A4: Vector field representation (Due Oct 15)

Interactive Data Visualization Course

The purpose of this assignment is to learn something about the use particle systems + color and shape in representing a vector field.

Goals: Optimally show:

· Direction of flow

· Strength of vector field

· As much detail as possible

The vector field is defined by the following differential equations

The input is a position in the flow field. The output is the flow direction

void getVec(float X,float Y, float &dx, float &dy)

// this is the ODE that defines the flow

{

X *= 0.5;

Y = Y*0.9 – 0.05;

dx = 0.5 + sin(0.12*Y) ;

dy = 0.4* sin(0.4*X)+ 2.5*sin(0.1*X) +4.0*sin(0.06*X)*cos(Y*0.03) + 2.7*sin(0.015*X)*(1.0*0.5*cos(Y/50.0)) + 0.02*(Y-200);

}

visualize over the range

x from 0 .. 600 and

y from 0 .. 500 -- this should be your window size. (from glOrtho)

IDEAS

This is all about mappings

Your input variables are (dx,dy) = f(x,y) , that is, the specification of a vector field

Starting positions should be random

Display variables at your disposal are

1) The number of particles

2) The amount each particle moves on each iteration

3) The color of the particle (r,g,b) as a function of age

4) The size of the particle as a function of age

5) The background color

6) Placement of streamlines

Note: you can continuously seed the space or do it in one shot; e.g. with 1000 particles.

Deliverables:

Provide a written description of the way you have used the output variables to display the three required aspects of the data approx 300-400 wds. Comment on effects. E.g. how does gray scale change affect the presentation of direction in relation to the background value. Difficulties and possible solutions

Provide a code listing. Your code need not be sophisticated but it should be clear.

Your best image. Either that or single file source code to produce an image.

Do not get too involved. This should not be a major project.