"Freeze Points" metric

[hozn]

I will get back to you on that. The criteria is based on ride start location and weather observations over the duration of the ride, but I am not sure what chart you are referring to, so I will check the data.

[eminva]

@hozn 134670 wrote:

Just to follow up, the rides are all using lat/lon-based weather now. So this is as good as it’s gonna get unless we can find a more accurate/better-coverage API for weather data.

Thanks! I moved way up on the coldest ride leaderboard (can’t remember where I was; now I’m #30). Still neither under- nor over- performing on Freeze Points — I blame it on those rides in Florida last month. :roll eyes:

Liz

[davidq]

@hozn 134677 wrote:

I will get back to you on that. The criteria is based on ride start location and weather observations over the duration of the ride, but I am not sure what chart you are referring to, so I will check the data.

I mean “individual various” > “coldest ride”, but now looks like it got correct.

[hozn]

@davidq 134676 wrote:

Wow, nice work hozn.

I have a question for the coldest ride, what’s the criteria? I check mine looks like it pick the ride on Feb 6 which marks 33.10F (average?), but I knew this is not true. I have many short ride under frozen temperature, but the one I won’t forget is the ride I did on Jan 18 (https://www.strava.com/activities/473181536) because my water bottle totally frozen and I didn’t get drink until rest stop. My phone AccuWeather show that I started at 14F and finished at 19F. I am pretty sure the whole DC area should has similar temperature on Jan 18, which is MLK Birthday.

Perhaps you were looking at this while the data was being reprocessed? Your coldest ride shows on the chart as 15.8F.

Indeed the ride you linked had an avg temperature of 18.14º and average windchill of 3.4º (maybe we should incorporate windchill into these metrics).

mysql> select ride_id, ride_temp_start, ride_temp_end, ride_temp_avg, ride_windchill_start, ride_windchill_end from ride_weather where ride_id = 473181536;
+———–+—————–+—————+—————+———————-+——————–+
| ride_id | ride_temp_start | ride_temp_end | ride_temp_avg | ride_windchill_start | ride_windchill_end |
+———–+—————–+—————+—————+———————-+——————–+
| 473181536 | 15.8 | 19.4 | 18.14 | 3.4 | 4.5 |
+———–+—————–+—————+—————+———————-+——————–+
1 row in set (0.00 sec)
[/CODE]

Note: the average temperature is calculated by sampling the observations (for *start* lat/lon) over the duration of the ride. (So it is not just (start_temp+end_temp)/2)

Attached is a shortened (to just a subset of AM observations) version of the weather file data that was used to calculate this in case you (or anyone else) wants to see the raw material here. The full files have observations for at least every hour, so are much larger (too large to upload, apparently).[CODE]
mysql> select ride_id, ride_temp_start, ride_temp_end, ride_temp_avg, ride_windchill_start, ride_windchill_end from ride_weather where ride_id = 473181536;
+

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| ride_id | ride_temp_start | ride_temp_end | ride_temp_avg | ride_windchill_start | ride_windchill_end |
+

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| 473181536 | 15.8 | 19.4 | 18.14 | 3.4 | 4.5 |
+

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---

+
1 row in set (0.00 sec)
[/CODE]

Note: the average temperature is calculated by sampling the observations (for *start* lat/lon) over the duration of the ride. (So it is not just (start_temp+end_temp)/2)

Attached is a shortened (to just a subset of AM observations) version of the weather file data that was used to calculate this in case you (or anyone else) wants to see the raw material here. The full files have observations for at least every hour, so are much larger (too large to upload, apparently).

[davidq]

hozn, you are amazing.

Any chance add team freezn points. I am not sure how vvil get his magic metric, but I am pretty sure that is against his/our team since most of our teammates Freezing Points ranking are lower than their individual point ranking.

[Steve O]

@hozn 134690 wrote:

(maybe we should incorporate windchill into these metrics)

No. Wind chill is mostly irrelevant to bike riding. On a calm day you generate your own wind chill anyway. A morning with 15mph winds from the west makes my wind chill differential 0 (it’s a tailwind, so I’m essentially riding in the calm) and hozn’s as though it’s a 30+mph wind. Like today, for instance. How do we account for that? Do we grant equal wind chill points to GB flying in with the wind at his back wearing a giant smile and hozn, battling against the wind for every inch with a frozen grimace?

We all already account for a 12-20mph wind when we prepare ourselves. Whatever wind is out there may add or subtract from that, but it probably evens out over time. It’s built in already, IMO.

[Steve O]

@hozn 134690 wrote:

mysql> select ride_id, ride_temp_start, ride_temp_end, ride_temp_avg, ride_windchill_start, ride_windchill_end from ride_weather where ride_id = 473181536;
+———–+—————–+—————+—————+———————-+——————–+
| ride_id | ride_temp_start | ride_temp_end | ride_temp_avg | ride_windchill_start | ride_windchill_end |
+———–+—————–+—————+—————+———————-+——————–+
| 473181536 | 15.8 | 19.4 | 18.14 | 3.4 | 4.5 |
+———–+—————–+—————+—————+———————-+——————–+
1 row in set (0.00 sec)
[/CODE]

@hozn 134675 wrote:

Wait, Ubuntu *is* a debian-based distro! 🙂 I use Xubuntu ..I like Debian’s stability, ..I have not tried this in dpkg land, but I assume you could not actually install Ubuntu packages that have been built against newer glibc (or other core Linux shared libs). You might also have to contend with different dep pkg naming, etc. At least that has been my experience mixing packages from different RH-based distros.

@jrenaut 134673 wrote:

I like Debian-based distros (and i’m currently running Debian 8 with Mate desktop) because they tend to be lighter than Ubuntu but can still use all the Ubuntu packages. .. go back to Crunchbang

@hozn 134670 wrote:

@jrenaut, this is just Ubuntu 15.10 / Unity desktop. I’m pretty impatient when it comes to distros these days and enjoy the huge ubuntu community

@Vicegrip 134671 wrote:

What magic is this? They are speaking in tongues. Burn them!

[ATTACH=CONFIG]10929[/ATTACH][CODE]
mysql> select ride_id, ride_temp_start, ride_temp_end, ride_temp_avg, ride_windchill_start, ride_windchill_end from ride_weather where ride_id = 473181536;
+

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+

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+

---

+

---

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| ride_id | ride_temp_start | ride_temp_end | ride_temp_avg | ride_windchill_start | ride_windchill_end |
+

---

+

---

+

---

+

---

+

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+

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| 473181536 | 15.8 | 19.4 | 18.14 | 3.4 | 4.5 |
+

---

+

---

+

---

+

---

+

---

+

---

+
1 row in set (0.00 sec)
[/CODE]
@hozn 134675 wrote:

Wait, Ubuntu *is* a debian-based distro! I use Xubuntu ..I like Debian’s stability, ..I have not tried this in dpkg land, but I assume you could not actually install Ubuntu packages that have been built against newer glibc (or other core Linux shared libs). You might also have to contend with different dep pkg naming, etc. At least that has been my experience mixing packages from different RH-based distros.

@jrenaut 134673 wrote:

I like Debian-based distros (and i’m currently running Debian 8 with Mate desktop) because they tend to be lighter than Ubuntu but can still use all the Ubuntu packages. .. go back to Crunchbang

@hozn 134670 wrote:

@jrenaut, this is just Ubuntu 15.10 / Unity desktop. I’m pretty impatient when it comes to distros these days and enjoy the huge ubuntu community

@Vicegrip 134671 wrote:

What magic is this? They are speaking in tongues. Burn them!

[ATTACH=CONFIG]10929[/ATTACH]

[jrenaut]

How do we account for thousands of torch-bearing citizens in our weather calculations?

[hozn]

@Steve O 134702 wrote:

No. Wind chill is mostly irrelevant to bike riding. On a calm day you generate your own wind chill anyway. A morning with 15mph winds from the west makes my wind chill differential 0 (it’s a tailwind, so I’m essentially riding in the calm) and hozn’s as though it’s a 30+mph wind. Like today, for instance. How do we account for that? Do we grant equal wind chill points to GB flying in with the wind at his back wearing a giant smile and hozn, battling against the wind for every inch with a frozen grimace?

We all already account for a 12-20mph wind when we prepare ourselves. Whatever wind is out there may add or subtract from that, but it probably evens out over time. It’s built in already, IMO.

Yeah, that’s fair. I was thinking we’d also track wind speed/direction and ride trajectory … but that is definitely getting more complicated. (And fetching windspeeds at various points along the ride would become a familiar problem of over-saturating API limitations.)

For my own use, I’ve thought of making a utility that updates my ride descriptions with windspeed and direction. This would let me normalize those variables to get closer to a question of answering the speed of different tires (e.g. take the Hunter Mill -> Vienna segment for days with different tires and same windspeeds and look at speed/power graph [or averages].) Have to think through that a bit more, but seems like it could work (or work well enough to provide meaningful data).

[ewilliams0305]

@Vicegrip 134644 wrote:

Looks fun but I would like to see better accuracy if it is used in the points system. The weather data used and my Garmin don’t even come close to agreement. I think where I start my 6 am ride is counted as DCA which is way warmer than where I start per the Garmin and the outdoor thermometer. I guess there is no way to use the Garmin data if it is present and default to the weather service if not.

Seems Hozn and I are right next to each other in the freeze points and we ride some of the same trail at a slight time shift.

I’ve also noticed this. For example When I road to WVA and Chambersburg and …… Stava reported my temp at 32 deg. I can assure you it was warm (32ish) at 4am when I left the city. By the time I was in WVA about 10am it was closer to 26, I know this because the university in shepherdstown has a big LED sign with the temperature displayed.

I’m sure it would be a royal pain in the frozen saddle to have the metrics include such a large geographic area on a single ride. I’m not sure if the weather underground API supports some kind of time/location GET. Neither am I sure if the strava ride parsing gives enough data to get the location of the rider at a given interval or time on the ride. If all this were or is possible, we could use the riders location at (1) hour intervals to grab a temperature every hour for the number of elapsed hours. Average then together and you’d have a very accurate way of determining the average temp.

Even on a 1-1 1/2 hour ride like what vicegrip is describing It would potentially decrease the overall temp of his ride as you’d have 2 temps to average.

All that said, how can I use all this data for my Longest coldest ride? I don’t think we’ve had any rides into the negatives yet so my current absolute zero is still zero.

[hozn]

@ewilliams0305 134731 wrote:

I’ve also noticed this. For example When I road to WVA and Chambersburg and …… Stava reported my temp at 32 deg. I can assure you it was warm (32ish) at 4am when I left the city. By the time I was in WVA about 10am it was closer to 26, I know this because the university in shepherdstown has a big LED sign with the temperature displayed.

Just to clarify here, temperatures reported by Strava are from your Garmin, not from any weather datasource. (Unless they’ve changed something.) — And these numbers almost certainly won’t match up with the avg temperature for rides that we calculate from wunderground observations.

@ewilliams0305 134731 wrote:

I’m sure it would be a royal pain in the frozen saddle to have the metrics include such a large geographic area on a single ride. I’m not sure if the weather underground API supports some kind of time/location GET. Neither am I sure if the strava ride parsing gives enough data to get the location of the rider at a given interval or time on the ride. If all this were or is possible, we could use the riders location at (1) hour intervals to grab a temperature every hour for the number of elapsed hours. Average then together and you’d have a very accurate way of determining the average temp.

We could absolutely do this. The wunderground API returns weather observations (for the entire day, usually in 1-hour increments) based on a latitude and longitude. And now that we’re storing full geographic streams for rides, we know exactly where you are at each of those hours during the ride. The “problem” here is that we have 265 riders and I’m limited to making 500 wunderground API requests per day. Hence we only request the weather for a single point per ride (start lat/lon).

@ewilliams0305 134731 wrote:

Even on a 1-1 1/2 hour ride like what vicegrip is describing It would potentially decrease the overall temp of his ride as you’d have 2 temps to average.

For rides <= 2 hours (which is 92.7% of rides in the database) we could just grab ride end point and use that for the second of the observation readings. This really only applies to commuters who log 2 rides for their commute (most) -- or other people that are ending their ride somewhere else. We might be able to squeeze that into the API rate limits if we make the assumption that we'd be fetching both start/end points anyway (i.e. start_geo is home in the AM and work in the PM, which means we've got a days worth of observations for both locations). Another thing we could do is decrease the fidelity of our lat/lon points — i.e. make them fuzzier — so that people that start out a couple blocks apart don’t require separate wunderground API calls. Essentially come up with some grid system that we think is fine-grained enough that weather stations will be the same anyway and then snap lookups to those coordinates. Then we’d probably have enough leftover requests to do multiple requests per ride and improve the data. … But I think any of that is going to require someone else to offer to do the legwork

[hozn]

@DrP 134672 wrote:

So, if you use manual entries for strava, none of these special metrics work? I guess trying to tell from my ride title where I went is tough in an automated manner. But they all are in the DC area, so one might think that could give some basic, even if not perfect numbers (and yes, DCA is all wrong with temp – there are many times through out the year that once you reach the Gravely Point parking lot you heat up until you cross 4MR. And one very memorable occasion of walls of temperature differences. And then the fog days.). Oh well. I guess I pay for not having something recording my every move. Darn.:rolleyes:

Correct, none of this works for manual rides. In fact, manual rides are excluded from many of the non-points leaderboards. Basically I got tired of people forgetting to enter a duration for their manual rides (distance 10, time 0 = infinite speed!) so any metric that has anything to do with time, speed, etc. excludes manual entries.

[Subby]

2nd overall and 23rd in freeze points. Ride smarter not harder.

[americancyclo]

@hozn 134733 wrote:

Just to clarify here, temperatures reported by Strava are from your Garmin, not from any weather datasource. (Unless they’ve changed something.) — And these numbers almost certainly won’t match up with the avg temperature for rides that we calculate from wunderground observations.

So does this mean that it pulls from the closest station and also pulls temp at the departure time?

Here’s a comparison of my data for this morning using my garmin, the Wunderground PWS that are closest to my start and end point, and DCA.

[TABLE=”width: 251″]
[TR]
[TD][/TD]
[TD]Garmin[/TD]
[TD]Wunderground[/TD]
[TD]DCA[/TD]
[/TR]
[TR]
[TD]depart[/TD]
[TD]23[/TD]
[TD]29.8[/TD]
[TD]32[/TD]
[/TR]
[TR]
[TD]arrive[/TD]
[TD]28[/TD]
[TD]30.7[/TD]
[TD]32

[/TD]
[/TR]
[/TABLE]

[hozn]

Yes, we can crossref those numbers with the numbers in the system after tonight’s run.

[Author]

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