[Talk-GB] UK Project of the week - trace a village off of OSSV?

[Kai Krueger]

Hello everyone,

I would like to suggest as a sort of "Project of the week" for the UK 
for people to pick a random town or village somewhere in the UK that so 
far has poor coverage and trace it's roads from OS OpenData StreetView.

Despite the various claims over the years that the UK road will be "road 
complete" by the "end of the year", the UK is still a far distance off 
of that target. I have heard the numbers that so far we have on the 
order of 50% of named roads (people who are working on OS - OSM 
comparisons please correct me if I am wrong). Which is by no means a 
small feat of achieving, but also not as high as one would like it to be.

So let us try and accelerate this a bit by everyone picking a small 
random town or village somewhere in the UK and trace the roads from 
StreetView. It probably only takes about 10 - 20 minutes for a small 
village and even a small town isn't too bad to do (if the weather is bad 
and you can't go out). So with the help of OS data, we can get a big 
step closer to where we would like to be and use it as a basis to 
continue to improve beyond the quality of OS data or any other 
commercial map provider.

(If you are convinced already, then no need to read the rest of the email)

I know that many people are opposed to "armchair mapping" or imports 
(and btw I am not proposing a full scale import here, but manual tracing 
instead) and so I'd like to counter some of the arguments most likely 
going to  be brought up against this sort of non local tracing:

1) OS data might have mistakes, be outdated and generally not as good as 
what OSM aims for: Yes, no doubt OS has errors and can be outdated in 
many places by a couple of years ( I have found more than enough of 
those myself). Furthermore, all of the OS products released lack many of 
the properties we are interested in like one way roads, turn and other 
restrictions, POIs, foot and cycle ways and all the other things that 
make OSM data such a rich and valuable dataset. So yes, the OS data will 
clearly not replace any of the "traditional" OSM surveying techniques or 
be the end of things. But it can be a great basis to build upon.
As a comparison, have a look (assuming you have a timecapsal ;-)) at 
what the data of e.g. central London looked like in 2007. It already had 
surprisingly many roads, but hardly any POIs or other properties that we 
aim for now. Most of that came later in many iterations of improvement.
A single pass of "OSM" surveying is not any better than the OS data per 
se. Also given that the errors introduced by tracing OS data are exactly 
the same type of errors introduced by manual "OSM" surveying, i.e. 
misspellings in roads, missing roads, outdated roads, ... We need to 
have the tools to deal with this kind of maintenance anyway.  It is the 
iterations that make OSM data what it is, not the "first pass ground 
survey".
Creating a blanket base layer from OS data allows us to much better 
focus on the aspects that do distinguish us from every other map data 
provider with having to "waste" as little as possible resources on the 
"stuff everyone else has" too.

2) large scale imports and tracing hinders community growth: This 
perhaps is the more important of the two arguments, as indeed what 
distinguishes us from everyone else is the community and without the 
community and its constant iterations  and improvements, OSM data will 
"bit rot" just as much as all other data. However I don't think there is 
any clear evidence either way of what non local mapping does to 
communities and it remains hotly debated. The negative effects claimed 
are usually of the form a) The area looks complete, there is nothing 
more to do, so why bother. Or, it isn't as much fun to add a POI than a 
whole new village on a blank canvas. b) I put in all this effort into 
mapping an area and along comes an import and steam rollers all this 
into a mess, I am leaving. c) imports introduce a new class of bugs, 
e.g. duplicate nodes or broken connectivity that OSM mappers wouldn't so 
we don't have the tools to deal with these sort of errors correctly.
b) and c) are specific to imports and thus manual tracing shouldn't 
suffer the same issues. a) may be the case, but it is clearly a case 
that we need to be able to deal with anyway, as more and more areas 
become "complete" by "them selves". And looking at the better mapped 
areas, like Germany or some of the UK cities, I don't think there is any 
evidence that you can't attract new comers into already mapped areas. It 
is potentially also offset by all those people who simple want to use 
the data for something like embed a map into their blog or use OSM data 
on their Garmin, their phone, their game, their ... and will fix the odd 
bug they discover while doing so, but can't really as it simply isn't 
complete enough yet.

Other examples of remote mapping have also been fairly successful. The 
most obvious one was Haiti. It's initial phase was entirely arm chair 
mapping and had no community at all. Only later followed by on the 
ground surveying. Never the less it is generally considered a success 
and has gained OSM many new mappers.

The other example is mapping during holidays. Lets say I go and visit a 
mostly unmapped island in Scotland. I'll be able to survey a few roads, 
add the odd POI make a few mistakes and miss many details. I will also 
never return to that place again to fix up any bugs I might have 
introduced. Should I not have mapped during the holidays as I wasn't a 
"local mapper" or part of the "local community"? If I do it in a foreign 
country, I might not even no the local laws.

So again, we as a community as a whole need to be able to deal with 
these sorts of issues that also arise from armchair mapping and it is a 
great test for our ability to create appropriate quality assurance tools.


Anyway, far too much rambling from my side already, so I better stop now 
again. I just felt like countering some of the general negativity 
towards armchair mapping and imports.

Kai