How do you move a graphic smoothly on the map?

Question

I've got a car (graphic) that I get a new location every second.

Is there an easy way to move the car smoothly on the map? rather than having the car move in a jerky type motion?

thanks,

MarkBaird · Answer

I had another flash of inspiration for working out interim points!  It would be far easier if you did this:

- Take your old point and your new point and make them into a 2 point polyline

- Densify the line to the number of interim points you want.  See GeometryEngine.desify

- Crack open the geometry to extract the points which make up the densified polyline

- Move the graphic to each interim point for a very short period of time (you'll need to experiment with this)

The above method would work with any spatial reference.  Not such an exciting solution from a software engineering point of view, but much easier.

MarkBaird · Answer

If you want to update the location of a graphic you just need to apply a new geometry to it.  This sample shows the basics.

This sample shows how you can do this with a 3D symbol.

If however your jerky movements are due to your point moving a large distance then you'll need to write some interpolation code to achieve this.  You can work out interim points for a smooth motion by using Bresenham's line algorithm - Wikipedia which is pretty easy to implement if you are working in a projected coordinate system.  I'm sure there are other alternatives you could try.

Does that help?