Zit Seng's Blog

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GPS Navigation Put to the Test


I had the opportunity to put to test Nokia Map’s GPS navigation last night, traveling to a destination (Kelantan Road) I had never been to before. I did check up streetdirectory.com to confirm it was a locality that I was indeed unfamiliar with. So I thought, why not let GPS navigation take me to my destination?

So, I set off from my home (Upper Bukit Timah vicinity) with Nokia Maps navigating me to my destination. It told me to get onto the PIE at Jalan Anak Bukit, head eastward, and to get off at Thomson Road. You know, the exit at the old Police Academy is a little tricky, because it also forks into a slip road to head toward Toa Payoh. The navigation instructions was clear enough to make sure that I took the left most fork to exit into Thomson Road.

From Thomson Road, I was eventually led to Rochor Road. Uh. I know Rochor Road. If I had come from Upper Bukit Timah, the best way (imho) to get to Rochor Road was to simply go down Bukit Timah Road. It is a straight road all the way down to Rochor! Traffic at 9pm is light.

Even if Bukit Timah Road or Dunearn Road were to be congested due to peak hour traffic, the likelihood is that the eastbound PIE would be equally congested. It is afterall a parallel road. But nevermind traffic conditions, because there is no information to feed into the navigation system. Perhaps Nokia Maps is simply configured to favour highways, no matter if the route using highway is more complicated.

So I eventually got to the Kelantan Road vicinity where the navigation got pretty tricky. “Turn Left, and then Turn Right”. Next, “Turn Right, and then Turn Left”. Next, “Turn Left, and then Turn Right and then Turn Right”. Wow. But a bummer after that: Nokia Maps told me to turn right into a 2-way road with a centre divider. (For benefit of non-Singaporean readers, we drive on the left side of the road. To turn right, you’ll need to cut across to the far side of the road, which you can’t if there is a centre divider across the junction.)  Oh well, I heard there were some changes to the roads there, so perhaps Nokia Maps wasn’t updated yet.

Except for the detour through the PIE, I got to my destination pretty quickly and easily.

Next, the journey back. Arrrgh… it was trying to lead me back to the PIE! I refused to make the right turn that would lead me to PIE. I asked for an alternative route, and good enough, this time it led me along Bukit Timah Road. It cleverly told me to keep right when there was a branch into a parallel side road that serves shops, condos and other developments along Bukit Timah Road (the parallel side road eventually joins back anyway).

Then, the navigation gave me a rather strange instruction for the Jalan Anak Bukit/Clementi Road/Bukit Timah Road junction. Look at the map. I am travelling westward on Bukit Timah road, heading into the junction. The navigation instruction was to “Turn slightly left”. Huh? I had three choices at the junction: Go straight continuing on Bukit Timah Road, turn left into Clementi, or turn right into Jalan Anak Bukit. What do you mean by “slightly left”? Left into Clementi would be a totally wrong direction! Oh dear, fortunately I knew how to get home. It is a right turn into Jalan Anak Bukit. Continuing straight on Bukit Timah Road would work too, but it’s not the best route.

Some instructional “glitches” I’ve noticed include a case of a junction with a left turn that has a new left turn lane which opens up prior to the junction. It seems to me that the navigation software thinks it is like a fork, because it tells me to “keep left” when I need to take that turn. It doesn’t say “turn left”. Hmm. Had I not been familiar with the road, I would have thought: Yes, keep left, but it didn’t say to take the left turn, so I would have continued straight on the main road!

What’s my verdict? No doubt GPS navigation is a very helpful aid. It will not replace human intelligence, but it will replace our need to actively refer to a street directory while driving.

I have a suggestion. I think it would be useful for the navigation instructions to mention road names where appropriate. Drivers can read road signs. Sometimes it is good to have additional cues to help us confirm that we are taking the correct turn, or that we’re on the correct road.

Imagine if you are on a road with many turns close together, and you need to take one of them. GPS signals are not 100% precise, or sometimes there are some location glitches (e.g. software reacted too slow, GPS signal blocked…). To tell us “After 250m, turn left”, well, how accurate is that 250m? Particularly if I am going quite fast? Am I supposed to look at my odometer? When the turn finally comes up, Nokia Maps would say “Next possibility, turn left”. But you know, if the navigation system is not 100% correct with my position, and the turns are all very close together, I could be making the wrong turn.

Then again, getting computers to pronounce our road names could produce hilarious results.

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