Friday, 13 January 2012

Convenience stores and supermarkets

The standard classification system for different types of business uses the concept of "Retail sale in non‑specialised stores with food, beverages or tobacco predominating". This makes two important distinctions: between non-specialised, and specialised shops (Sainsbury's vs the local butchers); and between shops that are mainly concerned with food (Waitrose) and shops concerned with other stuff (John Lewis). It still covers a wide range of different types of business - from a hypermarket to a cinema kiosk (including village stores, NAAFI shops, confectioner / tobacconists, and old-fashioned grocers).

In this context, OSM contributors make widespread use of "supermarket" and "convenience store" to describe non-specialised food shops. There are a few tagged "kiosk", "general store" (in various spellings), or "grocer" (in various spellings) but these only amount to about 2% of the total in this area. There is only a smattering where different shop types are combined in forms such as "convenience;alcohol".

The retail experts, IGD, reckon that there are 91,500 stores selling groceries in the UK, of which almost 8,000 are supermarkets (or variants), and more than 48,000 are convenience stores. About 6,500 of the convenience stores are on forecourts. Most of these will probably be marked in OSM as a petrol station, rather than a shop. That leaves nearly 42,000 convenience stores that we should be able to find. However, this might still be over-stating things a bit. The Association of Convenience Stores reckons that there are 33,500 convenience shops in the UK.

Across Great Britain I can find 5,849 supermarkets in the OSM database, and 6,928 convenience stores. So on face value, current coverage of supermarkets is about 73% and coverage of convenience stores is about 16-20% (depending on what baseline we use).

Normally a convenience store is quite a small store, with extended opening hours, while a supermarket is larger, and opening hours are more tightly controlled. In the UK, shops smaller than 280 square metres (about 3,000 sq. ft.) have greater flexibility on Sunday trading hours.

Where a shop is added to OSM with a building outline we can get a rough idea of the floor space, and we can use 3,000 square feet as as way of distinguishing convenience stores and supermarkets. There's no point in being rigid about this, but in general a "supermarket" with a floor space of less than 3,000 square feet is probably a convenience store, and a "convenience store" with floor space of much more than 3,000 square feet is probably a supermarket.

Where I can measure them, the average floor space (actually building footprint) of a convenience store in the OSM database is 2,000 square feet, and the average floor space of a supermarket is 43,000 sq feet. Both are well inside the right range. However, about 4% of features tagged "supermarket" could be in the wrong category, and about 20% of features tagged "convenience store" could be in the wrong category (though most of these are still quite small). Re-allocating these according to size rather than tagging would take supermarket coverage up to almost 90%, and convenience store coverage down to around 14-17%.

The bottom line is that coverage of supermarkets looks pretty thorough - the majority are in the database, they can easily be identified, and tagging is pretty consistent. Coverage of convenience stores is better than for most types of shop, but could be more thorough. Many can easily be identified in the database, but some of those might better be tagged as "supermarket".

According to the Department for Transport, most of us are within 10 minutes of our nearest food store, and within reasonable travelling distance of 3 or 4. The chances are that at least one of these is in the OSM database, and at least one is still waiting to be added. The missing ones are likely to be some friendly local convenience store - not some massive supermarket chain. Which hardly seems fair.


Tom said...

I suspect some of the smaller "supermarkets" in our database are small Metro/Local/Express/Little etc. outlets of major supermarket chains.

gom1 said...

Good and interesting point Tom. I've done a quick check by name / operator. At first pass it looks as though the split among "convenience" chains (Londis, Spar, Costcutter) is about 80:20 in favour of "convenience". The split on "Tesco" is 90:10, and the split on "Tesco Express" is about 50:50. The image of a big chain might influence how small shops get tagged.

gom1 said...

A more careful check on how different operators are tagged: more than 90% of Londis, Premier, One-Stop, McColl and Mace stores are tagged as "convenience". Around 80% of Costcutter, Spar and Nisa are tagged as convenience.

The Co-op is about 40% convenience, 60% supermarket.

Budgens, Tesco, and M&S are 70-80% supermarket. Sainsbury is 90% supermarket. Iceland, Netto and Waitrose show only a few convenience stores, and everone else shows well over 90% supermarket.

I'm not sure how close that is to their actual store mix, but it doesn't feel as though it's far out to me.

kev said...

The day job gives me a bit of an insight on this, alas I can't provide hard numbers for you, but some broad percentages of the bigger chains might be handy...

Netto closed a few years ago - most stores ended up as part of Asda with a few becoming Morrisons and fewer still other retailers. Asda is 100% supermarket.

Tesco Metro is a bit of a funny one to tag - it's probably closer to a 1980s city centre supermarket than anything else - i.e. less non-food stuff and a slightly smaller range than the superstores on out of town retail parks but generally supermarket prices, although missing some promos. In Great Britain Tesco is about 65% convenience (the Expresses), 30% supermarket (i.e. Extra and plain old Tesco, with the rest being Metro's. (One Stop are also Tesco but run as a stand alone company).

Sainsbury's is about 50:50 Supermarket:Convenience.

Morrisons is just starting to roll out it's M Local convenience store concept so has only a handful of convenience stores currently. And watch out for the Morrisons Dry Cleaners and Morrisons Cafés when counting these. Waitrose is also quite new to the little Waitrose (i.e. convenience) concept so will have a smaller percentage than Tesco or Sainsbury's.

Moon Lit said...

Purchases are separated into goods and services. Then there are goods that cost more because of the additional service going towards the final product.
Let's take a look at four grocery delivery items that would fall into this category.
grocery convenience

Moon Lit said...

Ever found a searching list on the bottom or in associate empty cart at the store?
Peeking at someone's grocery searching list is unbelievably eye-opening. A printable or written grocery list is sort of a window into someone's life.

grocery convenience

Rosenrose said...

Purchases are separated into goods and services. Then there are goods that cost more because of the additional service going towards the final product.
Let's take a look at four grocery delivery items that would fall into this category.

grocery convenience