How accurate is geolocation detection via IP Address

June 23, 2009 1:40 AM

How accurate is geolocation detection via IP Address?

I work for a small business who is only based in select locations within my country. I want to use Google Adwords to target very specific areas on a Google map.

Adwords recommends me to target an area with a minimum of a 35km radius.

My question is, can IP addresses really target down to such a granular level like a 35km radius?

Is granularity an international standard, or does it depend on individual ISPs?

I just need to set my expectations correctly. Can anyone help please?

posted by friedbeef to technology (21 comments total)

I live in Australia, and loads of geolocation tricks place me in the US if I'm connecting from work.
posted by pompomtom at 1:53 AM on June 23

MaxMind provide some statistics on the accuracy of their GeoIP databases.
posted by Gomez_in_the_South at 2:06 AM on June 23

Geolocation databases typically pick me up as being in the UK (correct) but in Warrington (incorrect to the tune of ~320Km). The closest has been London, which is 100Km away.

I'm far from being an expert, but I think granularity depends on the ISP and, I assume, whether the end user has a static or dynamic IP.
posted by mooders at 2:09 AM on June 23

I'm in the UK, but for a spell, I was "located" in the Ukraine. Which made Multimap'ing somewhat interesting. With my new ISP, I'm "located" in the nearest large town.

I guess it depends on an ISP's database.
posted by Solomon at 2:10 AM on June 23

The short answer is "Not Very" - particularly if you are comparing with the sort of fix you would expect from a postcode or GPS. Quite often the choice may be in the wrong city or wrong continent. Sometimes the answer may not be too meaningful. For example metafilter is here - of you zoom in all the way on this map you will see a building which may be the ISP's server farm - but which is really where the ISP has decided to say it is.

One other answer to your question might be "accurate enough to help determine the default settings of a location-specific form when deployed to a global audience". I think this is what this type of geolocation is most often used for.
posted by rongorongo at 3:05 AM on June 23

Sorry. Hence:

My question is, can IP addresses really target down to such a granular level like a 35km radius?

Not with any reliability.
posted by rongorongo at 3:09 AM on June 23

It depends on (1) how well you can map an IP address to a connection and (2) how well you can map a connection to a location.

For example, where I am at the moment got on the internet fairly early and has a class B subnet registered in the institution's name, so geolocation on my current IP address has street-level accuracy. Oddly enough, despite knowing where I am with street level accuracy, the geolocation website I used gives geographical coordinates that are out by 4km.

On the other hand, from my home connection I get the same thing mooders and Solomon find; my ISP doesn't divide up dynamic IP addresses by city, so mostly I get geolocated to 'London', which is about 150km from where I am.

I've never had my country incorrectly detected.

I gather in America ISPs are more likely to divide up IP addresses by city, so you might get better accuracy over there.
posted by Mike1024 at 3:11 AM on June 23

I'll take a different tact to answer this, since I'm a PPC guy, but not qualified to answer how accurate the IP based location is.

In terms of how Adwords uses geotargeting to that super-granular level, it's not terribly accurate in my experience.

The route that may help you get around this is using place names in your key phrases.

For example, instead of bidding on "widget companies" within 35km of your business, try targeting your whole region/country/whatever, and bidding on "widget companies in Fakeville" and "Fakeville Widget companies," and whatever variations on those terms make sense for your business.

I find that works more effectively for two reasons. First, it does an end-run around the inaccurate geotargeting. Second, that technique allows you to pick up searchers from outside your target area who may be looking for businesses in your locale.
posted by generichuman at 3:20 AM on June 23

erm ... IP geolocation ... not even close to that accurate on a semi-consistent basis (or any basis)
posted by jannw at 4:09 AM on June 23

At work, Geolocation pretty much pinpoints my office.

At home, Geolocation puts me in either Sheffield or London (250km apart) depending on how my ISP has routed my connection.
posted by twine42 at 4:25 AM on June 23

Some of our connections in France show up as originating in England so IP not so smart by me.
posted by Billegible at 4:39 AM on June 23

geo-ip usually places me in the correct town, but I live in the suburbs of a major metro area. Maybe geolocation works better in the US than abroad?
posted by pwnguin at 4:44 AM on June 23

IP geolocation is fatally dependent on the way ISPs allocate IP addresses. For example, some cable or DSL ISPs might have a specific pool of IP addresses that is issued only to people in your part of town (not deliberately, but because all those people connect to the same network node). Other ISPs might allocate addresses out of one large pool for all of their customers everywhere. The majority are somewhere between these two extremes.

IP Geolocation, no matter where it gets its data from, CANNOT be more accurate than the granularity of the ISPs address allocation policy. Personally I would trust it to identify a country, but that's it. Even that can be dodgy - I worked for a company with web proxy servers in seven countries. None of them was the country where I was physically sitting at a desk.
posted by standbythree at 4:50 AM on June 23 [2 favorites]

My home DSL gives me an IP address including the local major airport code. I've seen this for other cities (atl, abq). But (for instance) .abq.qwest.com used to come from nearly all of New Mexico. So the precision will also depend on where you want to localize. If you're in Boston you can probably avoid showing your ad to Londoners but you might catch the occasional person in New Hampshire.
posted by fantabulous timewaster at 6:15 AM on June 23

It depends completely on your location, on where the relevant ISPs are incorporated, and on how large an area they serve. Large cities tend to be pretty good, elsewhere not so much.

If you've got such a small, specific area in mind, then I'd recommend just going out and testing out IP addresses from the popular ISPs to see if they're identified correctly.

(Bonus: a valid excuse for visiting sites with "Russian Brides in Wichita are Waiting for You!" banners)
posted by qxntpqbbbqxl at 7:16 AM on June 23

ISPs dont reveal where their lines terminate and most times IP allocation is associated with some corporate office and not near where their major routers and switches are, let alone the addresses of the clients.

My IP at home is often associated with a far away suburb which is the billing address of my ISP. 35km? Perhaps a bit more out there.

Personally, I trust doing a traceroute and deciphering the router addresses than any proprietary geolocation database.
posted by damn dirty ape at 7:16 AM on June 23

My question is, can IP addresses really target down to such a granular level like a 35km radius?

No. My computer (and this web browser) have "moved" 80 km since I sat down. (I am not in a vehicle of any sort.)

Skype has a free-calling-within-North-America plan. For a while, a major problem with it was that they didn't think anyone connecting from Verizon IP addresses was in the United States.

On the other hand, I've been places where you could figure out my street address with traceroute.
posted by oaf at 7:33 AM on June 23

I'm correctly located within a mile both at home on a standard residential connection and at work (office of 150 people).
posted by Brian Puccio at 7:42 AM on June 23

Geolocation by IP is only as good as the service that it is built upon. Google says they can pinpoint "within 200m accuracy ... in hundreds of cities around the world." That's for the API they made public for Google Gears. No idea how accurate their geolocation is for Adwords.

Oh, and geo-ip databases are not at the mercy of the ISPs. SkyHook uses GPS signals from iPhones to constantly "self-heal" their database.
posted by joe vrrr at 9:36 AM on June 23

From what I can tell, it really depends on a lot of factors relating to the registration of said IPs with ARIN and other agencies. For example, we use 3 different colocation facilities here in Vancouver for our servers. I've noticed that two of the three's IPs are shown as being in downtown Vancouver since that's where the colo head offices are, despite the one of the data centers being 20 km away in Burnaby. The third colo has head offices in the US, so their IP blocks show up as being in Virginia. Which is handy for me, since I can use one of our idle boxes as a proxy to watch hulu.com without getting hassled for being in Canada, but not so good for anyone wanting accurate geolocation.

Bottom line, geolocation relies on the quality of the data entered regarding the IPs, and all of that is done by humans at some point. It's not generated automatically by a technical routing system or anything of that nature, so Garbage In - Garbage Out definitely applies.
posted by barc0001 at 10:31 AM on June 23

> Oh, and geo-ip databases are not at the mercy of the ISPs. SkyHook uses GPS signals from iPhones to constantly "self-heal" their database.

They are *absolutely* at the mercy of ISPs. The IP address you have just been allocated may have been used ten minutes ago by someone in another state, depending on how your ISP allocates IP addresses.

Google's claim of 200m accuracy appears to be invalid. Here is the route between where I actually am, and where Google Gears thinks I am.

What SkyHook is doing is very clever, but it is emphatically not IP geolocation. They are using iPhones with GPS and wifi to figure out the geographic location of wifi networks. Then they are using the proximity of the wireless networks to figure out the geographic location of devices with wifi, but without GPS. This is a completely separate issue from IP geolocation, which is about figuring out where someone is based entirely on their public IP address.
posted by standbythree at 10:55 AM on June 23 [1 favorite]