Friday, 1 November 2013

mission impossible

Regular readers will already be aware that I have a low opinion of Google Maps, but that opinion has sunk even lower following investigations of the accuracy of the map for my local area, which I reproduce here with annotations:

Among the essential features of a map that are absent from Google’s maps is a legend, a small panel that explains the symbols used on the map. However, I didn’t mention this in Off the Map—it didn’t seem important, given that roads were almost the only symbols on the maps I was commenting on, and I would expect even the most incompetent map reader to recognize these symbols for what they represent.

Unfortunately, I notice that Google now has two symbols for roads, the original strip of white bounded by two grey lines, which varies in width according to the importance of the road in question, and a narrower pair of grey lines enclosing the same background colour as the rest of the map. It is an obvious assumption that these two types of road reflect relative importance, and that the second is probably some kind of track, while the first is a ‘proper’ road, as in the following two photographs:

These photos were taken from positions A and B on the above map, looking southwest along the river. I think it is obvious which is the road and which the track, but it is the second picture that shows what Google proclaims to be a track. The ‘road’ on the other side of the river certainly looks more like a track to me. However, what a casual onlooker won’t be aware of, and what Google probably isn’t aware of either, is that the road on the north bank of the river is gated off and is thus inaccessible to motor traffic.

I have assumed Google’s ignorance here, but this may not necessarily be the case. I was staggered to discover a few days ago that Google invites users to submit corrections to its maps, a kind of cartographic version of Wikipedia. It is possible that the road along the north bank of the river has been designated a track because someone tried to drive along it and found the way blocked by a locked gate. The track along the south bank is freely accessible, although it doesn’t lead anywhere useful that can’t be reached more easily by keeping to the main roads. And both are Drainage Services Department access roads with signs warning people to keep out! That includes pedestrians and cyclists.

I don’t have a lot of time for Wikipedia—as a former professional editor and proofreader I cringe at the obvious amateurishness of much of its editing—but at least it cites sources for its information, and it can call on subject experts to verify its statements. Allowing anyone to edit a map is a recipe for disaster, because nobody is checking on the ground, and there appear to be no controls in place to weed out inappropriate changes. Who, for example, thought that the bridge across the river at C carried a road? Does this look like a road?

While I’m on the subject, does this look like a road? The following photo was taken at E, looking west.

The entire network of ‘roads’ shown on the map southwest of D is actually a network of footpaths!

I come now to the most egregious piece of nonsense I’ve so far discovered on a Google map, although I do admit to a degree of mischievousness in setting Google the task of finding the easiest way to drive from Fu Tei Au Road to the village of Ho Sheung Heung. After all, I already know how to get from one to the other, at least by bike. The crossing point under the railway, featured recently in The Hill, is marked with a small o. Still, the directions provided are admirably succinct and straightforward.

There is just one tiny problem. You will note that the suggested route starts by crossing the railway, but there is no bridge over nor tunnel under the line. There is a level (grade) crossing at X, but the gates are permanently locked. I imagine that only the police and the military are allowed to make use of this crossing, which remains in the ‘closed area’. You would need a Caterpillar D9 bulldozer or a Sherman tank to get through here. And Tom Cruise won’t be able to help you either. But then, his films are fiction. You knew that, of course. Now you know that Google Maps are also fiction.

Crossing the line? Mission impossible!


  1. Much as I agree that Google Maps have issues, have you tried Apple Maps? I suggest a search for Alexandra House, Central, Hong Kong. Astonishingly poor, unusable.

    1. No I haven’t Tom (I assume that one needs an iPhone, which I don’t possess). However, it appears to me that Apple has done what I accused Google of doing in Off the Map: using commercially available satellite images without checking anything on the ground. Like Google, Apple probably doesn’t employ cartographers either.

  2. Around two years ago I purchased a GPS thingymajig (for driving) and for the life of me I cannot imagine how I ever managed without it

    1. Map or GPS, they are only as good as the data on which they are based, and relying uncritically on either could have disastrous consequences.

    2. Very true Dennis, it is all too easy to place blind faith in electronic gadgets without applying a little common sense. However the gadget I bought must have paid for itself considering the wasted petrol, time and stress when like me, one excels at getting lost

    3. I don’t get lost Keith. I may not know where I am at a given moment, but I always know how to get back to a known location. I wonder how a GPS unit would cope with the part of Hong Kong I’ve been exploring in the past year, because Google Maps is no help at all.


Please leave a comment if you have time, even if you disagree with the opinions expressed in this post, although you must expect a robust defence of those opinions if you choose to challenge them. Anonymous comments may not be accepted.