[OSM-newbies] Data layer doesn't look like track shape

[Andy Robinson (blackadder)]

Anne Wilson wrote:

>Sent: 23 April 2008 9:01 PM

>To: newbies at openstreetmap.org

>Subject: Re: [OSM-newbies] Data layer doesn't look like track shape

> 

>On Wednesday 23 April 2008 20:10:08 Thomas Wood wrote:

>> >  > Track log interval is set (from the main menu - press 'find' twice)

>by

>> >  > picking tracks, then set-up, then 'auto' & 'most often'.

>> >

>> >  I can't see that.  Set-up offers me time, display, units, interface

>and

>> >  system.  None of them refer to interval.

>> 

>> Its under Traces and then Setup (It is confusing, I also hadn't found

>> the option there until after owning the unit for a year!)

>> 

>By Traces, do you mean the screen that shows the shape?  The options there

>are

>orientation, autozoom, hide waypoints and show bearing line.

> 

>The good news, though, is that the manual definitely says 'Update Rate:

>1/second, continuous'.

> 

>> The USB stuff doesn't apply here, I think the confusion is that you're

>> using a serial to usb device? You should use whatever linux /dev/ that

>> is created when plugged in.

>> gpsbabel expects the unit to be in Garmin data transfer mode.

> 

>Which is where I started :-)  So, the trace produced by the gpsbabel

>command

>should download the whole log?

> 

 

Anne, just to be clear, according to the manual for your eTrex H
(http://www8.garmin.com/manuals/eTrexH_OwnersManual.pdf) on page 18 it
confirms that you can set the tracklog defaults. The spec for the unit also
confirms you can store 10,000 trackpoints. All good. The norm for a detailed
track as has been said before is to set the "Record Interval" to "Time" and
a 1 second interval. Make sure the "wrap log when full" is not ticked. This
means that when the log is full (after just under 3 hours of mapping) the
tracklog will turn off and you will no longer see your trace continuing on
the trace screen. Mostly we download the tracklog after each trip out
mapping and the clear the log back to zero before we go out mapping again.
This keeps the tracklogs clear as to what they cover and reduces unnecessary
duplication.

 

Others hold the view that you can use the devise over a longer period of
time by leaving the device tracklog settings at "auto". This means you can
get a much longer use from the unit before the log is full. The alternative
is to adjust to 2, 3 or 5 sec etc to ensure you the unit will be logging for
the duration you are out. I would recommend you only change back to "auto"
once you can see how the log is working and get the visual feedback in the
OSM editors.

 

Note though that converting a 1sec interval tracklog directly to an osm data
layer doesn't really work. Too many nodes and fluctuation. Yes you can
filter the track when its converted to GPX with gpsbabel but that's just an
extra task you shouldn't have to do unless you want to do it that way. Much
easier, especially for areas of the map that already have some data, to use
the tracklog (gpx trace) as a guide to the drawing of ways over the top of
it.

 

Hope this helps clarify a few things.

 

 

In case you need to compare, this gpsbabel command takes the tracklog (-t)
and the waypoints (-w) from the device (I too am using a serial to USB
converter but under windoze) 

 

-w -t -i garmin -f com3: -o gpx -F "path\filename.gpx"

 

Hope this helps narrow down any remaining questions.

 

Cheers

 

Andy

 

 

>Anne

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