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<div class="moz-cite-prefix">The best results to prevent shortcuts
is a GPS system that will sample a coordinate when your direction
threshold crosses a customizable number of degrees. I've had
plenty of succes using about 23 to 26 degrees. This is not how
most handhelds work it seems. I think most of them work with
timers and some sort of algorithm to prevent spidering ( I go
deeper on this subject in this thread :
<a class="moz-txt-link-freetext" href="http://gis.stackexchange.com/questions/35215/detecting-lack-of-movement-on-gps-device">http://gis.stackexchange.com/questions/35215/detecting-lack-of-movement-on-gps-device</a>
)<br>
<br>
I'm using GPS tracers made by KCS (
<a class="moz-txt-link-freetext" href="http://trace.me/index.asp?page=hardware">http://trace.me/index.asp?page=hardware</a> ) , they wil send the data
over GPRS to a backend from where you can extract this data to any
format available.<br>
<br>
The results I have with these devices are pretty good. For
example: the cloverleaf in Mechelen (
<a class="moz-txt-link-freetext" href="http://www.openstreetmap.org/way/11186733#map=17/51.05095/4.50413">http://www.openstreetmap.org/way/11186733#map=17/51.05095/4.50413</a>
)<br>
was sampled with 3 units in 1 car, and a Garmin Etrex as control.<br>
<br>
I didn't manually / visually correct for mistakes, there where no
sat sources since this was new and google was like 2 years behind
bing (who was a year behind).<br>
<br>
But the point of all this is: if you want to avoid the cornering
artifacts: look for a way to sample using heading (degrees)
changes. Other sensors inputs can be : acceleration, distance.
Anything that is not timer based in fact. Timer based samples
pretty much suck. A combination of all should be perfect, as long
as timers are only taken while the asset is driving.<br>
<br>
Handhelds compensate (or try to) for this but at the cost of
accuracy of the result set. Sometimes by taking hundreds of
samples in a few seconds, of which plenty will be kind of 'cached'
and probably a few that timeout (in a 2 second timout a car does
make a significant distance ). The the postfilters try to sort
those out. It all depends very much on the implementation
quality of the handhelds. My 13 year old garmin etrex still
performs quite well given the age.<br>
<br>
Hope this helps,<br>
<br>
Glenn<br>
<br>
<br>
On 08-03-14 10:35, Marc Gemis wrote:<br>
</div>
<blockquote
cite="mid:CAJKJX-RC7=34uRQA-Tgd81GSUp9=hoZZJrxhAuePPrm7vevZwA@mail.gmail.com"
type="cite">
<div dir="ltr">The best I get with my Garmin Dakota 10 is 3-4m,
but in narrow streets or forests it might be worse. Another
setting on a Dakota is the number of tracking points. When you
don't record enough points you will notice that the track shows
shortcuts on corners.
<div>
<br>
</div>
<div>can't help with the osmtracker questions. Another place to
post questions is <a moz-do-not-send="true"
href="http://help.openstreetmap.org">http://help.openstreetmap.org</a>
, or <a moz-do-not-send="true"
href="http://forum.openstreetmap.org">http://forum.openstreetmap.org</a>
, just in case the Belgian community cannot help you with this
one.</div>
<div><br>
</div>
<div>regards</div>
<div><br>
</div>
<div>m<br>
<div><br>
</div>
</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Sat, Mar 8, 2014 at 9:30 AM, <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:ussapa@gmail.com" target="_blank">ussapa@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">I'm still
testing a few things, a.o. osmtracker. first headache was
the gps innacuracy. I am using a Samsung S2, and yesterday
osmtracker gave me a 40-50m accuracy, my first tracks looked
like my 3 years old drawing lines. Funny thing is that both
google maps and osmand could show my location with much more
precision !?<br>
searching for some web solutions, funny enough, unchecking
the 'use sensor aiding' helped a lot. I'm getting 5-20m now.
Is that the best I should expect or am I missing some
additional tweaking?<br>
<br>
As it seems, osmtracker is a standard in the field, I was
wondering if there is a custom belgian xml file available
for the buttons presets ?<br>
<br>
Thanks<br>
<br>
Nyamuk<br>
<br>
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</blockquote>
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<pre class="moz-signature" cols="72">--
"Everything is going to be 200 OK."</pre>
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