RE: [OpenMap Users] Speed Issues

From: Hudson Brian R Contr AFRL/IFSF <>
Date: Fri, 23 Jul 2004 13:22:28 -0000


You could change the VPFLayer so that it renders its list to a buffer
(BufferedImage) and then once complete, renders that image to the screen.

I work with some very large shape files, and I had to do a similar thing to
get chemical plumes animating without a serious loss in performance (due to
the rendering time required to redraw the thousands of points of the shape

You may want to take a look at the BufferedLayer, I believe you can add the
VPFLayer to this layer (it has its own MapBean) and it would handle the
buffering for you.

Hope this helps,

Brian Hudson

-----Original Message-----
From: [] On
Behalf Of Gatrell, Mark (UK)
Sent: Friday, July 23, 2004 4:38 AM
To: Openmap-Users (E-mail)
Subject: [OpenMap Users] Speed Issues

Hi all

        I am experiencing speed problems with my application...

        First the system:-
2.4Ghz P4
128MB GForce graphics card
80GB drive

        I have set a test OmPoly graphic rotating on the screen to simulate
a radar scan using a timer to update the position etc.

The sequence below is called on every timer expiry. I.E 10ms

This works fine until I turn on the VmapLevel1 data layer I.E railroads.When
the Vmap data layers are on, the sweeping of the graphic appears to jump a
few positions and then catches up with itself. I assume the rendering is

Has anyone any ideas as to why this is happening? and maybe what I can do to
improve this?

Any help is appreciated



  public void redrawTestIcon()

// Create the new OmPoly latlong positions

   anglePointA = azi - TestIconAngle/2; // gives points either side of the
heading to give a cone shape field of view
   anglePointB = azi + TestIconAngle/2;

    newLatLonPointsA = CalculateX_Y_UtmPoint(5000,anglePointA); // returns
an array of latlon points.
    newLatLonPointsB = CalculateX_Y_UtmPoint(5000,anglePointB);
        float[] llPoints = new float[8];
        float[] llPointsman = new float[8];
        llPoints[0] = vanLatPosition;
        llPoints[1] = vanLonPosition;
        llPoints[2] = newLatLonPointsA[0];
        llPoints[3] = newLatLonPointsA[1];
        llPoints[4] = newLatLonPointsB[0];
        llPoints[5] = newLatLonPointsB[1];
        llPoints[6] = vanLatPosition;
        llPoints[7] = vanLonPosition;

// Redraw the OmPoly






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Received on Fri Jul 23 2004 - 09:29:26 EDT

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