Category Archives: English

Correcting splits

Last weekend, during the ROM 2013, a couple of SI-controls were out of sync. The overall times were correct, but for a few courses, the ones comprising controls 138, 148, and 163, the Splitsbrowser graphs looked awful.

I looked at the data sources (the line that looks like <PARAM NAME="src" VALUE=eventdata.php?eventId=6336>), and downloaded the file (after pasting the base-url in front of it.

Then, I inflated the file, which was compressed in gzip-format, using the 7-zip program, and looked at the contents.

I noticed that for some controls, the split-times were not monotonously increasing:

Jan-Gerard Van der T  [138:19]  87:11  02:03  03:21  07:39  09:49  12:20  18:23  20:31  21:25  23:23  28:46 139:29  34:23  37:28  40:09  43:54  46:19  -----  50:35  52:08  55:45  61:09  65:05 187:47  69:41  71:27  73:37  75:28  79:19  81:53  83:19  85:36  86:51  87:11

I found out that SI works a bit different than EMIT: the clock is in the control, and not in the badge, which means that the registered times may vary from control to control. It only works when all controls were synchronized, and that was not the case here.

But, no problem, I could correct the data file for that, if I would know the offset, how much the specific controls were off.

First, I looked at all the results, of all the different courses, and found in total three controls that consequently gave the wrong reading. Then, for the controls in my course, course 1, I looked at my GPS tracklogger data, and noted the difference in time between the wrong controls and the previous, or subsequent ones. I subtracted that difference from the time difference in the Splitsbrowser data files, and the result was the offset, for each of the controls.

This worked at least for 138 and 148. For 163, which was not in my course, and of which I therefore had no time information, I looked at the variation time difference between checking 163 and the previous, and the next control, and assumed that the ratio between the relative standard deviation of the leg time for the leg before and after it, would correspond to the ratio in distance, and thus in time. Thereby, I estimated what the offset would be.

Then, assuming an offset for all three controls, and with help of a couple of lines of Matlab code, I processed the data files, and uploaded them to my server.

So now, while the ROM’13 organization may upload the final results to the official site, you can enjoy a proper Splitsbrowser results page, on my own

STAGE 1, March 9th, Vrachelse heide.

STAGE 2, March 10th, ‘t Zand.

The original Splitsbrowser pages can be found here: Stage 1, and Stage 3.

By the way, it is interesting to observe the time-spread in split times, or asynchronicity of the SI-clocks, by comparing the GPS-log speeds at the controls, for both an SI-timed- and an EMIT-timed event:

left: SI: the controls are timed about +/-3 seconds accurate. right: EMIT shows obviously a better correlation.


New shoes!







I bought a new pair of shoes: the Inov-8 RocLite 285. For orienteering and for street-running. Not that the old ones were worn, but they didn’t fit all the terrains I use to cross.

Most orienteering races, I run my pair of Inov-8 Oroc 340’s (346.6 kilometers on the odometer, right now), that I bought April 1st 2012. But the steel spikes are not the best base on asphalt or other pavement.


On the other hand, the soft, flat, smooth sole of my marathon shoes, the Saucony Men ProGrid Triumph 8, are not the best option for off-road racing. So I needed something in between, suitable for paved roads, and anything else. With a lot of grip, but without feeling the individual studs when running on paved roads. With a low heel, but some damping; although I prefer little damping on the road for the direct feeling. A light shoe for long distances, but with some stability for my ankles.

Length web-browsing, review reading, running-mate consulting, and fitting, pointed in the direction of the Inov-8 RocLite series. Other options had been the TrailRoc 255 and the X-Talon 190. I tried them in the O-Crew “shop”, and decided that the size should be ½ bigger than my Oroc’s (although they were the same brand).

Next thing was to try them out in the field. The first meters on them ever became the first of 15000, during the Genneperparkenloop. The result was a pair of blisters, but hey, what do you expect if you try your new shoes on a fast 15k with sharp turns and some mud? The running itself went perfect, that day.

I was doubting whether to wear them during the Midwinterrun, and the Woudlopers Oriëntatierun. But I didn’t. Afraid to make the flashy red fabric dirty? No, I guess I just stuck to what I was used to, my good old Orocs. But last Friday, I ran the night orienteering run in Genk on them, to my complete satisfaction, and last Sunday, I ran, through the fresh snow, through the forests and over the hay around Leenderheide.

This last run was a good combination of paved and unpaved roads, fresh and compact snow, and loose sand and mud. On most terrain, the grip was perfect; only on hard, compacted, snow, I felt minimal sliding back, but no loss of control. I got the feeling there that the Orocs would have performed better there, but I did not compare them at that moment, under the same circumstances.

Furthermore, I noticed that the open structure of the upper shoe easily lets in water (melted snow), and I heard that the same would happen in dry sand. But I suppose my feet would have gotten wet anyway after running through 5 cm of fresh snow for 1.5 hours.

On the other hand, on the paved roads, back in the cite towards home, they behaved pretty well. The roads were wet, with slush-puppy substance on them, and the grip was excellent. The soles are a bit stiffer than my road-running shoes, but still comfortable enough to sustain for a longer period (and it is a good way to exercise the recoil in my calves).

So, my conclusion so far is that I made the right choice, to find a balance between on- and off-road shoes. And I guess that I will use them quite a lot for training, when I first have to conquer the asphalt, before I reach the wilderness. But for sprint-orienteering, they could be my favorite too. We’ll see. They’re a good excuse anyway to create some more elephant-trails

Overlay maps: the browser does it all!

I created something similar before, but I simplified the code a bit, and the result is still exciting. I put some JavaScrtipting in my weblog, to overlay maps with each other. The result you can see on this blog entry from a past training, when we had to draw our own map, and my latest post about the Midwinterrun, where I overlayed an ancient map we got with the current topographic map.

The fun is that you can change the opacity of the different layers. In the first example, you can change the view to the map of the different runners, with and without the real, complete orienteering map underneath, or with the map semi-transparent.

In the second example, you can hover with your mouse over a slider, that changed the opacity-ratio of the two different maps.

It is nice to see that some features in the landscape still remain visible, while others have completely gone. And it is remarkable that some features were apparenty not correctly mapped, one-and-a-half century ago, as they have not moved, for sure, in the mean time, but are shown on the map on a significantly deviating location. I tend to believe that the present map is correct.

The JavaScript code is shown below:
<p><a name="overlay"></a>nieuwe kaart <span id="slider"></span> → oude kaart<br />
(ga met je muis over het balkje om de kaart te wisselen)</p>
<div id="kaarten" style="position: relative;">
 <a href="">
  <img id="overlay_oud" style="position: absolute; left: 0pt;" alt="" src="" width="640" height="533" />
 <a href="">
  <img id="overlay_nieuw" alt="" src="" width="640" height="533" />
 <br />
 <script type='text/javascript'>
/* <![CDATA[ */
//gebruik geen lege regels want die worden als paragraph tag aangemerkt door de editor 
  var max=20;
  for (var i=0; i<=max; i++) { 
    jQuery("#slider").append("<span id='sliderstep"+i+"'>&equiv;</span>"); 
  jQuery("[id*=sliderstep]").hover(function () { 
  jQuery("#overlay_oud").fadeTo("slow", 1);
/* ]]&gt; */

I first create overlaying images, in the plain HTML code. With the style setting, I ensure they overlap. The images should all have the same pixel-size. Just above them, I placed a placeholder for the slider.

Then, I use a bit of JavaScript to create the actual slider, and the handles that change the opacity of the image layers.

Finally, I select which image is shown initially.

It’s all about speed

That’s great: at the bottom of this page, you can enter your own time and distance!

While running, I’m often wondering: while orienteering, it’s “which way?”, on the road, it’s “how fast?”. Like: “I am now running at a pace of 4’01”, I’m halfway my 1 km interval, how much fasther should I run to get to an average of 3’59” by the end of this interval, and how much does that differ on half a marathon?”. That type of questions.
[Dutch version]

Some time ago, I discussed (and calculated!) that you shouldn’t be thinking while running, at least not when you already know whereto and how fast, but that is even more a motivation to do that beforehand. And, while running, dig the answers from your memory. That’s the reason for this article.

Let’s start simple: for once and for all -and that will be this year- I want to finish the Half Marathon within the one-and-a-half. So, that is 21.098 kilometer in 90 minutes. Dividing those figures results in a speed of 14.06 km/h (or 8.74 mph). With some experience I gained, I got a feeling for that speed. But still, it’s better to comprehend when express it as 234 meter per minute. And it sounds quite fast when I say 3.91 m/s (meter per second), which is about twice what I’m tall.

Since I take part in Orienteering races, the pace started to make sense to me (and because my GPS watch tells me). And now I know what it means to run 416”/km (4 minutes and 16 seconds per kilometer, or 652”/mile). The distance between two 'hectometerpaaltjes' (100 m signs)...I get a feeling for it. And, because I know that I have to keep that pace on the Half Marathon, it’s my reference for everything. 4’00” /km sounds already very quick, but recently, while training intervals with some colleagues, we incited each other easily to below 03’50” /km, and even with a sprint at the end, of 03’40” /km. Yet again, it’s easier to survey 100 meter than 1 km, especially when you want to estimate a distance on the road (the same as between the two ‘hectometerpaaltjes’). And, for my desired pace, I need to accomplish those 100 m within 25.60 seconds.

In my case, per 100 m, that is about double paces, representing 1.29 2pace/second, or 77 2pace per minute. In the past, I have looked into the relation between speed and heart-rate, (see my article Linschoten Loop on my blog), but I assume that that changes with time, with your training history, and with the terrain. And there is no space for that discussion here.

But what occupies me most, on my way, are the relative differences: how much faster should I run per 100 meter to finish one minute quicker? And, while running, I am typically not fit enough to realize that one minute contains about 60 seconds, so for each individual kilometer of the 21, that is let’s say 3. Or 0.3 seconds per 100 meter. That’s nothing! If that’s all for a finish time that’s one minute better, give me 10!

Below, a table, to observe the trends:

time speed pace difference
hh:mm km/h m/min m/s min/km s/hm % s/km s/hm pas/s pas/min
01:20 15.82 264 4.39 00:03:47.54 22.75 1.45 87.02
01:25 14.89 248 4.14 00:04:01.76 24.18 1.18 2.84 0.28 1.36 81.90
01:26 14.72 245 4.09 00:04:04.61 24.46 1.17 2.84 0.28 1.35 80.95
01:27 14.55 242 4.04 00:04:07.45 24.75 1.16 2.84 0.28 1.33 80.02
01:28 14.38 240 4.00 00:04:10.30 25.03 1.14 2.84 0.28 1.32 79.11
01:29 14.22 237 3.95 00:04:13.14 25.31 1.13 2.84 0.28 1.30 78.22
01:30 14.06 234 3.91 00:04:15.98 25.60 1.12 2.84 0.28 1.29 77.35
01:31 13.91 232 3.86 00:04:18.83 25.88 1.10 2.84 0.28 1.27 76.50
01:32 13.76 229 3.82 00:04:21.67 26.17 1.09 2.84 0.28 1.26 75.67
01:33 13.61 227 3.78 00:04:24.52 26.45 1.08 2.84 0.28 1.25 74.85
01:34 13.46 224 3.74 00:04:27.36 26.74 1.07 2.84 0.28 1.23 74.06
01:35 13.32 222 3.70 00:04:30.21 27.02 1.06 2.84 0.28 1.22 73.28

You may have noticed that for every minute you subtract from your projected finish time, the required increase in speed, per minute, becomes larger. Not only the speed itself –that’s obvious– but the speed difference too. Meanwhile, the difference in pace is always the same. The relative difference, in %, of the time per 100 m changes, but the absolute difference, in s per 100 m, stays the same. It’s all logical, but it may be practical to remember while you’re on the go: time over distance (pace) is linear as a function of the finish-time; speed, and relative changes in pace, are inversely proportional.

When you run the first half 1″ per km slower than the 416”/km you should run, you will have to catch up those 21.098/2 s during the second half. To do that, you will have exactly half of the total 21098 m available. So you have to run exactly 1″ faster per km, than the overall average. The net difference is 2″/km with respect to you pace in the first half. Sounds easy.

For 1:30:00, you will have to run precisely 4’15.98”/km. Your GPS is not that accurate, but fortunately it’s close to 4’16”/km. However, you will just miss your target time by 19 ms. That is 19 milliseconds –not much, but all your hairs grow about one atom in that time, still at total of about 1/100 of a mm altogether. You miss your target by 7.1 cm! But, if you would have run 4’15”/km (the difference is hardly visible on your GPS watch), that will gain you advantage of 21 s at the end. Just a matter of approximation. Again, this a figure that is easily remembered: for every 1 second you run faster than planned, on a distance of 21.098 km, you gain in the end as many seconds as there are kilometers. For every distance!

If your run a a bit slower, and have to cache up at the end, then it may be interesting to express that lag in meters. Just as if, at that moment, you pick another runner -who keeps running at a constant pace- that many meters in front of yourself, and strive to overtake him right at the finish. Suppose, you ran 1 second to slow per kilometer. Then, at the end, you have to catch up that 21.098 s lag, what, right at the end (which is in fact too late) boils down to 82 meter. This way, it sounds quite tough. And, when you find out 1 km before the finish, that all the time you aimed at a pace 01:31:00, one minute too slow, then you have to overtake, in that last km, someone who, at that moment, is 223 meter in front of you. No, you’re not going to make that.

There are a few things to remember: Suppose you’re in terrific shape, and it goes very smooth. You can keep a pace of 4’00” /km, then you will finish at 01:24:23 Fantastic! To get a feeling for those finish times, I have written them on a dial: thinking in time like an old-fashioned clock is -for me at least- still the most intuitive representation. On top of the dial it says 4’00”, and ever second/km more counts clockwise. Can you print this one on your retina?

The moral of the story? Just run just below the 4’16” /km, and you need not think about anything. That saves a lot of energy!

But the best about this page is maybe that you can change all the numbers to your own pace! Just enter here, km, the distance your are about to run, and here, , your planned finish time. And see what happens with all the figures on this page…

My 1st 1st in the 1st!

For the first time, I was first, and, above all, in course 1. With temperatures of 32 °C, knocking out half of the runners, and quite a dense forest, it wasn’t easy either. Half of the time, I couldn’t see the woods through the forest (“door de bomen het bos niet meer zien”, in Dutch), and not only because of my frosted cornea, due to the damp atmosphere.

I guess I am good when it gets tough. Since it was not because I made less mistakes. In fact, when I finished, I was quite dissatisfied with my result (which I could not yet compare with the others’). Quite a few controls, I ran together with Albert Jan Kuiper, while he nor me could shake the other off. And he spotted some controls before I did, so my first impression was that I had not ran my own race. Until he decided it was too heavy, and dropped back.

On the other hand, I did not make big mistakes. The course I took between the controls was almost the same I would choose now, but most problems occurred while searching for the flag itself. To some extend, I had expected this already, since I know that baanlegger Peter is a master in using the terrain to disguise the controls. But the difficult aspect is his eye for elevation contours, that is somewhat different than mine. Often, on the map, it is clear what should be the attack point, but at the location itself, I just don’t recognize all of the elevation features, especially right in the middle of the forest. And, which is typical for this season, open spots between the trees, may not be recognizable at all.

This was the first control where I overestimated myself. There was a much safer route from 12 to 13, but I took the risk.

But then, after a few controls of learning, I should be wiser, and know that I should take less risks, choose safer approaches, and orienteer by the book. Clearly, the breath of the competition down my neck makes quite a difference on the rationality of my route-planning cortex. Or my risk-estimating sub-consciousness.




What a chaos! Looks more like Map Doodling than orienteering.

Nevertheless, who can complain when he becomes first? Not me. I am happy and content after all!

oO-games (online-Orienteering)

I planned to add some home-made JavaScript Orienteering games to my blog. Sounds fun to make, and to play. Something with maps, where you have to find the location of a tiny snapshot of the map. And a puzzel, where you have to select the control description icons for a certain spot on the map. And a map where you have to draw what you think is the best route, and afterwards, get a simulated time based on the underlying map colors. Or a jigsaw puzzle of a map. Like this:

But first, I decided to look what is already out there. I have bought once Catching Features, which is sort of the complete orienteering experience on your PC. A lot of fun when you can’t go out for some reason. It pretty well resembles the stress when orienteering for real. But here appear to be many more tools.
I wish I had an Android smartphone, then I could play Virtual Orienteering, or pCM Orienteering.

But there are other Orienteering computer games as well. Have a look for example at:

  • Webroute: Here you can draw what you think is the best route, on a map, and compare with others. Seems to be used a lot, but not by many Dutch people.
  • Control Descriptions Quiz, where you can exercise your knowledge on control symbols.
  • Map reading Quiz, where you can rehearse with map features.
  • On ARDF-games, you can play with virtual ARDF receivers, a kind of orienteering where you use radio waves to locate the controls.
  • This one is also fun: you have to watch the head-camera video, and locate where you are on the map. Sounds like a fun idea for a Geocache.
  • Memory training: this one shows you a map for some seconds, and then you have to run the same route, along many crossings, to get to the end point, by what you remember of the map.
  • And if you like to play online puzzels, with Orienteering as theme, then this section of the Hamok Orienteering Handbook could be interesting.

But of course, the real game is outside. I found some good sites with training exercises, some of which you can do on your own when there is no nearby race, or no training. For example here, on, or this huge list, also from the Hamok Handbook.

Although there are not many regional races nearby during the summer season, there seems to be enough to do. So let’s quit writing my blog, and start playing.

More links:


Bloggen in Nederlands of Engels, that’s the question…

Ik vraag me af of ik deze blog niet in het Engels moet schrijven. I wonder whether I should write this blog in English or in Dutch. Orienteering is an international sport, and the North is everywhere (roughly) the same. Orienteering is een internationale sport, mijn publiek is uiteraard groter als ik in het Engels schrijf. I have a bigger audience when I writing in English. Aan de andere kant, het leest voor Nederlanders en Belgen wel weer lekkerder als ik het in het Nederlands houd. On the other hand, for the Swedish, it would be better if I would not write in Swedish, since that wouldn’t be readable at all (given my Ikea-only vocabulary). De vraag is dus: wie is mijn publiek or who is my audience?

Wie is mijn publiek?

En omdat ik ook een deel voor mezelf schrijf, gewoon om mijn gedachten op papier te zetten, denk ik dat ik het bij Nederlands houd. However, the bigger the audience, the bigger the motivation to write.
Mee eens? Of niet? Laat dan een berichtje achter onderaan deze pagina. Want ik wil best voortaan Engels typen.
De Google Ads heb ik weer van mijn site gegooid: niemand klikte ze aan, en het werd er niet overzichtelijker op. Leuk om eens te proberen, maar je moet wel heel veel bezoekers trekken wil dat wat opleveren. Wel kreeg ik meer hits om mijn blog-site zo lang ik Google betaalde (50 euro gratis introductie krediet) voor het plaatsen van links op andere sites.

Routegadget : Boshoverheide/Sylvester 2011

The issue with the database has been resolved. You can now upload your GPS tracks, or draw your route on the map manually. If you have questions, send me an email: jg.2011 at

Pictures of the event can be found on

This page is in English, for all the foreign competitors. Sorry, but I don’t speak all the other languages that have subscribed for this event.


With Routegadget, you can view the actual routes on a map. The different courses are pre-loaded, and the results, the Splits, are pre-loaded. You can make the different runners actually run on the map, with there respective pace on each leg.

But even better, you can edit your own route. That is the main advantage. We get the most out of it when more and more people enter their route. You can show your brilliant path-finding to others, and learn from the route decissions of the best runners.

There are two ways to enter a route:

  • By oploading a GPS track (GPS watches are not always allowed, but non-interactive GPS-trackes without a screen can be used in general). This particular Routegadget map has been georeferenced which means that your GPS data will fall right on place. Very easy.
  • By entering it manually with you mouse. Draw a line by clicking on the points you passed, and that is it.

The routes are directly visible to others. I have even prepared a laptop to allow entering your breadcrumb-track during the event (after the last participant has started).

After 13:30, at December 29th 2011, the site will be enabled. THIS IS THE LINK TO THEM MAP .

Pay attention: Wait until the map has fully loaded until you click on anything, otherwise Java might crash. And starting RouteGadget or SplitsBrowser twice can cause problems as well.

To view the maps, you need Java. Quite often, this has been installed in your browser already, but otherwise you can download it here. Then, after you clicked the link to RouteGadget, the map will be loaded. You can select the desired language on the top-right of the screen.

  1. Wait until the map has become visible.
  2. Select one or more competitors.
    1. Therefore, click on the popup underneath Choose competitors.
    2. Select a course from the list. The controls of the course will be plotted on the map.
    3. The names of the competitors will be shown underneath the selected course. The order of the names may be random.
    4. Select competitors by clicking on them, one at a time. You can use the button Deselect all on the bottom of the screen to clear your selection.
  3. Then click, on the bottom of the screen, on View routes. Now, the routes of the runners are shown, when the selected competitors have entered them but GPS-upload or manual drawing.
  4. With the + and – buttons, you can zoom in and out of the map. (Smooth scaling indicates the method Java uses to render the zoomed map, sharper or less sharp.) With your right mouse button, you can drag the map.
  5. You can start an animation with the selected runners. First, select the course, then the competitors, like described above, then FIRST click View routes and THEN View animation. Then animations starts when you press Start (bottom right of the screen). You can stop it, and make it go faster or slower. Note that you have to drag the map to the start position to see the animation, when the first control is not yet visible on your screen.


Upload a GPS track by clicking on “GPS” in the top right of the screen. Then select the file format to upload. You must first have downloaded the data from your GPS. (If you have trouble getting the data from your GPS, send me an email, maybe I can help you.) The track you upload should only contain the race. That means that you will have to edit the track in your favourite software (e.g. Mapsource, TrainingCenter, Basecamp, etc) to cut off the points before and after the actual race.

Then select the file (use Browse to browse your local storage), and click OK. In principle, the map has been georeferenced, you your track should be fitting immediately. Otherwise, drag the three blue handles until your track matches the map.

Follow the instructions after the upload. Select course and competitor name. When done, click the link to return to the map. Now, your track should be visble, among the others.

Draw your route

If you don’t have a GPS track, you can manually draw your route. This works quite easy. Click on Draw your route, select your course and your name, and start drawing. The straight-line course is already shown in magenta.

  • Drag the map to the start location.
  • The first leg is highlighted in blue. Your track is in red, but now, it is still only a dot.
  • Point on the location you moved to after the start. Click on the map. Now, the actual track is shown in red, and a blue line indicates the direction to the next control.
  • Continue until you reach the first control. Now the next leg is highlighted in blue.
  • Just continue those steps. Remember to drag the map with the right mouse button.
  • If you made a mistake, you can take steps back, by clicking the Undo button on the top right of the screen, next to Draw your route.
  • When you have reached the finish, click on Save route, and follow the further instructions.

When done, click the link to return to the map. Now, your track should be visble, among the others.

That is it. Now enjoy the results, as more competitors draw their trails, and analyse the differences in speed, to learn for a next race.