[Talk-GB] Summer quarterly project
SK53
sk53.osm at gmail.com
Tue Sep 13 11:32:47 UTC 2016
My comments on both suggestions:
- Speed Limits: a little bit boring, *BUT *there are some relatively
achievable targets. For instance getting all primary & trunk roads with
speed limits. There are areas of the country where none of these roads have
limits, but even in well mapped places there is a considerable amount of
simple tidying up (missing speed limits on roundabouts or short sections)
which can be done. A further advantage is that major roads are also more
likely to have Mapillary/OpenStreetView coverage. Additionally things like
number of lanes, availability of pavements etc can be added as well whilst
reviewing speed limits. I noticed this a few weeks ago because back in
September last year I drove to Bewdley & waypointed changes of speed limits
on the A456 from Hagley to Kidderminster.
One additional caveat is that speed limits on the narrower roads are
changing a lot: national speed limits to 50, 50 mph down to 40 mph, etc.
I've noticed this particularly along the A606 as travel this by bus about
once a year when I take more mapping notes.
I have put a map based on this <http://overpass-turbo.eu/s/imj>
Overpass-turbo query on Flickr <https://flic.kr/p/LJuZiC> for trunk
roads missing speed limits, and one for primary roads in the East Midlands
here <https://flic.kr/p/M1tzcj>. The latter query
<http://overpass-turbo.eu/s/imi> returns too much data for the whole of
the country but can be tailored by changing the area part of the query.
- Food Hygiene data. This would be in two forms: enrichment of existing
OSM data (primarily with addresses); and surveying areas which have lots of
FHRS data but little in OSM.
The former is a valuable, but not particularly gripping activity. IIRC
the FHRS data covers somewhere between 10-15% of total postcodes, and just
having one address in a postcode can help resolve many adjacent ones. Two
addresses and one can infer properties of how addresses are allocated on a
road.
Last year Peter Reed wrote a long series of blog posts
<http://tlatet.blogspot.co.uk/2015/08/osm-retail-survey-conclusions-1.html>
about retail data and used Super Output Areas to predict volumes of missing
data from OSM. Last year I targeted Melton Mowbray, Coalville, Havant and
Chichester for mapping of the town centres based on this data. More
recently I've done Hoylake & New Brighton. I'd hoped to have a look at
Hyde, Tameside at the weekend, but was too tired by the end of the field
meeting. Most towns in Greater Manchester are ripe for this kind of
mapping: Oldham, Rochdale, Hyde, Denton, Ashton-under-Lyme and many others.
In the past I have used a set of postcode centroids denoting places with
missing data to help target the mapping. More recently I have munged the
FHRS data by distributing all places sharing a postcode on a circle of
10-20 m radius and created GPX files for particular areas: with each FHRS
category having a different symbol.
A town the size of Melton Mowbray took around 90 minutes to do a photo
survey. Adding the data to OSM rather longer. Stockport, another, larger,
retail centre, which I have now surveyed in 2015 & 2016, took about 3 hours
altogether. Some of this was duplicated, and in part was because the
Merseyway Shopping Centre closed before I got round it on my first visit. A
second visit is useful because one inevitably notices anomalies which
require investigation when entering the data. My strategy is to take photos
and a limited number of notes or audio files, and therefore maximise
mapping time. This is all based on FHRS having all the other relevant data,
which doesn't work everywhere.
In summary using FHRS data enables a fairly targeted approach to mapping
town centres. It greatly helps in assembling address data in such places
and, of course, adds to the detail. For the mapper it's quite rewarding
because one can quickly see the impact. Although shops can change a lot,
having the much less ephemeral address data ensures this is not a Red Queen
('running to stay still') task.
Jerry
On 13 September 2016 at 09:25, Ed Loach <edloach at gmail.com> wrote:
> Paul commented on John's suggestion:
>
> > Speed limits would be a good one, although impossible to armchair-map
> unless you know
> > something I don't. Also, would it stem the tide of useless speed limit
> notes from Navmii GPS users?
>
> I can't guarantee it would stem the tide of Navmii speed limit notes, but
> I added lots of speed limits locally when Skobbler were creating MapDust
> notes and it seemed to stem that tide.
>
> I like Robert's fhrs suggestion - I keep meaning to cross check what is
> and isn't mapped against the fhrs list but haven’t got around to it. Making
> it a project might spur me to do so.
>
> Ed
>
>
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