Tuesday, July 25, 2023

workin' the numbers

This is kind of nifty: I get to compare the results from my pedometer to those of MapMyWalk (the app's name is apparently written as one word). Let's start with the info I can pull from my pedometer first:


The above numbers seem to be the totals for the whole day up to the moment I took the screen shot. Before I started the long walk, I saw I had already walked 2030 steps, which took 21 minutes. Subtract those numbers from the above, and the slightly more accurate stats would be the following:

21366 - 2030 = 19336 steps

201 - 21 = 180 minutes

My activity-calorie count must therefore be slightly less than 1300. Maybe 1250.

I'm not sure what the above count is all about. Maybe it's the count for the long walk, but I've never seen the pedometer restart at 0 like that for an activity. Normally, it only restarts at midnight. That's one advantage of the MapMyWalk app: I could walk past midnight, and because the app has its own workout timer, I don't have to worry about doing any weird arithmetic like adding pre-midnight and post-midnight steps to get a single total.

Above, we have the added information of distance (10.23 miles, or 16.46 km) and total burned calories. The total calories come from the sum of my activity-calories and my basal metabolic rate. If we went by the CICO theory (calories in, calories out), I could eat nearly 3000 calories' worth of food and not gain any weight.

Now, let's take a look at what the MapMyWalk app has to offer. First, below, the map of my route, starting at the green dot and ending at the red dot. I walked from my office in Daechi-dong to the Tan-cheon, then from the Tan-cheon to the Han River, all the way out to the Jamshil Bridge and just past it before turning around. I walked a sightly different path homeward when I went from the Han to the Tan-cheon, as you'll see right at the confluence. My homeward route followed the Tan-cheon for a greater distance before I broke right, crossed over the freeway, and walked down Gaepo street to my apartment, located right next to Daecheong Station.

As you see in the screen shot below, the app originally defaulted to the Imperial system, so distances are in miles, and the app says I did 8.72. Note that the pedometer said I'd gone 10.23 miles (minus a fraction of a mile to account for the 2000-some steps before the long walk, so 9-point-something miles). As I've long suspected, it looks as though my pedometer has indeed been exaggerating my distances. Then again, I've used MapMyWalk only once, so I have no idea whether it's more accurate than the pedometer. For now, though, I think it is because I've been leery of my pedometer for years. MapMyWalk puts the workout time at almost exactly 180 minutes, and the step count is a bit stingy at 19067 steps. Still, there's very little difference between MapMyWalk's 19067 and my pedometer's 19336. I do trust my pedometer's step counts: I've tested it multiple times, and it's quite accurate. If MapMyWalk is off by such a small margin, I think it's fairly accurate, too.

As you also see below, MapMyWalk offers a "minutes per mile" pace as well. A pace of 20:35 puts me at slightly less than 3 miles per hour—about 2.92 mph, or 4.7 kph. When I've done my own speed calculations, I usually get right around that figure (assuming I'm walking robustly), so I think MapMyWalk is accurate on this score as well. Overall, the app is looking fairly trustworthy. Note that the activity-calories figure is rounded up to 1.3K, but also note that that figure is also pretty much where my pedometer put me, so I think these two apps are confirming each other. To measure caloric burn, you have to be honest about entering your height and weight. I entered my stats into MapMyWalk using the Imperial system, so I typed in 6'1.5" and 260 pounds. I must've typed in the metric equivalent of that, long ago, when I initially set up my pedometer.

Below, the only really new information is my start time: 7:48 p.m.

And in the screen shot that follows, new information includes my average speed (rounded to only a single decimal) and a more exact, unrounded activity-calorie count:

In the next pic below, I've figured out how to change everything over to the metric system since that seems to be what I've gotten used to after years of living in Korea (I still have trouble thinking in Celsius, though). So my suspicion was right: the total distance comes out to about 14 kilometers—and again, my pedometer cannot be trusted to measure distance: it said 16-ish. Note that the "minutes per mile" stat has changed to a "minutes per kilometer" stat. A flat 12 minutes per kilometer would be exactly 5 kilometers per hour—roughly the human average. Ever since my stroke, I've been a bit below average.

MapMyWalk isn't entirely accurate, though. I caught two brain farts that it made while plotting my route. Both occurred in roughly the same area, at the confluence of the Tan and Han. One was a weird jitter; the other was a strange little pirouette.

In the pic below, the circled area is labeled "A" for "anomaly":

In the closeup pic below, anomaly (1) is the weird jitter. I never zagged inland like that; MapMyWalk did this on its on, possibly adding a few meters' distance to my stats and throwing off their accuracy. Anomaly (2) looks as if I did a pirouette or some sort of tiny, tight loop, and again, I have no idea why the app plotted such a thing. Neither of these anomalies is big and bad enough for me to complain too much about an app whose free version I'm using. As long as the distances are accurate to within, say, a half kilometer, I'm not too worried about inaccuracies like these.

All in all, I appreciate the new and different types of stats that the MapMyWalk app can give me. I don't think the app is quite as accurate as it could be, but overall, it seems to do a better job of measuring distance than my pedometer does. The graphical representation of my walked route is also a nifty feature even if it still bugs me to have my routes recorded and possibly shared with strangers. The new app and my pedometer seem to be almost totally in sync regarding caloric expenditure, and the apps' respective step counters seem to be off only by a few percent. I see that the workout mode contains a "stairs" setting, which I might use the next time I climb my apartment's staircase.

On previous walks across the country, I've had some people comment that they'd like to see map renditions of the route walked on any given day. With MapMyWalk, I think I might finally be able to provide that—if people are okay with a zoomed-out map showing my entire route for the day, with very few labels and details visible (as above).

With this new app in hand, I'll have a bit more walk info to slap up on the blog. I might not do that for every single walk from now until the fall, but since I have to get used to the app, I'll definitely toss a few more screen shots out there.



4 comments:

John Mac said...

Overall, I've been satisfied with the MapMyWalk app, but I don't have much to compare it to. I've occasionally had those weird aberrations; no idea what causes that. Maybe aliens. It does sometimes occur if I take a rest break and don't pause the tracker.

If you want a map with more detail, there are options for doing so. After you have saved your hike, click on the map, and then open the settings wheel. You can pick a satellite or hybrid version of the map. The maps I post are the hybrid style.

Happy trails to you!

daeguowl said...

Now you need to give strava a whirl and aee how that stacks up. It's what I use for cycling but you can switch it to a ton of different sports incliding walking. The advantage of it is that it shows you your comparative times for the same short segments of a walk so you can see how whether you're improving or not

daeguowl said...

Also, I assume the aberrations occur when you switch from one cell tower to another.

Kevin Kim said...

Paul,

Those cell towers must be really close together.