Re: [gentoo-user] "Headless question": Harvesting the results...software needed.

Matti Nykyri <Matti.Nykyri@×××.fi> [14-10-01 00:26]:
> On Tue, Sep 30, 2014 at 08:12:38PM +0200, meino.cramer@×××.de wrote:
> > Matti Nykyri <matti.nykyri@×××.fi> [14-09-30 19:44]:
> > > > On Sep 30, 2014, at 17:12, Alec Ten Harmsel <alec@××××××××××××××.com> wrote:
> > >
> > > >
> > > >
> > > >> On 09/30/2014 10:05 AM, meino.cramer@×××.de wrote:
> > > >> Suppose the GPS would already be attached
> > > >> to the board and works...
> > > >>
> > > >> Is there any free available software and data for
> > > >> strict offline useage (which does NOT calls
> > > >> to home), which is able to map GPS data to a street/land
> > > >> map?
> > > >> I need both: The maps themselves and the logic to read
> > > >> GPS coordinates and map movements and ways to those maps.
> > > >>
> > > >> Is something like that available for free or should
> > > >> I directly ask the NSA/CIA/FBI/...?
> > > >>
> > > >> Thank you very much in advance for any help!
> > > >> Best regards,
> > > >> mcc
> > > > The only project I know of that has openly available map data is
> > > > OpenStreetMap (openstreetmap.org). I know they have an API, and they
> > > > probably (not sure) have maps available for download.
> > > >
> > > > afaik the only way to combine various map data out of the box is to use
> > > > a GIS package like QGIS. You can write software to do this using the
> > > > proj4 library for an embedded box, not sure if anything for your
> > > > specific use case already exists and is open source.
> > > >
> > > > Alec
> > >
> > > Sorry iphone send mail even if you don't wanna :/
> > >
> > > What you are considering doing is quite a challenge. What kind of coordinates does your gps module give you? The gps system works with cartesian x y z coordinates. Then these are usually displayed to the user in WGS-84. This is a quite hard mathematical problem (differential elliptical problem). Usually is done by your gps receiver and is approximated. GIS libraries have these functions built inside. Distances are easier and faster to calculate in cartesian coordinates. You need to calculate distance because coordinates from gps will never coincide with any address.
> > >
> > > Open street maps provides a very good start, but addresses have great differences in different countries. For example google misses addresses quite much depending on where you are searching. Getting the address right requires good locality from the program. Addresses and roads are vector maps. The fastest way to get address is to have the vector map of the world and then calculate distance to the closest address. The database will be huge :)
> > >
> > > Maps are usually raster pictures which have some projection. When you display them you can use 3d or 2d visual. In 3d (like google earth) you draw a sphere (or oblate spheroid) and draw textures on top of is to the right coordinates. In 3d everything needs to be converted to cartesian coordinates. Or in 2d you decide a projection and then convert the projection of your maps to this projection. After that it is just easy drawing. GIS libraries contain all the needed tools for these operations. There are a few of them with open source license.
> > >
> > > I have been doing some work with opengl 3d drawing maps. Good luck your project is quite big but it is sure very much fun :)
> > >
> > > --
> > > -Matti
> > >
> > >
> > >
> >
> > YEAH! Matti is back! I saw your previous mail and thought: Oh
> > boy...Clint Eastwood is very talkative compared to /him/. ;;;)))
>
> Trashed the phone... and now back to the good old fashion terminal
> connection.
>
> > I am not /that/ serious this evening...sorry...
> > With all the help from this forum this evening I got by far more
> > working results as I have thought...
> >
> > But back to your mail:
> > The GPS module I plan to use is this one (by Adafruit, Lady Ada):
> > https://learn.adafruit.com/adafruit-ultimate-gps/overview
> > From there (see link list on the left) you can also download
> > the manuals (pdf).
>
> Nice... MicroTek chipset. Quite easy to use.
>
> > I will not use this thing as a driving assistant or "navi" (is this
> > common speaking outside germany also...or is it one of those pseudo
> > english german words like "handy" for "cell phone"...dont laugh! This
> > time /I am/ serious! :) )
> >
> > Its more like a GPS data logger. I plan to copy the gathered data on
> > my PC later and I will try to "draw" them onto a map.
> > May be the results proof later, that I am able to walk through walls
> > and hovering over the face of the waters...;)
>
> Ok. This is easy... You just need some maps... openstreetmaps are good
> for that. From the MT3339 you get NMEA messages and WGS-84 coordinates.
> I would suggest displaying your results in 2D. For germany Lambert
> conformal conic projection is good choice. In this projection all angles
> are true and sreight lines are great circle routes. Just convert the
> maps to this projection and convert your coordinates to Lambert false
> easting and false northing and you will have cartesian coordinates that
> are easy to draw. Even excel is able to draw this in real time :) I don't
> see where you need the address resolution.
>
> > May be the UV-mappinga abillity of this 3D renderig program will help -- I am
> > using it for other purposes since 2006.
> > www.blender.org
>
> From what I know about blender isn't it just 3d rendering program. Not
> a GIS application. It doesn't know anythin about coordinates...
>
> > Will see how far it will go. First step in progress will be acchived,
> > when I can read any data from the GPS module and they are not that
> > changing if I dont move and they will change when I move. The module
> > is ordered and will arrive -- I hope -- next week.
>
> Nice.
>
> --
> -Matti
>

Hi Matti,

thanks for your explanation. If I start struggling...you will receive
email (ok?) !

Blender:
The UV-Mapping of blender maps 2D-Images to whatever shaped things in 
3D quite good...it is used for texturing.
Additionally Blender has a python API, so missing things can added.

Just a shot in the dark...

Best regards,
mcc