Re: [Talk-GB] OS StreetView accuracy: caution!
Is using the source:OS_OpenData_{Product} tag good enough as a caveat? Or
should we also add FIXMEs? When I started I used both, but now as the tag
structures for the OS OpenData seems pretty solid I removed the FIXMEs and no
longer add them.
The one time I can think of using a FIXME in addition to the OS tags is for
roads which look like service roads in the OSSV data, but there's no indication
of their surface type. I add a FIXME if I don't know the surface type myself.
Or do we just assume that the OS tags are sufficient ad that people will know
that these should all be surveyed/checked on the ground?
Cheers
Tim
--- On Sun, 11/4/10, Dave F. dave...@madasafish.com wrote:
From: Dave F. dave...@madasafish.com
Subject: Re: [Talk-GB] OS StreetView accuracy: caution!
To: Tim François sk1pp...@yahoo.co.uk
Cc: talk-gb@openstreetmap.org
Date: Sunday, 11 April, 2010, 2:39
Tim François wrote:
I think OS *is* more accurate on the whole,
I think you're probably correct, but the problem arises
when we *assume* that it's more accurate in areas where
we're not knowledgeable of what's on the ground.
That's not to say we shouldn't map, but I think we should,
as we've been doing before, tag in caveats using the fixme
or notes tag to say we're uncertain of certain areas.
Cheers
Dave F.
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Re: [Talk-GB] OS StreetView accuracy: caution!
On Fri, 9 Apr 2010 19:00:43 +0100 Kevin Peat ke...@kevinpeat.com wrote: It seems odd to me that we are encouraging people to contribute using often pretty rubbish mobile phone gps receivers but complaining that the OS data is not sub-metre accurate. I don't think sub-metre accuracy is what anyone is concern about when it comes to Street View. I think it is generally accepted that OS has very high precision (at least provided the map or data set is used at the scale for which it is intended). The accuracy concerns raised have generally been about whether mapping is up-to-date or contains other errors. I don't think anyone here is saying don't use the OS Opendata stuff*, just urging sensible caution in its use, just as sensible caution should be used when using any other secondary source, or indeed when relying on GPS traces! An example of not being cautious might be seeing that a road on OSM has a different name than it does on OS, and changing OSM even though it is clear the road name in OSM comes from a ground survey, without doing your own ground survey to verify. David * I do have some concern over compatibility with the ODBL, but I think I am in a minority of one, and I haven't had a chance to examine thoroughly enough, and IANAL. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
Tim François wrote:
Is using the source:OS_OpenData_{Product} tag good enough as a caveat? Or
should we also add FIXMEs? When I started I used both, but now as the tag
structures for the OS OpenData seems pretty solid I removed the FIXMEs and no
longer add them.
I think source:OS_OpenData_{Product} is fine for a general warning about
where your data came from, but if there's some entity you're really not
convinced about using the Fixme/note tags will fully clarify.
Cheers
Dave F.
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Re: [Talk-GB] OS StreetView accuracy: caution!
On Fri, Apr 9, 2010 at 7:00 PM, Kevin Peat ke...@kevinpeat.com wrote: On 9 April 2010 18:40, Robert Scott li...@humanleg.org.uk wrote: Hasn't one of OSM's (many) mantras been doesn't matter if it's approximate: someone can always improve it later or rough is better than nothing? Sure, some of the OS data is rough, but it is better than nothing, and quite good for a first pass. +1 on this. It seems odd to me that we are encouraging people to contribute using often pretty rubbish mobile phone gps receivers but complaining that the OS data is not sub-metre accurate. I think the point is not to assume that where OSSV and OSM disagree, that OSSV is necessarily the correct one. It might generally be, but if you can't go out and check, be very careful what you do. If it's just how curvy it is I generally find checking the OSM GPS traces is a good idea, because you often find the GPS trace just hasn't been followed very well. Maybe some people will be put off if the empty areas are filled in with OS data so they don't have a blank canvas but I bet there are just as many people out there not knowing where to start who would add street names and POIs and clean-up any OS errors. That's a very good summary. By far the most important thing is not to leave a mess. Dave ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
Tim François wrote: I think OS *is* more accurate on the whole, I think you're probably correct, but the problem arises when we *assume* that it's more accurate in areas where we're not knowledgeable of what's on the ground. That's not to say we shouldn't map, but I think we should, as we've been doing before, tag in caveats using the fixme or notes tag to say we're uncertain of certain areas. Cheers Dave F. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
On Thu, 8 Apr 2010 15:03:19 +0100 Phil Monger phil...@gmail.com wrote: Streetview is a product designed to show *streets. *Anything else is just detail to show these in context. I would have to agree with you there. I have been surprised at just how out of date POIs can be compared to other OS maps., especially in rural areas. E.g., this post office closed a good 20 years ago: http://edgemaster.dev.openstreetmap.org/streetview_tiles/ossv.html?zoom=16lat=52.41902lon=-2.92639layers=BTF This has gone from the Landranger, but not Streetview. I'm sure this is not an isolated example. So definitely a need for caution. I can suddenly feel my motivation for mapping coming back :) Nevertheless, my favourite OS FAIL remains the PRoW through a vat of sewage on the Landranger (courtesy of Bing): http://bit.ly/bHhDwW Whether this is the OS's fault or the council's I am not sure (the Council have put up new waymarks, though). The footpath does follow roughly (I had a very poor GPS signal that day) its revised course in OSM. Not trying to knock the OS, by the way. I love the Landranger maps, it is just reassuring to know that even the great Ordnance Survey can't get it all right. David ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
Oops, think that was actually an OS Explorer. Pretty sure it's the same on the Landranger. David ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
On Fri, 09 Apr 2010 13:57:40 +0100 David Ellams osmli...@dellams.fastmail.fm wrote: Hello David, it is just reassuring to know that even the great Ordnance Survey can't get it all right. By their very nature paper maps, like telephone directories, are almost certain to be out of date before they're published; New roads get built, people apply for a variance on a ROW, Post Offices shut, etc. -- Regards _ / ) The blindingly obvious is / _)radnever immediately apparent No you can't hop into my shower Leave Me Alone (I'm Lonely) - P!nk ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
Try searching for Blackbushe Airport On Fri, Apr 9, 2010 at 1:57 PM, David Ellams osmli...@dellams.fastmail.fm wrote: Nevertheless, my favourite OS FAIL remains the PRoW through a vat of sewage on the Landranger (courtesy of Bing): http://bit.ly/bHhDwW ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
On Thursday 08 April 2010, Phil Monger wrote: I'd echo that sentiment, and say this: Streetview is a product designed to show *streets. *Anything else is just detail to show these in context. It would be a huge mistake for anyone to trace topo details from StreetView into OSM, for these reasons and more! I do think though, that it is an excellent source of street and road information in areas that have not yet been traced ... as long as users don't get over zealous with it. I'm not really sure about this whole attitude of OS data is not perfect, so let's ignore the imperfect bits. The reality is - for the majority of the data in, for example, StreetView, OSM's corresponding data is - nothing. The huge majority of buildings in SV are just plain not there in OSM. Most rivers streams in OSM around the country have, frankly, probably already been derived from an OOC OS source in the first place. Small placenames and farm names are generally not there, and again, have often previously come from OOC OS. Hasn't one of OSM's (many) mantras been doesn't matter if it's approximate: someone can always improve it later or rough is better than nothing? Sure, some of the OS data is rough, but it is better than nothing, and quite good for a first pass. A lot of the features I myself put in over the years ( I don't have aerial imagery available for my area ) turn out to be much rougher than that in SV. Again, I am not saying we should do a blanket countrywide import of anything, or even that we should decide what to merge until the OS is done releasing what it's going to release. robert. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
On 9 April 2010 18:40, Robert Scott li...@humanleg.org.uk wrote: I'm not really sure about this whole attitude of OS data is not perfect, so let's ignore the imperfect bits. I agree, and I'd go further The accuracy of OS data looks vastly superior to our data. Its always hard to keep track of discussions in OSM lists, but I can't work out the apparent attitude of many towards the OS data. It appears many who have given up 100's (1000's?) of hours to help create the OSM map don't want to see their work replaced by more accurate OS data, and are looking for errors in the OS data? There seems to be an movement towards arguing OSM is about people going out and gathering data in the field, and not simply bulk importing other peoples info? This thread started off by mentioning errors seen in the OS map when out mapping the Centenary Way, but can we be sure the OS map was wrong? Handheld GPSr receivers can be out by 10's of meters. Looking at the Centenary Way route (from OSM) as kml within Google Maps shows we clearly have the route 'off the path', and in places it goes through water. Is that accurate? Download any OSM path/walkway/route and look at it using google aerial maps, the path is nearly always out. OS products wont be perfect, and should not be bulk imported, but the supplied data will still be more 'accurate' than the OSM Cheers, Jason ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
On Friday 09 April 2010, Jason Cunningham wrote: The accuracy of OS data looks vastly superior to our data. I'm not sure I'd agree with that either. We do have several places where we easily outdo what's so far been released. But we also have many areas where we have next to nothing. robert. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
I think OS *is* more accurate on the whole, after comparing a vast amount of areas with which I'm familiar. Yes, we 'outdo' the OS map in some areas, but probably not in accuracy, more in map 'awesomeness'. I still think that we should be tracing the blank areas with the OSSV data. I've done some and noticed that not all the street names are on the OSSV data. Thus, there's still jobs out there for those who love to go out and survey. Along with getting all the other yummy data such as street furniture, shop names etc. The two methods complement each other well, I think - I'll certainly continue to trace and survey! Tim P.S. I agree with most though on the bulk import - don't do it! --- On Fri, 9/4/10, Robert Scott li...@humanleg.org.uk wrote: From: Robert Scott li...@humanleg.org.uk Subject: Re: [Talk-GB] OS StreetView accuracy: caution! To: talk-gb@openstreetmap.org Date: Friday, 9 April, 2010, 19:17 On Friday 09 April 2010, Jason Cunningham wrote: The accuracy of OS data looks vastly superior to our data. I'm not sure I'd agree with that either. We do have several places where we easily outdo what's so far been released. But we also have many areas where we have next to nothing. robert. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
[Talk-GB] OS StreetView accuracy: caution!
I've just completed a 25 mile stretch of the Centenary Way in Warwickshire and I'm editing now with the aid of OSSV. Generally it's accurate but I've found a track on the wrong side of river and the course of a stream crossing my GPX tracks from the footpath where the footpath clearly stays on one side of the stream. And often there are gaps in waterways where there are none on the ground. I'm sure I'll find more as I continue editing. Also I've had a look at major building outlines in Birmingham - some of which have been demolished. So be careful with the data - it still needs a survey! Regards Brian ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] OS StreetView accuracy: caution!
I'd echo that sentiment, and say this: Streetview is a product designed to show *streets. *Anything else is just detail to show these in context. It would be a huge mistake for anyone to trace topo details from StreetView into OSM, for these reasons and more! I do think though, that it is an excellent source of street and road information in areas that have not yet been traced ... as long as users don't get over zealous with it. On 8 April 2010 09:14, Brian Prangle bpran...@googlemail.com wrote: I've just completed a 25 mile stretch of the Centenary Way in Warwickshire and I'm editing now with the aid of OSSV. Generally it's accurate but I've found a track on the wrong side of river and the course of a stream crossing my GPX tracks from the footpath where the footpath clearly stays on one side of the stream. And often there are gaps in waterways where there are none on the ground. I'm sure I'll find more as I continue editing. Also I've had a look at major building outlines in Birmingham - some of which have been demolished. So be careful with the data - it still needs a survey! Regards Brian ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
