OpenStreetMap

Rostranimin has commented on the following diary entries

Post When Comment
Categorising paths about 1 month ago

Joost Schouppe - thanks - I'm glad to know that other people are continuing to think about this. While you'll be able to tell that I think I may have come up with a workable system (as proposed) I'm actually less worried about the detail and more about making sure that this gets sorted in a workable way one way or another. So long as people start worrying about this and testing ideas we ought to be able to sort it.

There's been one key thought knocking about in the front of my mind for the last week; we get away without having to worry about a categorisation of roads for one reason and one reason only. Someone else has done the categorisation for us.

There are all sorts of real issues with categorisation of roads, but the whole reason that any(many) of our maps make sense is because they are categorised. The categorisation always has flaws, and is always based to some degree on relatively arbitrary decisions... but we get away without having to worry about these arbitrary decisions because some official body has done this.

So we get to map lovely comfortable 'facts' and to pretend that opinions don't belong on OSM.

(I should say that I've come across a limited amount of discussion about the issues with road classification - but 99% of people seem quite happy that road classifications are used as a way to understand/draw maps and to influence routing algorithms.)

I was out again mapping recently - and once again found myself being absolutely forced to map my opinions rather than facts. Some paths had to be missed off the data because adding them would lead to confusion. In an effort to support clarity in mapping I had to decide what deserved to be mapped and what not... an arbitrary decision at the highest level - all because there is no way to categorise.

I now have a favourite path in mind as proof that we can't just map facts and leave categorisation to those rendering maps. On my local hills there's a path... it's about 8 metres wide at one point, is usually about 4 metres, and occasionally narrows to 1-2 metre. This happens over about 800m of path length. It's surface is primarily grass in terms of proportion of surface material. For much of its length what actually defines its use and appearance is that short but significant sections are very muddy. The muddy sections dry up for some short but relatively significant (but variable) periods in summer. The path is clearly not used ever for vehicles, but in other respects could be called a track (it's certainly wide enough). Early on the path is consistently grass, wide, and because the grass is firm it's not particularly obvious (being defined really by a line of new trees). Later the worn parts become gradually separate narrower paths which are too close together and too complex and too numerous to map individually, but the grass is no longer used for walking on.

The key question is: how do we tell potential path users something useful about this path?

We cannot map the facts (using a human mapper and working at the scale that OSM recognises at least). This is entirely an impractical idea. There are not even any average facts which help.

I can put things into simple words which define it well though.... this is a wide key path, created by wear by walkers, cyclists and horses, initially on smooth firm grass, later with significant usually muddy sections, and later deeply rutted with surrounding rough grass.

Surely we can't continue on OSM to simply call this 'a path' and be happy with this?

Categorising paths about 2 months ago

I was surveying some paths today and wondering about this proposal while I did so. One thought was whether some kind of numbered score would allow for the creation of a hierarchy. So 2 points for an obvious path, 1 for indistinct, 0 for an invisible one. 2 for a wide path, 1 for a narrow path. 2 for a flat path, 1 for a gentle angle, 0 for a steep angle.... but then I started thinking that my original proposal brings in these things, but also surface quality and smoothness. Now it starts to seem far to complex: 2 points for good tarmac, 1 for a bit rough, and 0 for very rough (BUT we already know from the smoothness tag proposal that this is difficult to define). 2 for a bound surface, 1 for something loose or slippery, 0 for ??

Far too complex. Not memorable.

And one other thought - related to yesterdays comments. I was following woodland paths for a while. They were all woodland paths, but all very different paths. What was the main path and what was the informal hidden path was really obvious - but I can't currently tag enough data for anyone to easily see this on OSM. What strikes me is that in any one place a change in only one feature makes the difference - in this case the real issue was just something about how well packed the surface material was. Width stayed the same. The basic surface material stayed the same. As things stand if I map these paths nobody will be able to tell that some are key good paths and some little used.

Categorising paths about 2 months ago

Hi Joost Schouppe. (Please forgive the length of this reply and poor grammar- it's been a long day but I'm interested in your thoughts and want to comment this evening)

Route relations are good... I've used them a lot... but they serve a particular purpose I think. I can imagine that for a defined park it might be possible to use this system to say something useful - but I suspect that this starts to do something which is discouraged for relations (using them to categorise things rather than to map something definite which just happens to involve more than one feature). I also struggle to think how things would work once outside a defined area. Nice idea though - feel free to try to convince me/others further here if you like.

The proposal to name a set of path types as Sanderd17 suggests also appeals as I said earlier. But after thinking more I can't think of a way to make this work in a sensible way. What we think would be a small set of path types I think would quickly mushroom into a very wide range of path types.

Unless someone can come up with around 6-8 categories (no more!!) which capture the kind of hierarchy that I'm aiming at. I don't think that ideas like 'forest path' and 'urban path' will work - they raise far too many questions I think. Scanning in my head through the areas I've mapped I don't see that I'd be much wiser... for instance I mapped a large park area on the West of Scotland which is on the edge of a small town but under woodland. You could call all of this urban path or forest path or formal path - some of it informal path or desire line or whatever. Fundamentally none of the sets of words i can think of would allow me to show you what the main paths are and what the faint desire lines are. Give me a bit of paper and I'll draw you what is the main path, what's secondary path, and what's fairly faint desire line... but I can't give you any sensible set of words to say the same thing (beyond what I just did).

Something like this would appear to work at first... primary path, secondary path, desire line, but it gives absolutely no information about path quality (so a primary path in one place would be a tertiary or secondary path elsewhere). And what happens when what is a primary path in one place becomes a tertiary path as it enters an area where it's not changed but it's no longer the primary path. I would like to think that something like 'formal_prepared_wide_flat_path' and 'informal_narrow_steep_path' would work (or simpler words to mean this), but I really can't find a way to do what I think is necessary.

Can someone come up with the necessary categories? If the categories are to be simple they ought to be simple to conceive of and fairly easy to agree on.

You're right that my system is intentionally hierarchical... so as you identify it asks us to accept that the 'unobvious' nature of a path takes precedence over everything else (whether it's walkable or usable by wheelchair becomes irrelevant in the system). I concluded that this is an inevitable feature of creating a hierarchy. I do wonder if the hierarchy in my head is just the one in my head... would a competing system put walkability above obviousness for instance?

Improving the OSM map - Why don't we? [1] 2 months ago

You raise an interesting issue... I've been reflecting on this kind of thing quite a lot recently. I've been discussing the advantages and disadvantages of different mapping systems (maps, data, open data, etc) - often in conversation with people who aren't converted to see why OSM is useful. I'm now very much in the habit of saying that OSM is "just another tool". I want to make clear that sometimes we should look to OSM, and other times we should look to another data/map source (Ordnance Survey being the obvious one discussed in the UK). The point is that these are different data sources... each with their advantages and disadvantages. When I want to know the precise location of something at street level, then (if the data is up to date) I go to the most precise Ordnance Survey data. When I want to know what paths and cycle paths are considered important in a town I start with OSM.

My point... OSM is what it is precisely because of how it works. This means that some things will be imperfect and potentially really really irritating. But it is what it is because of how it works. So we should do our best to improve the irritating stuff, but if it can't be fixed then we need to learn to live with it. I have a list of really really big irritations with OSM, but I also use OSM mapping as my preferred navigation tool when on a bike because it's the best source of information.

The beauty (and pain) of crowdsourced data and open source (etc)....

Categorising paths 2 months ago

That's a really interesting line of thought Scruss. I tried to write the proposal so that it would work internationally, but I'm painfully aware of having little or no proper awareness of worldwide differences in OSM tagging. I'm not thinking of English speaking nations really when I say that - I'm thinking that very different things could be going on in non-English speaking countries without me being aware. I did ponder looking through other language versions of the wiki documentation armed with Google Translate... but haven't tried yet. Could it be that elsewhere people have been developing good ways to tackle the issues I've raised?

Categorising paths 2 months ago

Thank you :-)

Categorising paths 2 months ago

Hi Little Brother

Your comparison to paper maps is really interesting... because actually I think there actually is a hierarchy used on such maps. The choice of what paths to show and what paths not to show is/was made for each particular scale of map, each map according to its purpose. What's different here is that we're trying to record the data which others then use to create those maps. So once upon a time a person (or at least a member of a team or organisation) would have surveyed with the final product in mind (a direct connection from surveyor to map maker)... but now we're doing something very different... there's very little connection between the surveyor and the map maker. Therefore the surveyor has to record enough information to allow the map maker to be able to choose what to include and what to exclude.

Typical hikers, I agree, won't look for the data I'm suggesting should be recorded... but those creating the maps (or equivalent services) for the 'hikers' potentially will do so... allowing them to produce a map at a high scale showing a city park and all the paths within it suitably rendered according to significance (for example), or a map at a low scale showing a whole city, and only the main paths in that same park.

Categorising paths 2 months ago

Peter - very valid thoughts. I learned myself often from looking at what others had done... but my argument is going to be that if there isn't a simple way to tag (primary, secondary, etc) which corresponds to well recognised ideas (in the UK, A road, B road, etc) then we have to either do nothing (rely on tagging objective facts) or to do our best with some simple categorisation... even if it's not ideal. It might be valid to argue that adding the word 'grade' ('category'?) to each category makes things clearer, but I couldn't make this into something sensible for my proposal ('grade_a2' isn't much clearer than ''a2' and raises lots of other issues.). After all it doesn't matter if paths are added without a grade... (beginnner mapping).

Categorising paths 2 months ago

Really interesting thoughts... I'd like to see that idea developed to see if it would work better than my suggestion. My worry would be that there would have to be too many categories... as a surveyor I find that this kind of tag only works if the categories are really easy to remember. Maybe take a look at the photos I provided in the proposal... can these be categorised sensibly in the way you discuss?

Nik4: mapnik → image 12 months ago

My suggestion would be to add some text directed at the ordinary OSM user/mapper. I'm one of those :-) I understand what Mapnik is, I understand the basic challenges of getting OSM mapping into a georeferenced image, I'm a pretty experienced mapper (years of involvement). BUT I don't have enough information here to understand whether this is something useful to me. This isn't a criticism - I realise there is a lot still to learn and that the onus is on me to do this - but some plain English words explaining what to you are utterly obvious things would help people like me (to whom they aren't obvious). Note that I'm not asking for more than a few sentences - that should be enough. Thanks.

Google Map Maker about 2 years ago

Interesting - but I think that's beside the point (we could get into a discussion about this without getting anywhere useful - and I'm writing partly based on my personal experience of both systems which is of course personal...) - there are many other examples in any case. My point stands - in a 'free market' it's not necessarily the best design which wins where there's competition.

Google Map Maker about 2 years ago

The target group I have in mind is definitely different from these two - it's people who want to use the map/data in the simplest ways.

This group is huge I think. It would include: John who wants to drive to a conference somewhere new. Jake who wants to know a good cycle route to his workplace. Jane who wants to check where the nearest Tesco store is. Janet who wants to print a map of her local area so she can show a friend where her new house is. Jackie who is trying to find her way around a strange city by bus. Jack who wants to see what rivers he could paddle a canoe on. Jo who wants to know the name of the odd building near her office.

None of these people initially come to the map to contibute data... but they all have the potential to do so. None of these people necessarily have any technical ability, beyond that required to navigate Google Maps.

Google Map Maker about 2 years ago

Aha, Richard, you're the Switch2OSM person. Very nice site. I've been close to creating an equivalent for new map users a couple of times... those just wanting to find their way around... but I've not quite found the time. Again, I don't think it's that huge a job, and would certainly be worthwhile if people took notice of it.

Unless you fancy adding something on this to Switch2OSM??

Strangely we seem to be stuck between (at least) two points of view. One says "this is data, not GM, not for finding your way around, so it doesn't need to be friendly to people needing this." The other says "this is a map project and should have a map on the front page like GM."

Ideally a combination of both the German system and the current one would be great - but technically harder I'm sure. A map on the front page yes, but without making people think that the one page is the totality of OSM - in fact making sure that they know that they need to dig a bit to make the most of OSM.

I suppose my starting point is that the German page needs work - but that it's SO much better than our current one...

Google Map Maker about 2 years ago

Richard - thanks for your comments. My main motivation for posting the original diary entry was to add to the motivation for change, not just to moan... so I'll certainly look up the suggestions.

As you say, this isn't easy... at least I think it IS easy, but only once people are motivated, and only once a big enough group understands why it's important. I had a go at adding improvements to the beginners documentation some time ago (just at the time that the phrase 'or some of the many other services' was added to the front wiki page), but became completely frustrated as easy language was converted repeatedly back to more technical/involved/detailed information.

For clarity, I'm not necessarily advocating advanced functionality on openstreetmap.org. One of the best things about OSM is that it doesn't depend on one page... what I'm pushing for is that the first encounter with OSM tells people this. That's not such a difficult thing technically.

One thing I'd like to suggest - if it were technically/politically possible - because this presumably would be technically simple - is that openstreetmap.org simply adopts the German front page (translated of course). Surely this ought to be possible?

Google Map Maker about 2 years ago

People keep saying that OSM is better. That's to miss the point. It's very much better... but GM is very very much more popular... by which I mean that interaction with GM is something which is part of the habit of a very large number of people. And it does some things stunningly well (Streetview particularly). This means that if people can accomplish things using GM they will - even if it would have been better accomplished using OSM. Right now that's not a problem, because most of what can be accomplished with OSM can't with GM, The real point is that as what can be accomplished using GM grows (it's growing steadily and shows no sign of stopping) the risk to OSM increases dramatically. OK maybe it'll not die completely - even Betamax video recorders retained a small geeky fan base long after the rest of us gave up on them...

Once again - my main point is that the effort to make OSM welcoming would be small and nothing at all would be lost! "We're not trying to be Google Maps" isn't a good reason for being unwelcoming.

And I'm not talking about 'contributing' mainly by the way - I'm talking about using the data. Recently I wanted to find my way about a new foreign city. That's where Openstreetbrowser (browsing OSM data) came in. It's a stunningly useful tool not for contributing but for browsing. Once you know what you are doing you can very very easily find your way around a city by public transport using this. Yes I know, there's a strong feeling among some that OSM isn't about finding your way around (I disagree) - but those finding their way around may well become contributors. I only started contributing once the map was worth using - I had no interest until then. Now I'm an enthusiast.

Is there any reason why we shouldn't be welcoming to ordinary people who just want to find their way from A to B? What could we lose by doing this? Nothing?

Google Map Maker about 2 years ago

Nice to have comments :-)

My point is that GM is starting to move towards fulfilling (badly just now) the same needs as OSM. I disagree profoundly that GM fill fail on this ground - it's building on an extremely strong customer base (as with the example I gave). This easily trumps the fact that OSM is better, that our data is free, that OSM isn't just a map but open data, etc etc. GM also has a strong commercial interest in moving into the space that OSM currently fills - taking up the competition that OSM has begun (I disagree that they fulfil different needs - perhaps just now they do, but GM is coming to get us, that's how competition works). It WILL move gradually into this space unless OSM increases its customer base. The only way for this to happen is for OSM to become welcoming and friendly to non-OSM people. To invite people in. To showcase its value not to hide it away for specialists (or a few people taught by specialists).

The reason I sound irritated by this (nothing personal intended - its a long term irritation) is that becoming friendly and inviting to non-OSM people really wouldn't be hard, and because nothing would be lost by doing this.

What's lost by having a front page like the German one? Or something even better?

Google Map Maker about 2 years ago

You can't can you? No argument with OSM being better!

impassable gate? over 2 years ago

Actually scratch that comment about putting 'access' values on the road - there's no good reason why it shouldn't be on the gate itself.

impassable gate? over 2 years ago

That looks pretty good. I like the thing about giving it a default. The only real issue might be that the access ought (I'd have thought) to be tags for the road/path not the gate. Perhaps I just have to get on my bike and investigate the other end of this to find out if I could do that... (if there is a similar gate at the other end it makes things simpler).

impassable gate? over 2 years ago

Opening hours might do it - although from the wiki entry this is more aimed at the idea of something being open to customers (rather than open for passage). I wondered about 'access' but that's aimed at the legal status of something and that I don't know about.

It doesn't help that I don't really know what's on the other side of the gate (other than what's mapped) having never been through it (only passing by on the road).

My concern is mainly that this looks (on renderings, but probably to routers too) like it's a viable cycle route / walking route when this is normally not the case... the 'tall' comment is irrelevant really, what I was aiming at was to explain that when the gate is closed you aren't going to get past (at least not without climbing equipment!). Gate is locked most of the time (except a for a few hours a couple of days per week).