GPS and N800; plotting where you have been?

[cLin]

Is there a way for me to basically leave my GPS receiver/N800 on and have it save my location every X minutes and either give me the file with the data or post it online somewhere? It'll be interesting to see my travel distance and activity after a while.

[ghoonk]

you're not checking on the wife and kids, are you?

just kidding ;)

[cLin]

Not that old yet :P

I just like to look at data. Plus, new toy, want to do useless things with it.

That is an interesting idea though...

[DJames1]

I haven't really checked this in Wayfinder or Maemo Mapper, but most GPS packages have a track-log function. Let's see... Maemo Mapper appears to be able to save tracks in GPX format. Then you can use this site to visualize in Google Earth: http://www.gpsvisualizer.com/map?form=googleearth

[fredoll]

yes MaemoMapper can do this for you !

[fpp]

There's also GPSTracer :
http://david.hautbois.free.fr/joomla/index.php?option=com_content&task=view&id=98&Itemid=61

[cLin]

Thanks guys! Another GPS related question: I have the Holux M1000 and since my SD card hasn't come in yet I just fiddle with the GPS location option in the control panel. When I was on the street, it says my altitude is 30~ M. Is this altitude suppose to be above sea level altitude or altitude from the road below me?

[tso]

wild guess, sea level...

[DJames1]

Altitude is a more complex question than it seems. Your GPS measures position relative to satellite orbits. It doesn't know the altitude of the local terrain below you since it doesn't have a detailed world DEM (digital elevation model). Even "mean sea level" (often used as a reference on local maps) isn't a world constant since it varies between oceans. Instead GPS receivers have a rough model of the shape of the earth which they use as their reference "datum" (see http://en.wikipedia.org/wiki/Datum).

Different GPS receivers report the altitude in different ways, so they don't always agree with each other. Also nav software may correct the altitude reported by the GPS receiver to a different reference. You have to check the documentation for your particular GPS receiver and nav software to be sure.

[sgosnell]

Short, non-technical answer - mean sea level. That's not entirely true, and the actual answer is far longer and more technical than you probably care to read, but that's close enough. It's certainly not above the road below, because the GPS knows nothing at all about roads, mountains, or anything else on the earth. Mapping software might, but the GPS doesn't. It just knows the distance to the satellites it's tracking, nothing else.

Maemo Mapper will plot your location, show it on the maps you download, and transfer the tracks to a file if you want. The file can be imported by a number of apps for further massaging.

[TA-t3]

The globe isn't a perfect sphere, and an accurate model of the globe isn't really feasible in a small consumer-grade GPS. So even when the GPS can calculate accurate altitude (which in general they can't do as accurate as location) it'll still be incorrect. However, the error is in the same range depending on where you live, so it's possible to add a look-up table with correction factors to GPS software (you could, for example, add such a function to MM). Where I live the altitude error is around 38 meters, a few hundred km south of me I'm told it's 43 meters. And so on.

(Altitude in reference to "mean sea level" of course, as described by the earlier posters)