garmin edge 705 questions plz

[alci4]

hi folks had the edge 705 for crimbo and love it but would like to pick the brains of the more knowledgable (than me) on the forum please

firstly doing my daily commute which on the edge normally comes in at just under ten miles but today i set the data recording settings to every second thinking that it would be more accurate but today my commute came in at 7.6 miles and i got no idea why as the map shows exactly the same route as every other day

secondly looking at my elevation graph setting off from home my elevation is 620ft but arriving home 7.5 (or 10) miles later my elevation at home was 517ft. graph jpeg below.

Am i missing somthing that will explain this or is my edge faulty

thanks for any help

 

[User269]

Take a look at the Garmin forum if nobody here knows the answer.

 

[fossyant]

There has been reports of glitches with 3.3 firmware although it's very dependant upon unit - no issues with mine.

Could be a glitch - see if it does this again over the next few days.

 

[zacklaws]

I don't really get the jist of your question, did you ride to work then later in the day ride home, or did you just go for a circular ride from your home and finish at your home, because your question seems to infer that you did both.

As for the altitude problem, it is quite common. What has happened is the barometric conditions have changed. Looking at a recorded weather chart of the Birmingham area today and the time of your ride, 0525, as indicated on your chart, in the space of about 15 mins later, the barometric pressure rose so that would give you a different starting altitude and finishing altitude to your home. Both my Edges 305 and 800 both record different altitudes if there is an alteration in barometric pressure. Its why aircraft have to reset there altimeters to always give the correct altitude, but unfortunatly we cannot do it with an Edge

 

[alci4]

hi it is a circular route but in three stages

i am a postman so i cycle to work about 5.30ish then out to my walk about 9.30ish then home again about 12ish

so i am commuting but it does end up being a big circular route from home to a to b to c

a = work
b = first delivery point on my walk
c = home again

thanks for the barometer info just couldnt work out if my altitude is 620ft at home at 05.30 how my house could drop just under 100 ft by midday lol

 

[Ticktockmy]

hi folks had the edge 705 for crimbo and love it but would like to pick the brains of the more knowledgable (than me) on the forum please

firstly doing my daily commute which on the edge normally comes in at just under ten miles but today i set the data recording settings to every second thinking that it would be more accurate but today my commute came in at 7.6 miles and i got no idea why as the map shows exactly the same route as every other day

secondly looking at my elevation graph setting off from home my elevation is 620ft but arriving home 7.5 (or 10) miles later my elevation at home was 517ft. graph jpeg below.

Am i missing somthing that will explain this or is my edge faulty

thanks for any help

May i ask, are up using OS references or Latitude and longitude, when you say you changed it to every second, is that seconds of time or seconds on Lat or long.
Have you got it set to WSG84 or some other data set? all these can change the accuracy

 

[alci4]

May i ask, are up using OS references or Latitude and longitude, when you say you changed it to every second, is that seconds of time or seconds on Lat or long.
Have you got it set to WSG84 or some other data set? all these can change the accuracy

O.M.G. now i'm lost lol

all i can tell you is that in the settings menu on the 705 in the data recording menu there is an option for recording data points which is every second or smart recording

all it says underneath is

"smart recording maximizes storage by recording data when it changes, for more detail every second can be used"

thats all i know sorry

 

[Jim_Noir]

Elevation I get this, it's to do with starting out from a waypoint with a known elevation IE one you have created. The other fix is to leave it outside turned on for 2 hours!

The distance, never had that on the Edge but get it all the time on my forerunner as it doesn't seem to pick GPS up to quick at start up.... I use sporttracks as that gives a better result from the data.

 

[zacklaws]

Elevation I get this, it's to do with starting out from a waypoint with a known elevation IE one you have created. The other fix is to leave it outside turned on for 2 hours!

As far as I know there is no fix, if the barometric pressure changes, then it cannot be recalibrated during the ride. The Edge will think your climbing if the pressure drops and decending if the pressure rises even though you may be on the flat. Also the elevation has nothing to do with the maps on the Edge either, its done by the barometric sensor

 

[Ticktockmy]

O.M.G. now i'm lost lol

all i can tell you is that in the settings menu on the 705 in the data recording menu there is an option for recording data points which is every second or smart recording

all it says underneath is

"smart recording maximizes storage by recording data when it changes, for more detail every second can be used"

thats all i know sorry

sorry, if I confused you, I would look at the handbook and set the unit back to default, find a measued distance, and cycle the route and see how it works out. If there are greater or less distance shown, again 10 meters is often the best you can be sure of, then you just use the hand book to rejust the distance settings. as to heights most hand held GPS do have trouble giving a true hieght measurement. for more than one reason

 

[Svendo]

As far as I know there is no fix, if the barometric pressure changes, then it cannot be recalibrated during the ride. The Edge will think your climbing if the pressure drops and decending if the pressure rises even though you may be on the flat. Also the elevation has nothing to do with the maps on the Edge either, its done by the barometric sensor

GPS provides 3D info, but the vertical is much less accurate than the horizontal. I don't think the edge is that good at balancing the two. I've had rides where the weather is dull and cloudy, often drizzly too, weather fronts passing overhead, and the altitude just hasn't worked at all. sometimes it gets going during the ride, other times it loses it at some point in the ride. I suppose the gps signal is weaker when overcast and due to rapid pressure fluctuations the altimeter is unreliable. Haven't had it happen recently though, which could be improvements in the algorithim with firmware updates, or I just don't go out inb the rain anymore!

 

[amaferanga]

1) Are you using a speed/cadence sensor and if so have you set the wheel size manually or is it calculating it automatically?

2) Are you waiting for your Edge to get a proper satellite lock before starting your ride?

 

[alci4]

1) Are you using a speed/cadence sensor and if so have you set the wheel size manually or is it calculating it automatically?

2) Are you waiting for your Edge to get a proper satellite lock before starting your ride?

1) yes m8 i am and it calculated it automatically

2) yes it only takes seconds for it to lock on and go to the info screens

 

[pshore]

firstly doing my daily commute which on the edge normally comes in at just under ten miles but today i set the data recording settings to every second thinking that it would be more accurate but today my commute came in at 7.6 miles and i got no idea why as the map shows exactly the same route as every other day

thanks for any help

I don't know the exact specs of the 705 but it is possible that by setting the recording to every second it records too many points for the available memory. If it reaches a limit, it will start to trim some points from your track log and so instead of a more accurate route round corners, it will start to straighten out. The 25% difference you said is probably too much for this to be a plausible explanation.

If 10 miles is correct, then 7 miles must be lost or no satellite reception as others have said above.

I think the only way you can get to the bottom of this is to get the track log (gpx file) off the unit and put it into some software such as bikeroutetoaster or routeconverter. Then you can see exactly where your track starts, ends and the exact points between.