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

[meino.cramer@gmx.de]

Matti Nykyri <matti.nykyri@iki.fi> [14-10-01 13:16]:
> > On Oct 1, 2014, at 5:54, meino.cramer@gmx.de wrote:
> > 
> > Matti Nykyri <Matti.Nykyri@iki.fi> [14-10-01 00:26]:
> >>> On Tue, Sep 30, 2014 at 08:12:38PM +0200, meino.cramer@gmx.de
> >>> wrote: Matti Nykyri <matti.nykyri@iki.fi> [14-09-30 19:44]:
> >>>>>> On Sep 30, 2014, at 17:12, Alec Ten Harmsel
> >>>>>> <alec@alectenharmsel.com> wrote:
> >>>>> 
> >>>>> 
> >>>>> 
> >>>>>> On 09/30/2014 10:05 AM, meino.cramer@gmx.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.
> 
> Of course you can do that, but it's gazillion times harder to do
> than 2d. If you want to have a good 3d visual (like google earth)
> you need to calculate your oblate spheroid on the fly and i don't
> think blender will be able to do that.
> 
> With basic UV-mapping you will have uneven distribution with poles
> compared to equator. The best solution is to use icosahedron (like a
> normal football with alternating hexagons and pentagons). Also with
> that you will automatically end up with triangles which are better
> for your GPU. Also the size of the triangles are even throughout the
> object. No tessellation is required. 
> 
> You will never need to draw more than one half of this spheroid
> because the other side is hidden an equal to the visual side. If you
> really wan't conserve memory of you GPU you can just have 1/8 of the
> vertices of the spheroid. The remaining 3/8 vertices can be created
> on the fly by a rotation matrix.
> 
> Even better choice is to have a fixed amount of vertices and draw
> only the needed parts of the sphere on the fly. You also need to
> calculate the coordinates for your texture.
> 
> To have see the goodies of 3d map view you probably want to have
> tilt with your visual. Otherwise there is not much difference with
> 2d view. The WGS-84 defines just the spheroid which does not
> describe earth accurately. Because earth's densities are not equal
> the height of mean sea level is not equal above the WGS-84 ellipse.
> To calculate that you need EGM (earth gravitational model). The
> result is called geoid. EGM96 is now mostly used but newer more
> accurate EGM2008 is also available. In maps and all other
> applications heights are always reported as above mean sea level.
> 
> To calculate coordinates, lets say N52 E16, you take the WGS-84
> ellipse that goes through the poles and is 16 deg east of 0 ellipse.
> Now the N52 is at the ellipse in the point where a normal to ellipse
> form 52deg angle with equator plane. To calculate where this point
> is at mean sea level or at arbitrary altitude you need to follow the
> vector of gravity. Vector of gravity does not have the same
> direction as the normal to the ellipse, but it is close. The gravity
> vector is twisted by the gravitational differences of earth (EGM)
> and the rotation of earth. These will give accurate result but in
> most applications it is not needed. A GIS library can do these
> calculations. Inverse of this is much much harder to do accurately
> (but every gps receiver needs to calculate it and usually use
> approximating algorithms).
> 
> So if you want to draw a map of lets say Aachen you it is not
> efficient to have vertices of the entire earth in GPU's memory. It
> is much better to have lets say 10000 points in Aachen and draw the
> texture on top of them an calculate the coordinates on the fly. If
> you are drawing areas bigger than Europe then you have more
> advantages with 3d view.
> 
> > Just a shot in the dark...
> 
> It would be nice to hear how well blender is able to do this :)
> 
> -- -Matti

Hi Matti,

I have the first result of trying to do as described: With my DSL
connection it is impossible to download the OSM data for offline
browsing. Reason: The duration for the download (~40GB) exceeds 24
hours. After 24 h my DSL line is forced to disconnect by the provider 
and the download fails.
Grrmmmpppfff...
Reminds me of times when modems were hi-tec...

I found another program called "viking" (sci-geosciences/viking),
which claims to be able to download all needed data/maps/etc... and
store them for later usage on harddisk. This is not exactky "offline"
but ... kind of "second hand offline" ;)

The idea to use blender was born in the moment when it seems
that I have to do all the mapping myself...no longer needed as
it seems.

Furthermore I installed sci-geosciences/gpsd and found this 
page: http://the8thlayerof.net/category/beaglebone-black/
which described how to connect the beaglebone black, the gps module I
ordered and gpsd.

Still waiting for the parcel to arrive...

Best regards,
mcc