Particle/null to anim texture map and particle/null position

[Nick3d]

Hi all,

I'm using the compound "Texture map as goal" in order to place my particles on a texture map
As it is works great and I have nice results, but what I would like to do is something like this:

Considering that I have an image completely black with one big red dot, once I start the animation the particles jumps to the red dot
What I would like to do is to keep all the particles at the center of the red dot by doing something like this

Fire a ray/vector to nord, east, south and west for each particle, in order to get the distance from the particle position to each "border", so I can set an average of nord+south/2, in order to keep it in the center, same thing for east and west

The same thing could be applied to a null instead of a particle, since it will follow the same principle of looking for the red dot and be in its center
And the same thing could be done if I "spawn" the particle by filtering the particle amount by a texture map

Any suggestions on how to setup a 4 rays/vectors?

Cheers

[Bullit]

The dot is a circle? so the center is the unique point at same distance of the border.

[Nick3d]

The dot is a circle? so the center is the unique point at same distance of the border.

Yes, it is a circle, but due to camera movement from the footage is not always a perfect shape, since it can look a bit squashed, thats why I need to calculate the center based on the distance on 4 different directions