mushroom mushroom!

Posted by: Ian on 22 November 2014

mushroom mushroom!


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Our old favourite breakfast spot shut a few months ago, so today we tried out the cafe that has replaced it.

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research for caekwars

Posted by: Ian on 20 November 2014

research for caekwars


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Oreo Cheesecake is a thing – who knew! Also, green tea frappe is pretty awesome!

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not a jellyfish

Posted by: Ian on 20 November 2014

not a jellyfish


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X-rays are cool, not everyday you get to see inside your own head.

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know your enemy: HRM anomalies

Posted by: Ian on 15 November 2014

One frequent complaint from people using heart rate monitors for their running and riding (but most often riding) is anomalous data. Typically in the early part of a ride you might see periods where your heart-rate is recorded much higher than it actually is, and the issue often disappears after a few miles.

To understand where the majority of these errors come from, it is a good idea to understand how an HRM works and what it is measuring. Before affordable optical sensors such as the Mio Alpha, a HRM consisted of an elasticated chest strap with two sensor areas and a small transmitter pod. The two sensor areas detect minute variations in electricity generated at each heartbeat, relay it to the pod which in turn processes the signal and transmits it to a watch or bike computer via a protocol such as ANT+ or BTLE.

Knowing how the system works puts us in a better position to understand what external factors might influence the data -it’s no longer a’black box’. In this case, the electrical readings picked up by a strap is very small and therefore susceptible to interference from other, stronger electrical fields. It also helps to have an idea of what numbers might be right – a four hour ride with an average of 182 bpm or 60bpm after you’ve blasted up a climb should ring alarm bells.

The man-made fabrics used in modern sportswear is very prone to generating static electricity through friction or flapping in the wind, especially in times of low humidity. Have you ever taken heard the crackle of static as you pull on or take off a jersey? These currents massively outweigh those created by your body, and effectively jam the sensors ability to pick up your heartbeat. These artefacts often disappear after a few minutes of riding as sweat helps mitigate the static, though on dry cold days you can be plagued with it all ride.

I’ve been using a three part approach to control bad heart-rate data, and I have to say it very effective. While I still get artefacts, they are very rare, and normally because I forgot something.

Gels

  1. Conductivity Gel – This improves the electrical circuit between your body and the sensor; the better the connection, the more signal and less noise will be delivered to the transmitter. This cleaner data is also easier to process with far less artefacts in the data stream. I picked up this 500ml off eBay for $18, and given how little I need to use, I’m expecting it to last a couple of years.
  2. Anti-static Spray – Available from fabric shops (and some supermarkets), a few sprays almost completely eradicates rogue static electricity from your jersey and undershirt. Bear in mind that on very low humidity winter days you might need more than other times of year1.
  3. Polar Strap – I’m not sure if this helps reduce bad data, but I have found it lasts much better than the Garmin versions, which I seemed to be replacing every 9 months or so. It should be noted though that Garmin consider them ‘consumables’, so they should be expected wear out2. The Polar model takes the Garmin pod without needing any modification and has worked great.

The combination above have worked very well for me over the last few years to minimise bad heart rate recordings. The outlay is probably less than $30 for a year or more worth of consumables.

  1. I have been known to dump a little water onto my jersey in the area of the strap too if I forget the spray.
  2. HRM Strap death is normally denoted by sections of flatline low or zero hear rate rather than spikes

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WYMTM

Posted by: Ian on 7 November 2014

WYMTM


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‘What You Missed This Morning’ is the subtle art of trolling your friends with a photo. ‘WYMTM’ stands for ‘if you’d gotten up early/ if you weren’t out drinking last night/ HTFU/ what if it rains on race day?’ and others.

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is it Bill Bailey?

Posted by: Ian on 29 October 2014

is it Bill Bailey?


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This is the fourth time I’ve seen Bill Bailey at the State Theatre (Tinselworm, Dandelion Mind, Qualmpeddlar and today, Limboland). Each time hilarious, intelligent and tonight; featured Miley Cirus in the Style of Kraftwerk.

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kinglake road crashes

Posted by: Ian on 25 October 2014

A couple of days ago (presumably on a slow news day), the Herald Sun ran an article stating that the Police were calling for a ban on cyclists using Heidelberg-Kinglake Road in Victoria ‘for their own safety’.

“It’s the most dangerous road to ride on”

“I would love to see a ban on cyclists going up that stretch of the road as my concern is for their safety.”

“A car might hit them and the car driver is going to be fine, but the cyclist is going to be badly hurt or pushed off the embankment.”

Sergeant Lindsay Dixon (Diamond Creek)


I was pretty sure that information on accidents would be available online, and since my day job is mapping, I thought I would see just how dangerous this section of road was.

Firstly I hit up data.vic.gov.au for crash statistics, and was lucky to find a data extract covering January 1st 2006 to June 30th 2013. A quick skim through the download showed it to be a collection of CSV files that were keyed to a unique ID for each accident – easy to join as needed using GIS. The biggest issue with displaying the crash locations was trying to work out the coordinate system so I could display it with some underlying roads. The coordinate tags are labelled amg_x and amg_y so I was looking at the various Australian Map Grid options, but none of those were close. Finally I came across a hint that I was looking for ‘Pseudo-AMG’ so that gave me some routes to search along.

Fortunately, Nyall Dawson had run into the same problem last year and posted the proj4 string which I could use to create a custom Coordinate Reference System in QGIS.


+proj=tmerc +lat_0=0 +lon_0=145 +k=1 +x_0=500000 +y_0=10000000 +ellps=WGS84 +towgs84=-117.808,-51.536,137.784,0.303,0.446,0.234,-0.29 +units=m +no_defs


If you have access to ArcGIS you can also create your own custom coordinate system using the following data:


Transverse Mercator
Origin: 0
Central Meridian: 145 E
Central Scale Fact: 1
Unit: Metre
False Easting: 500,000 m
False Northing: 10,000,000 m
Geodetic Datum: AGD66


Having a custom coordinate system really sucks in general; there is rarely any need for one. However, I can see the reason here: most, if not all the standard Australian systems have a boundary that goes right through the middle of Melbourne.

By comparison, the basemap was easy; I’d previously downloaded an OSM file covering all of Australia, so it was just case of clipping out with the bit that I wanted with the command line and styling it up. It comes in in WGS84 (Lat-Long) so its easy to manipulate.

Ian$ ogr2ogr -f "SQLite" -dsco SPATIALITE="YES" -spat 145.07034302 -37.71098578 145.48095703 -37.47921744 Kinglake_OSM.sqlite australia-latest.osm.pbf -progress


First up, we have the data for all non-bicycle accidents on Heidelberg-Kinglake Road between Kinglake and St Andrews.

MotorVehicles1

Injury Severity Count
Fatal 2
Serious 24
Minor 23
None 3
Total 52

Second, we have the data for all bicycle accidents over the same time period1.

Bikes1

Injury Severity Count
Fatal None
Serious 1
Minor 1
None 1
Total 3

The statistics from VicRoads show that on this section of road, the ratio of injurious motor vehicles accidents to that of cyclists is approximately 25:1, far from ‘the most dangerous road’ as claimed.

Following the devastating fires of 7th February 2009 (Black Saturday), cyclists were some of the first people coming back, buying coffee and helping support the community. A good cafe is something cyclists look for, willing to ride out of their way for a favourite pre or post ride coffee every week. A hoard of hungry riders make a good and welcoming cafe a lot of money before most people are even out of bed at the weekend while an unwelcoming one will soon fine itself ‘blacklisted’ by cyclists. A sudden ban on that road will immediately cut down on the number of riders in the area, and much less income for the cafes.

‘Ban cyclists for their own safety’ seems to have currently replaced the constant bleating for registration and insurance, but it is no less flawed and, as far as I’m concerned, a reasonable indication that nothing said by that person is worthy of consideration.

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storm front

Posted by: Ian on 13 October 2014

Just before heading out for this evening’s run, I remembered that the weather forecast had mentioned storms coming through, and since it had been sunny all day, they had to come sometime.

Fortunately, we have a Doppler radar covering Sydney, which is great for seeing what is on the way. Expecting a few storm-cells, I loaded the page and was confronted with a red and black snake stretching the height of the map, and with the animated frames, it was apparent that it was going to hit in the next 15 minutes.

Radar

Now there is running in the rain, and there is insanity, so I decided the only running was going to do was up onto the rooftop, then down again to get a tripod, then back to the roof again.

Stormfront 3

Stormfront 1

As I set up, I could see the last few planes scrambling to get in and out of Sydney Airport ahead of the storm. Fortunately the front came through so fast that delays for travellers shouldn’t have been too long.

iPhone + Gorilla Pod + GripTight Mount

An iPhone 6 with aGorilla Pod and Grip Mount makes a remarkably good setup for quick deployment. I was using it to hold the iPhone steady while I tried out the Hyperlapse app. I did add an umbrella till the storm got closer, when I got slightly uncomfortable being on the top of a tall building with rapidly approaching lightning.




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Added 2014-10-15

I have a Python script that I have been messing with that captures the data from a Bureau of Meteorology, processes it, and then graphs some of the values with a nod to XKCD. Sometime I want to develop it further with a wind rose as well.

StormWeather

This storm event is represented by the smaller of the rain spikes, for all the mess on the radar, the actually quantity of rain was rather small. You can see the sudden drop in air pressure that preceded the front.

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kurnell sun

Posted by: Ian on 10 October 2014

kurnell sun


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Feeling pretty tired today and didn’t fancy too many hills; the 80km round trip to Cape Solander has about 400m of climbing in total.

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noms

Posted by: Ian on 8 October 2014

noms


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White wine with red meat is probably a hanging offence, but it works for me. A very nice meal out at our local Mediterranean restaurant.

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post-ride protein

Posted by: Ian on 5 October 2014

post-ride protein


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Fresh rock oysters after a morning climbing the gorges north of Sydney.

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bubble man

Posted by: Ian on 27 September 2014




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The new iPhone camera is really good.

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