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How does Strava know the incline grade pct. of various roads?

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How does Strava know the incline grade pct. of various roads?

Old 07-24-22, 11:34 AM
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CheGiantForLife
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How does Strava know the incline grade pct. of various roads?

Is this some public GIS based topographic geo database they overlay your GPS location over?

Last edited by CheGiantForLife; 07-24-22 at 11:44 AM.
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Old 07-24-22, 11:39 AM
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I used to think it was done by known elevations at certain geographic points. But I think it more likely it is done by smoke and mirrors.
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Old 07-24-22, 12:18 PM
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Thinking the secret ban has expired.
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Old 07-24-22, 12:48 PM
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Old 07-24-22, 12:51 PM
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Old 07-24-22, 12:54 PM
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Originally Posted by CheGiantForLife View Post
Is this some public GIS based topographic geo database they overlay your GPS location over?
I read that 3 times and now I have to take 3 ibuprofen.
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Old 07-24-22, 12:54 PM
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Originally Posted by CheGiantForLife View Post
Is this some public GIS based topographic geo database they overlay your GPS location over?

They use data from the chips implanted in house cats.
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Old 07-24-22, 04:21 PM
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Originally Posted by CheGiantForLife View Post
Is this some public GIS based topographic geo database they overlay your GPS location over?
They use a mix of sources, including public topo datasets.

https://support.strava.com/hc/en-us/...-Your-Activity
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Old 07-24-22, 07:22 PM
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Originally Posted by livedarklions View Post
They use data from the chips implanted in house cats.
If the cat gets outside and climbs a tree the reading will be way off !
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Old 07-24-22, 08:42 PM
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Strava doesn’t know. The GPS (receiver and software in your phone) resolves your elevation. The Strava app uses that GPS data and applies it to the various aspects of the app. GPS can resolve your vertical position the same way it resolves your horizontal position. It uses timing signals between the GPS satellites and your GPS receiver device down to the nanosecond (One nanosecond is to one second as one second is to 31.71 years.). When you go up or down a hill, that timing signal gets longer or shorter. When it detects that, it goes one step further and does the math to determine the degree of inclination, or percent grade.

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Old 07-24-22, 08:45 PM
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Originally Posted by _ForceD_ View Post
Strava doesn’t know. The GPS (receiver and software in your phone) resolves your elevation. The Strava app uses that GPS data and applies it to the various aspects of the app. GPS can resolve your vertical position the same way it resolves your horizontal position. It uses timing signals between the GPS satellites and your GPS receiver device down to the nanosecond (One nanosecond is to one second as one second is to 31.71 years.). When you go up or down a hill, that timing signal gets longer or shorter. When it detects that, it goes one step further and does the math to determine the degree of inclination, or percent grade.

Dan
actually, strava doesn’t use GPS elevation if it can be avoided given how very inaccurate it is. if you read the link above you’ll see they first use barometric altimeter data, and if you “correct” it they use an elevation basemap which was made from that same data, crowdsourced, and then they fall back to public elevation maps/models. if the GPS position is off of course the elevation correlation will be off too.
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Old 07-25-22, 06:21 AM
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I can't fathom there is topo data that is so granular that some agency or entity actually recorded incline of every neighborhood street in USA
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Old 07-25-22, 06:22 AM
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Originally Posted by _ForceD_ View Post
Strava doesn’t know. The GPS (receiver and software in your phone) resolves your elevation. The Strava app uses that GPS data and applies it to the various aspects of the app. GPS can resolve your vertical position the same way it resolves your horizontal position. It uses timing signals between the GPS satellites and your GPS receiver device down to the nanosecond (One nanosecond is to one second as one second is to 31.71 years.). When you go up or down a hill, that timing signal gets longer or shorter. When it detects that, it goes one step further and does the math to determine the degree of inclination, or percent grade.

Dan
If this is the case, there must be simple altimeter apps out there.
I am going to test out this feature of the phone on my next walk
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Old 07-25-22, 08:00 AM
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Originally Posted by chegiantforlife View Post
if this is the case, there must be simple altimeter apps out there.
I am going to test out this feature of the phone on my next walk release.
ftfy
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Old 07-25-22, 08:20 AM
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Originally Posted by CheGiantForLife View Post
I can't fathom there is topo data that is so granular that some agency or entity actually recorded incline of every neighborhood street in USA
That’s exactly what Google Maps began creating back in the early 2000s. Apparently Strava now has their own database of elevations that you and I helped create.

Most of your answers about Strava-provided elevation can be answered at this link: https://support.strava.com/hc/en-us/...-Your-Activity

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Old 07-25-22, 09:35 AM
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Originally Posted by CheGiantForLife View Post
I can't fathom there is topo data that is so granular that some agency or entity actually recorded incline of every neighborhood street in USA
It may well be that you can't fathom it. That doesn't mean it isn't real. If you work with RideWithGPS to map and record routes, they have all that elevation data built in. They use Google Maps and OpenStreetMap as two of the choices in their map data, but their elevation profiles come from Google Maps, which shows the elevation changes in detail. That data is there before you ever get on the bike, so no need for either barometer or GPS input. It's one thing to ask questions because you don't know or don't understand, but it's another to be wrong and yet be sure you are right.
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Old 07-25-22, 09:54 AM
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Originally Posted by CheGiantForLife View Post
I can't fathom there is topo data that is so granular that some agency or entity actually recorded incline of every neighborhood street in USA
https://www.usgs.gov/faqs/what-types...can-i-download

there are several sources for this data, but the one i’ve most commonly used is the national elevation dataset, which is free. it covers (at varying resolutions) the entire surface of the country. all you need is that and the coordinates of two points on a road to determine the slope between them.

google uses this data (as well as many other similar datasets) for maps/earth/earth engine etc.
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Old 07-25-22, 10:39 AM
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I should have kept my original Strava record from the Five Boro Bike tour, it showed a vertical, 100% grade, 1200 foot change in elevation in lower Manhattan.

I used Strava's fix tool to remove the levitation. Strava got the original data from my GPS bike computer, so the GPS signal probably was bouncing off the buildings.
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Old 07-25-22, 11:13 AM
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Originally Posted by KerryIrons View Post
It may well be that you can't fathom it. That doesn't mean it isn't real. If you work with RideWithGPS to map and record routes, they have all that elevation data built in. They use Google Maps and OpenStreetMap as two of the choices in their map data, but their elevation profiles come from Google Maps, which shows the elevation changes in detail. That data is there before you ever get on the bike, so no need for either barometer or GPS input. It's one thing to ask questions because you don't know or don't understand, but it's another to be wrong and yet be sure you are right.
How did Google Maps create the topo data? Were there altimeters in the car? That is very cool.
I was in a private parking lot today, and Strava knew the % grade. No way that is in public topo data, but it has been driven by Google Maps!
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Old 07-25-22, 11:38 AM
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Originally Posted by CheGiantForLife View Post
How did Google Maps create the topo data? Were there altimeters in the car? That is very cool.
I was in a private parking lot today, and Strava knew the % grade. No way that is in public topo data, but it has been driven by Google Maps!
the public (USGS) data comes from satellite and aerial measurements. it includes the entire surface of the earth, including private parking lots.
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Old 07-27-22, 09:18 AM
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Originally Posted by CheGiantForLife View Post
No way that is in public topo data, but it has been driven by Google Maps!
Why are you always so sure about things that you don't know and are obviously wrong?
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Old 07-27-22, 09:33 AM
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Originally Posted by KerryIrons View Post
Why are you always so sure about things that you don't know and are obviously wrong?
especially funny when the link by which one can download said data, for free, is just a few posts above LOL.
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