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

[Peter Fischer]

Thank you all for your answers, Brent, Markus, Daniel and Paul,


  It looks like GRASS GIS (because of its 3D capabilities) and/or UMN MapServer
are good choices for me. Some details (especially concerning WMS/WFS/WCS)
are still not that clear to me. At best the following could be realized by a GRASS
GIS configuration which conforms to a WMS/WFS/WCS architecture:


  Some questions do I have to your answers:


1. I thought the WMS server puts      together the data it gets from the WFS  
    (vector/feature data) and from the      WCS  (raster  data) into a single raster
    image?
2. Daniel, as far as I have      figured out, WFS basic is without write access, and 
    WFS-T (transactional)      is with write access. Do UMN MapServer or GRASS
    GIS (Markus) already      support this? It would be important to be able not only to
    change styles      (like with the SLDs) but to do annotations (I tried FIST on their
    site,      its nice, but annotations failed when I tried – the map wasn’t displayed
    any more) or even change the vector data already stored in the vector      layer   
    database (WFS for example).
3. With GRASS GIS, is it possible      that when the user interacts with one view (in 
    the tablet PC ), he also      manipulates (shift, zoom,  change  layer) the other view
    (in the table)? If      not yet, would GRASS GIS be customizable to do so?
4. Does GRASS GIS (even over a      WMS/WFS/WCS infrastructure) support POIs 
    so if the user clicks on a point      in a map I can reference to a database to 
    display information about the      object (POI) he clicked onto?
5. In the same constellation      (GRASS GIS with WMS/WFS/WCS), is display of
    realtime vector data coming in      from sensors like GPS signals overlayed over
    the map possible? –  The architecture would be an additional      data source (to   
    WFS and WCS) with the GPS signals and the WMS puts them together      to
    one raster image and sends them to the multiple  views? – By the way,       the   
    views are different, not identical.


    So it would be nice to realize such an architecture, if possible solely with
GRASS GIS or, if reasonable, together with UMN MapServer.


  I can not thank you often enough for your help so far, it would be awesome if you
could also answer the questions above. – Many thanks and till soon, I will let you
know my decision and experiences I will get with it.


  Best regards,


  Peter.


Daniel Calvelo <dca.gis at gmail.com> wrote: Hi Peter, in the following I assume you opt for OGC protocols.

On 3/13/07, Peter Fischer 
 wrote:
[...]
> Is it possible with WMS (maybe using Styled Layer Descriptors, SLD) to write
> back vector data into the layers stored on the server (WFS for vector data I
> guess)? Or is access read-only?

That is up to your client application. In the WMS protocol you ask for
a map (and specify its appearance with SLD) and get an image, so you
would have to code in javascript or some other client-side tool the
means to send back mouse/keyboard events according to position within
the image, and a server-side thingie to feed those to a database.

OGC defines WFS-T, the transactional web feature service, which aims
at webservice-based vector editing. For a nice demo and framework, see
the FIST site.

> Is it possible that the views interact with each other, e.g. on the tablet
> shifting the map displayed onto the table (in the other view) or switching
> to another map/layer?

That should be provided by your server, it seems quite feasible. You
will have to pool the server continiously for updates if you wish to
make them resemble real-time.

> Are there raster layers in WMS/WFS I can switch on and off?

Of course. Each layer is in fact a different WMS request.

> Can I define points of interest (POI) so if the user clicks on a point in a
> map I can reference to a database to display information about the object
> (POI) he clicked onto?

See the first point above. MapServer allows for this kind of x,y query natively.

> Can I control the contents of the view (shift, zoom etc.) from the outside
> e.g. by a script/program, or are there only the manipulators in the view's
> interface for zooming, shifting the map cutout displayed in the view (e.g.
> the GRASS viewer or others)?

Sorry, I don't quite get this one.

HTH, Daniel.

-- 
-- Daniel Calvelo Aros



 
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