[Freegis-list] GPS data processing

[Nils Faerber]

Am Mo, den 07.06.2004 schrieb Bernhard Reiter um 18:56:
> On Mon, Jun 07, 2004 at 03:17:22PM +0200, Nils Faerber wrote:
> > Am Mo, den 07.06.2004 schrieb Ayse Sayan um 15:10:
> > > I have a Trimble Lassen GPSreceiver. I want to make data processing
> > > from the raw data that I get from my receiver. I am a starter., So
> > > does anybody have an idea how I can start?
> Try to get an application that can get the date into your GNU/Linux system.
> A search revealed that the GPSreceiver speacks an NMEA protocol.
> www.freegis.org has five matches to that term:
> http://freegis.org/search.en.html?search=NMEA
> Many other probably also speak NMEA.

Not only probably - it is uncommon for most GPS receivers not to speak
at least some sort of NMEA, gpsbabel might also be of help for the ones
that don't.

> > I am sorry but I can not.
> > But this question seems to become a FAQ here and I am pretty sure that
> > there are some experts here on the list that could give some hints.
> Haven't had that impression lately.
> At least not when looking at the questions.
> It seems that there are several different questions.

Hmm... at least I recognised at least three questions that were centered
around the idea of postprocessing GPS data - for which reason ever.

> > So why not start a small "Dummy's Guide To GPS GIS Processing"?
> Because most people are not Dummies and I do not want to treat them 
> as being one. ;)

Argl... noone wanted to call them such.
But it is a common word nowadays to call the "getting started for
newbies" guides "dummie's guides". It was just meant as a humorous
expression and I really hope that I was not misunderstood.

> > I would be willing to contribute as far as I can!
> First processing steps for receiving GPS data is:
>  	a) Get the raw data somehow.
> 	b) (optional) correct it when using other references
> 	c) Convert it into the right format.
> 		If you have time information, you can create polygons (tracks)
> 		Otherwise you have points.

Concerning the polygons I searched for some solution to create those
from GPS data.
In most cases you will have GPS tracks that could be converted to
polygons - at least in theory. The trick is the "how-to" which I have
not yet found.
Interestingly for example GRASS has a digitizer option for some misc
graphics tablets but AFAIK no GPS data import. And I was also not able
to find any tool to convert GPS track data of any form into something
that some package like GRASS would be able to postprocess.

> Now you have a regular GIS layer and processing this further
> would be a GIS course subject.
> 
> There is a FreeGIS Tutorial section about using two GPS applications.
> It is in German:
> 	http://www.freegis.org/freegis_tutorial/online/node132.html

OK, I'll have a look at that!

> Note that gpsdrive and KFlog are interesting application for GPS data. :)

Sure.
But none of them allows to work with the collected data...

> 	Bernhard
CU
  nils faerber

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