A Visualization System for Tidal Basins

1
A Visualization System for Tidal Basins

• Kenrick Mock
• CS 470
• Proposal

2
System Overview

• Goal
• Develop a system to graphically visualize
  properties of tidal basins
• Client is Coastal Engineering
• Why
• Visualization will aid in the analysis of coastal
  erosion, effects of pollution, navigational
  access, and other aspects of waterways
• To visualize the system today, Coastal
  Engineering uses a manual process of loading data
  into Excel

3
Data Files

• Area of interest divided into 2D grid of cells.
  Five files containing source data.
• Depth
• Depth to basin floor, -99 to represent land
• Elevation
• Height of the water, indicates tide
• U velocity
• X velocity of water in a particular cell
• V velocity
• Y velocity of water in a particular cell
• Concentration
• Percentage of silt or other material in a
  particular cell

4
Data Source

• Physical Model
• Miniature version of the real thing
• Computer Model
• Fortran program
• Most data in this project generated from a
  computer model

5
Data File Format

• All files are in text
• Depth file example
• Mapping

-99.00 -99.00 3.96 3.96 -99.00 3.96 3.96
3.96 -99.00 3.96 3.96 -99.0



6
Time-Based Files

• Typically 2-5Mb in size
• Value of each cell specified for a time period

VERTICALLY AVERAGED BOD DAYS 2.0833334E-02
HOURS 0.5000000 -2.00 -2.00 1.00
1.00 -2.00 1.00 1.00 1.00 -2.00 1.00
1.00 -2.00 VERTICALLY AVERAGED BOD DAYS
4.1666668E-02 HOURS 1.000000 -2.00 -2.00
0.98 0.94 -2.00 0.98 0.95 0.93 -2.00
0.97 0.94 -2.00 VERTICALLY AVERAGED BOD DAYS
4.1666668E-02 HOURS 1.500000 -2.00 -2.00
0.94 0.92 -2.00 0.95 0.93 0.91 -2.00
0.94 0.87 -2.00
7
Visualization Using Excel

• Import data, assign colors based on values
• Slow!
• Especially slow for time-based data
• Solution Program to automatically visualize data

8
Specifications

• Dialog box to select data set
• Graphical display corresponding to the data in
  the tidal basin
• Play button to animate display for each time
  step
• A play button should be placed on the
  application that begins animating the graphical
  display for each time step.
• Concentration and Elevation should be displayed
  in different cell colors, with at least three
  levels of greyscale required and colors optional
• Display quantity E, essentially the inverse of
  concentration
• Velocity vector should be drawn in each cell
  specifying direction of velocity

9
Mock-up of Proposed Solution
Will use prototyping to incrementally refine the
system
10
System Specifications

• Windows 2000 or XP
• Visual Basic 6.0
• 256 Mb of memory, 450Mhz or higher
• 1024 by 768 pixel resolution

11
System Design

• For speed, load all data into memory
• Depth file 2D array
• Time-based files
• Dictionary of 2D arrays
• Simpler than a 3D array
• Dictionary is like a dynamic, content-based vector

12
Dictionary Data Structure
13
System Architecture
14
Addressing Flicker

• Screen update while cells are being re-drawn for
  the next time step can result in unpleasant
  flicker
• Use Double Buffering solution
• Draw new cell colors on the hidden screen
• Draw new vectors for velocities on the hidden
  screen
• Copy entire hidden screen to the visible screen

15
Planning
Estimated 156 hours total Requirements 15.6
hours Design 15.6 hours Implementation 43.7
hours Testing 49.9 hours Write-up 15.6
hours Presentation 15.6 hours
16
Schedule
17
Conclusion

• Goal is the delivery of a system to visualize
  tidal basins
• Many challenges
• Refining the design and specifications
• Lack of formal specifications is expected to lead
  to future specifications and requirements
• Prototyping methodology
• Proposed solution
• Utilize Visual Basics dictionary object, event
  processing, and easy UI design to construct a
  usable and powerful system