CS 770/870
Assignment 5. Flow visualization using a particle system

Purpose: Learn about flow visualization using particle traces. Learn about how to use trace color, width and transparency to enhance a representation.

Goals: Optimally show :the direction of flow, the strength of vector field, and as much detail as possible

The vector field is defined by the differential equationsprovided in the example code. You can change all the rest of the code, but do not alter the getVec function.

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

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

A data file is provided that contains a vector field from a NOAA fluid dynamics model of the Gulf of Mexico.


This is all about mapping velocity magnitude and direction to a variety of perceptual variables.

Your input variables are (dx,dy) = f(x,y) , where the function f defines of a vector field

Starting positions should be random

Display variables at your disposal are

Note: you can continuously seed the space or do it in one shot; e.g. with 5000 particles.

Particle traces should be drawn as quad strips.


Provide a written description of the way you have used visual variables to display the three required aspects of the data (approx 200-300 wds). Visual variables include such things as line width, contrast, background color, streak color, etc.

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 may also be mentioned.

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

Your best image (you can use <alt, PrintScreen>).

Due: November 25 by email (cware@ccom.unh.edu)