. Note that vector zoom levels are one less than raster zoom levels, so vector 8 is raster 9.

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Many people have noticed that publicly available Overpass servers have been suffering from overuse (a typical “tragedy of the commons”). OSM usage policies generally contain the line “OpenStreetMap (OSM) data is free for everyone to use. Our tile servers are not”. Unfortunately, there have been problems with overuse of the public Overpass servers, despite the usage policy. “Just blocking cloud providers” isn’t an option, because (see here - use the translate button below) lots of different sorts of IP addresses, including residential proxy addresses, are the problem.

People who want to use e.g. Overpass Turbo do have the option to point it at a different Overpass API instance. If you’re using Overpass Turbo and you get an error due to unavailability, likely that is because the Overpass API that it is using is overwhelmed. There are other public Overpass API instances, but they may be complete (in terms of geography, or history) or up to date.

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… railway departure boards in pubs.

A surprising number of pubs near stations in the UK have them now. The picture above (a detail from this Manchester Evening New article) is from the Victoria Tap in Manchester.

A search of the OSM data in the UK** finds a few, but I’m sure that there are more. A web search finds a bunch of suppliers, and many of their “here’s what you could have in your pub” examples are clearly in the southeast and southwest of England, so I’m sure that there are more to be mapped!

** That’s a simple postpass query:

{{data:sql,server=https://postpass.geofabrik.de/api/0.2/}}
SELECT osm_id, tags, geom 
FROM postpass_pointpolygon
WHERE tags->>'amenity'='pub' 
AND tags->>'departures_board' is not null
AND geom && {{bbox}} 

I look after a map style that’s designed to show rural pedestrian-focused information (hiking routes etc.). It natively supports zoom levels up to raster 24 and vector 26 (which is equivalent to raster 27), which means that small things like fire hydrants and manholes can be shown at high zooms without getting in the way of everything else. The raster and vector versions differ slightly, partly for technological restrictions (finding out “which routes this guidepost is part of” is easier on vector than raster).

A big question, though, is how do I find out what is missing? The styles evolved from an overlay for the the OSM Carto raster style in 2014 and have been added to ever since. However, the things that people map in OSM has increased a lot in that time. Sometimes I spot something obvious that’s missing, but how do I make sure that I haven’t ignored some relatively high-usage and important tag?

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The https://www.openstreetmap.org website currently has two “OSM-hosted” map styles on it - the “Standard” style (raster tiles) and a “Shortbread” one. The schema for “Shortbread” is here, and the display style shown is “Colorful” from Versatiles. It looks like this:

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… and following on from the previous entry, Maps for Garmin devices at map.atownsend.org.uk now show crossing details too:

The following tags from the top-level feature are shown:

• traffic_signals or crossing
• The value of crossing if it adds extra information
• The value of crossing:island, crossing:marked, crossing_ref etc. if they add extra information.
• Information from tactile_paving and kerb.

All of this might be truncated for length (it is here), but the most important information does appear.

I have a couple of web maps, and they are supposed to show pedestrian crossings. If there’s some crossing infrastructure (for example - zebra stripes, or tactile paving and a lowered kerb) you’re supposed to see a “crossing” icon. If there are traffic signals associated with the crossing, that icon should be replaced with a “traffic signals” one.

Years ago it was straightforward - you’d get a highway=crossing tag on a node on the roadway, and there would be another tag, such as crossing_ref to say what sort of crossing it was. Some crossings (such as pelican, puffin and pegasus) have traffic signals; others (zebra and informal crossings) tend not to.

Unfortunately, it has got a lot more complicated.

Sometimes, the highway tag is crossing;<something> or <something>;crossing. Sometimes that something should be ignored and treated as a crossing.

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The vector tiles here have always had names in “the local language”, so Welsh-speaking parts of Wales have Welsh names shown and English-speaking parts English names:

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There are a number of ongoing discussions about the geocoder on osm.org (Nominatim) in the forum at the moment. These include spelling tolerance, how it might work with data that does not exist in OSM yet and what it actually returns.

Sometimes the results of the last of those can be a bit odd. Here for example is a post office not far from me. The returned data (“Stillington Post Office & Stores, Main Street, Stillington, York, North Yorkshire, York and North Yorkshire, England, YO61 1JS, United Kingdom”) has three things that could plausibly be a county in there - York itself, North Yorkshire, and York and North Yorkshire. In OSM these are respectively a nearby place=city node, and encompassing admin_level=6 and admin_level=5 relations.

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tl;dr: slightly less than an hour.

This was prompted initially by a forum comment (I can’t actually remember exactly where or by whom) that creating maps based on OSM was for “developers” and not “normal people” (not in those exact words), and by the thread here. The “slightly less than an hour” actually includes setting up a development environment from scratch on a new PC.

On that new PC I’ve already installed a text editor and a web server (“apache2”).

cd ~/src
git clone https://github.com/SomeoneElseOSM/SomeoneElse-vector-web-display
git clone https://github.com/systemed/tilemaker

In the first of those repositories there are a selection of map styles, including one that uses the OSMF demo vector tiles. Let’s first test that that works:

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Kex Gill (humorously named the “Côte de Blubberhouses” for a stage of the 2014 Tour de France) is a road in Yorkshire between Harrogate and Skipton. Part of it is gradually sliding down the valley that it is built half-way up the side of and is being rebuilt; it was the access tags on bridleways there that caught my eye in the first place.

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I recently updated this map:

and this one:

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The diameter_crown tag is fairly well used for trees. It’d be nice when showing trees to show larger ones as larger than smaller ones. One challenge is that the values can be a bit hit and miss. There are a couple of sorts of issues there:

One is “obviously silly values from an import gone wrong” like the 289 diameter_crown=width: 2.0; color: green; that have found their way into the database, perhaps by a failed JSON conversion.

Another is “human but not machine readable values” like “4 - 7 m”

Another again is implausible values for certain tree types. For example, this is apparently a London Plane that is 5 times wider than it is high. That’s technically possible with a bit of pruning, but unlikely. Much more likely is that the data was not sanity checked before import, and the “diameter” figure here is actually a “circumference”.

In order to work around these issues, when processing the data prior to display I:

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Lots of people use editors such as iD, Potlatch, Vespucci, GoMap!! etc. for editing. There are entirely sensible reasons for this - I’ll always try and edit relations in Potlatch or iD since for me editing relations there is a much saner experience than in Josm. However, one thing that they miss is Josm’s Validator, which can check for relation errors that other editors can’t. Here’s how to use that to detect problems, and then fix them elsewhere.

I’ve created some test data on the dev server for this, so that I can deliberately create and fix errors. If you want to test with that data on the “dev” server, you’ll need to create an account there and tell Josm to login to that server - or you can just look at the screenshots below.

First, you’ll need to download Josm (I just downloaded the latest .jar file) . Josm’s user interface will be familiar to anyone who used CAD software in the 1980s, but may be less so to others.

Then you’ll need to download some data in the area that you were editing (file / download data / download). So that you can see what is where, it helps to have a background layer - “OpenStreetMap Carto (standard)” will work, or you can use an imagery layer if you prefer. Zoom in to your area of interest, select with the mouse and “download”.

Then click “validate” (on the row at the very bottom right of the screen). If “validate” does not appear, then “Help / Search Menu Items / Valid”, click the entry that appears, and click OK. The “validation results” area should apear with the big “Validate” button with a tick on it.

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I maintain a web map style that shows walking and cycling route names. For the cycle routes, it shows the ref. For some time I’ve massaged some of the names so that e.g. National Byway loops show as “NB (loop)” just like on the signage. However, as can be seen from the example above, some hiking route names are a bit convoluted - they’re more like descriptions than names.

For example, osm.org/relation/3971851 is the England Coast Path. Open up the list of members to see the names, which includes such delights as “King Charles III England Coast Path: Southend-on-Sea to Wallasea Island”. I’m pretty sure that it doesn’t say that on the signs there.

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I created this for my own use, but am sharing it here because it might be useful to other people too. This is the style and there’s a brief readme.

It uses different colours to highlight different map layers. It’s not supposed to look nice; just to show you what is there.

I believe that everything described in the schema is included. If a feature does not appear it might be because:

• it’s not in the Shortbread schema.
• it’s in the schema, but is for some reason missing from the OSMF vector tiles.
• it’s in the tiles, but there’s a bug in this style.

There are lots of features in the first category, and there seem to be a couple in the second. If anyone finds anything in the third category please let me know!

Recently, there’s been quite a lot of discussion about the problems with using the tag “highway=path” in the forum. See for example threads here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, here and here - and that’s only the last month or so!

It’s not descriptive

On it’s own, “highway=path” doesn’t really say anything other than it’s somehow possible to get from one end to the other. Have a look at the pictures in the wiki - all of those are regularly tagged as “highway=path” in some regions.

There are some really bizarre examples out there. Up the Hillary Step to get to the top of Everest? highway=path. A scuba diving route? highway=path.

While it is possible to add extra tags to say a bit more about the feature being mapped, often this simply isn’t done.

A data consumer (map maker, routing app creator or even just a human deciding whether to go for a walk somewhere) can’t tell what they’re going to find.

It’s impossible to tag the legal situation properly

The idea is that you can tag a path for pedestrians as “highway=path; foot=designated” and one for cyclists as “highway=path; bicycle=designated”.

The problem here is that “foot” and “bicycle” are “access” tags, and these aren’t always “yes” or “no”. Valid values might be “customers”, “destination”, “permissive” amongst others. If the “foot=designated” on a “highway=path” implies “foot=yes”, what should the tagging be if only customers are allowed?

In countries with some form of allemansrätten (much of Scandinavia, some other places in Europe, including Scotland) this is less of an issue. If you know you can go pretty much anywhere you don’t need to explicitly tag “foot=yes” on everything, and tagging “highway=path; foot=designated” isn’t a problem.

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