[Freegis-list] Free GIS for realtime data and 3D visualization?

[Brent Wood]

--- Peter Fischer <peter_7003 at yahoo.com> wrote:

> Hi Brent,
>  
>  thank you very much for your answer, it was very helpful. One question:
>  the NVIZ component, could I use that isolated from the rest of GRASS GIS,
> i.e.
>  without all the other components to keep my system small and fast?


I wouldn't think so, but you might check the GRASS list for advice. NVIZ was
originally a separate packages, AFAIK, but whether it is still available that
way I don't know.

I believe it is likely that the GRASS data management tools etc will still be
useful.


>  Yet another question: Do you know whether there is a fast, thin client for
>  accessing Web Map Services (WMS) which does caching when getting raster
>  data (so that e.g. when I shift the current field of view, the client not
>  always has to reload new data from the server)? Whether 3D or only 2D plays 
>  no role, optional 3D would be nice, however.

I know OpenLayers does this (via tiles & using transparent images for each
layer), I'm not sure about other WMS/mapserver toolkits like Ka-Map!, MapLab,
FIST, etc.


>  And one last question: When I get realtime data from a server, e.g. GPS data
>  of
>  some object, is it possible to overlay that data over a map with a WMS
>  without storing the data in a database (which, I think would slow down the
>  realtime process because of the hard disk access)? Speed is an issue in my
>  scenario.

Yes. UMN mapserver scripts can do this pretty easily (I haven't done so, but
know others that have). Just choose your language :-)

I'd guess other WMS server packages have similar functionality. 

Of course, unless the users screen is automatically updating, it won't pick up
these changes anyway. Such updates will tend to make your maps somewhat behind
"real time", probably barely "near real time", but I don't see any way around
this when the general internet, with its latencies, etc, is used.

>  You would greatly help me since I am a newbie in this area, so be thanked in
>  advance for any help.

I ain't no expert, Just dabbled in 3D visualisation of midwater fishing data &
echo sounder data, so I picked up just enough to do what I needed :-)


Cheers,

  Brent Wood