So, your Garmin is most accurate for Strava hey?

[Long Wheel Base]

Many of us has flown before. Some landings are tougher than others. What makes these landings difficult, is the position of the pilot in relation to his landing gear. He needs to judge his height visually and he needs to keep one eye trained to the elevation so he can make an educated estimate on when it is time to feather the approach, making your live as a passenger as comfortable as possible. Pilots take pride in their jobs and good landings are amongst the items important for them (at least the ones I know). If the pilot has to rely on a barometric pressure sensor calibrated for zero in Durban, how is he going to get usable information on his approach to OR Tambo at a elevated 1685m.

True, That's why a commercial airline pilot flies IFR and they use a standard barometric setting for all airfields. Flying VFR is a different story though, On a VFR flight you are constantly getting the airfield weather(wind, Vis, pressure, active runway and so on) from the tower and re setting your altimeter. But the GPS used on the commercial jets is seriously accurate, when doing an auto land the GPS is synced with the ILS at the airfield and it lands that Aircraft with pin point accuracy. so much so that some airports are having to take measures on the runways due to the planes landing on the exact same spot every time and "wearing" out one spot runway.

[L'Bie]

for those interested in a bryton's view on life

 

It is after all just a Korean Garmin

[Pure Savage]

Never thought I would learn this much on a Tuesday morning on the hub!

 

*spelling*

Edited July 22, 2014 by skistar15

[Stretch]

It is after all just a Korean Garmin

 

that might be the case...but it certainly looks more accurate than the garmin

[fandacious]

theoretically you could get an approximation of altitude via topography + GPS position.

 

Do you have any idea how much space you would need on the garmin to store all that topo info?

 

And then to top it off, its not even really very accurate, so your elevation will be way off at end of the ride.

 

Just reset your barometer once a week and it should solve most of the issues

[Long Wheel Base]

Never thought I would learn this much on a Tuesday morning on the hub!

 

*spelling*

This has been going on since yesterday, If we not careful we'll be made to write an exam at the end of the lesson.

[Stretch]

you must also bear in mind that the projection issues between geographic coordinates from the GPS and the google projection (which is a custom projection based upon lambert confromal conic) used in google maps will also lead to dligth discrepancies in display. if you were to overlay your GPS data on a properly projected image using a GIS package - chances are there will be no dispute. In fact I have done it before and there is no issue...hold on and I will show you

[straatvark]

theoretically you could get an approximation of altitude via topography + GPS position.

 

Do you have any idea how much space you would need on the garmin to store all that topo info?

 

And then to top it off, its not even really very accurate, so your elevation will be way off at end of the ride.

 

Just reset your barometer once a week and it should solve most of the issues

This statement reads better. (The height of trig beacons are not just published for the benefit of trail runners.)

[Stretch]

Slight accuracy improvement outside of google maps

 

strava

 

GPX file exported from strava and displayed in GIS

[Long Wheel Base]

Slight accuracy improvement outside of google maps

 

strava

 

GPX file exported from strava and displayed in GIS

lol on the GIS display it looks like you swerved for that car quite well hey Stretch

[Stretch]

lol on the GIS display it looks like you swerved for that car quite well hey Stretch

 

you laugh...that particular ride...a women did try and go through a red light at that exact same spot..i had to do some fancy footwork

[Long Wheel Base]

you laugh...that particular ride...a women did try and go through a red light at that exact same spot..i had to do some fancy footwork

Glad you still here to share the story!!

[Slowbee]

Glad you still here to share the GIS FILE!!

 

fixed

[Slowbee]

you must also bear in mind that the projection issues between geographic coordinates from the GPS and the google projection (which is a custom projection based upon lambert confromal conic) used in google maps will also lead to dligth discrepancies in display. if you were to overlay your GPS data on a properly projected image using a GIS package - chances are there will be no dispute. In fact I have done it before and there is no issue...hold on and I will show you

 

so back to the qstn. why is the garmin gps not so accurate on the height issue? The 705 has a firmware update, and the sportracks plugin has height correction module - but while the distances are reasonably consistent, the height not so much. Every now and then I seem to be underground

[Bobbo_SA]

Not sure if it has been mentioned in detail, but changing the frequency / sample rate of the logging will definitely assist with a smoother curve and more accurate data, but GPS is only accurate horizontally (depending on the number of satellites its using for the positioning) to within a few meters, in the vertical plane the accuracy is anything from 10 to 20m, thus going up and down steep hills you will notice a substantial difference compared to a system that is measuring wheel rotations / distance.

 

The newer devices that use barometric sensors are more accurate for vertical distance, assuming there is not a substantial change in the weather during the ride (riding into a storm etc) which is unlikely, and also that the unit calibrated the sensor correctly when it started up.

 

Barometric sensors can also vary in accuracy but a typical Bosch BMP180 / 085 is accurate to +-1m depending on sample rates, settings etc.

 

Another factor that will impact the accuracy is how the site uses the barometric and GPS data to determine the profile / distance traveled, there are a number of algorithms that they could be using.

[Slowbee]

Not sure if it has been mentioned in detail, but changing the frequency / sample rate of the logging will definitely assist with a smoother curve and more accurate data, but GPS is only accurate horizontally (depending on the number of satellites its using for the positioning) to within a few meters, in the vertical plane the accuracy is anything from 10 to 20m, thus going up and down steep hills you will notice a substantial difference compared to a system that is measuring wheel rotations / distance.

 

The newer devices that use barometric sensors are more accurate for vertical distance, assuming there is not a substantial change in the weather during the ride (riding into a storm etc) which is unlikely, and also that the unit calibrated the sensor correctly when it started up.

 

Barometric sensors can also vary in accuracy but a typical Bosch BMP180 / 085 is accurate to +-1m depending on sample rates, settings etc.

 

Another factor that will impact the accuracy is how the site uses the barometric and GPS data to determine the profile / distance traveled, there are a number of algorithms that they could be using.

so translation to plane eengliisshh, its ok, if the map shows you are underground, unless of course you ate some ground buying a plot, cause then technically you were underground,