## Sunday, June 29, 2008

### How we may use Google Earth Plugin? :-)

Some time ago Google introduces Google Earth Plugin.

Playing with this plug-in I tried to use GPS track from my visit in LA to create some kind virtual trip :-)

See in new window

Nice? :-) [you must remember that to see it you will need Google Earth Plugin and rather quick connection to the Internet]

Most important thing in this solution is using of GPS data not only to place us "in the World" but also to determine camera angle.
I decided to use vector created from current point and next point of GPS track [OK, truly it's not full GPS track but only some points], when I know this vector I may calculate camera angle.

`function fixAngle(angle,dx,dy) { if (dx==0) { if (dy>=0) angle = 90; else angle = 270; } else if ((dx>0) && (dy>=0)) { angle = angle; } else if ((dx>0) && (dy<0)) { angle = angle+=360; } else if ((dx<0)) { angle = angle + 180; } return angle%360;}[...] var dx = nx-x; var dy = ny-y; var angle = 0; if (dx!=0) { angle = Math.atan(dy/dx); } angle=angle/Math.PI*180; angle=fixAngle(angle,dx,dy);`Where `(nx,ny)` are coordinates of next point in track and `(x,y)` are coordinates of current point.

Btw. imagine, using this plug-in and some server we may build real-time and super realistic multiplayer flight simulator :-)

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