[Qgis-developer] Is QGIS supports dynamic display?

[Tendfly Niu]

Hi Zoltan,	Thanks a lot for your reply!	The version i'm using is QGIS 2.4.0. I want to develop a desktop application using QGIS API, by C++ as i said. It is not GPS, but the way it is displayed like GPS-dynamic displaying by the changing data. So i built QGIS using source code according to INSTALL. At the time of Cmake, I unchecked the Python related plugins(such as WITH_BINDINGS,WITH_STAGED_PLUGINS), hope this does not affact the function you mentioned.	Do you know which function or class is the one i'm looking for? I developed a simple demo that has these features: add layer, zoom in/out, pan. When i added a vector layer(.shp), i zoom in or zoom out, the refresh is not smooth or continuous. Are there any places i did not do right? Looking forward to your reply.
RegardsBob
Date: Mon, 11 Aug 2014 08:15:07 +0200
From: zoltans at geograph.co.za
To: qgis-developer at lists.osgeo.org
Subject: Re: [Qgis-developer] Is QGIS supports dynamic display?


  
    
  
  
    On 2014/08/11 04:11, 腾飞 牛 wrote:

    
    
      
      
        Dear all,
         I'm
          a new developer of QGIS using C++. I am doing a project which
          needs dynamically displaying maps/layers(just like GPS,layers
          automatically refreshing with the changing of object's
          position).I kown ARCGIS has the technique called dynamic
          diasplay(or something like that),which supports the capacity
          to do such things. Is QGIS has this ability? Any advices would
          be appreciated!
        

        
        Regards
        Bob
      
      

    
    

    Hi Bob,

    QGIS can definitely do this already.

    I used this feature in November last year - but make sure you use
    the latest versions of QGIS of all the plugins for field editing
    because at that stage some of the (digitising, I think) plugins
    caused serious loops when refreshing the screen or adding a feature,
    so not great if you are dynamically panning.

    

    I used a Garmin 60CSX, but any gps that can output an NMEA stream
    should work.

    You also need the free versions of Franson GPSGate from
    http://gpsgate.com/

    

    On a practical note, I found dynamic panning not very useful for my
    purpose. When we drove passed a POI, we couldn't easily pause the
    panning in order to drop a points and add the attributes needed. We
    found the dynamic tracking (digitising) of the incoming GPS track
    very useful, and we manually panned the display as needed, whilst in
    motion.

    

    HTH,

    Zoltan

    

    

    -- 

===========================================
Zoltan Szecsei PrGISc [PGP0031]
Geograph (Pty) Ltd.
GIS and Photogrammetric Services

P.O. Box 7, Muizenberg 7950, South Africa.

Mobile: +27-83-6004028
Fax:    +27-86-6115323     www.geograph.co.za
===========================================
  


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