Visualization Concepts

Preface

File Naming Conventions ix

1 Introduction

1.1 Why visualization? 1-2

1.2 Visualization techniques 1-4

1.2 Slicing air flow data 1-4

Figure A-1 Extruding loan data by geographical region 1-4

Figure A-2 Texture mapping 1-5

Figure A-3 Other techniques 1-6

Figure A-3 AVS/Express Examples library 1-6

1.3 From data to picture - how it works in AVS/Express 1-7

4. Reading data 1-7

4. Processing the data 1-7

4. Applying visualization technique(s) and viewing results 1-8

1.4 The next step - where to go from here 1-10

2 The Field:
The AVS/Express Data Model

2.1 The AVS/Express Field data structure 2-2

2.1 The importance of fields 2-2

2.2 Field basics 2-3

2.2 Field components 2-3

Grid and node data 2-3

Connectivity information 2-5

Figure B-5 Cell data 2-8

2.3 Meshes 2-10

2.3 Mesh types 2-10

Mesh types summary 2-10

Understanding Unstructured vs. Structured meshes 2-11

IMPORTANT: Mesh Type: uniform 2-12

Mesh type: rectilinear 2-13

Mesh type: structured 2-14

Unstructured mesh - cell sets required 2-14

Why mesh types matter 2-16

2.4 Mesh characteristics - ndim and nspace 2-18

Figure B-2 Examples 2-19

2.5 Support for Second Order Cells 2-21

Using 2nd order cells 2-22

2.6 Time Dependent (Multistep) Data 2-24

Note: Time-dependent data structure group objects 2-36

3
Example scenarios

3.1 Unstructured data 3-2

3.1 Point data 3-2

3.1 Multivariate data 3-4

3.1 Line data 3-5

3.1 A better way... 3-5

3.2 2D data 3-8

3.2 No coordinates 3-9

3.2 Multivariate 3-9

3.2 Common image file formats 3-10

3.3 3D data 3-11

Note: Uniform meshes 3-11

Note: Rectilinear meshes 3-13

Note: Unstructured meshes 3-14

Multi-variable 3-16

3.4 Managing your data 3-18

4 Importing Data

4.1 Why Import Data? 4-2

4.2 Mapping Data Into Fields 4-3

Field Mappers 4-3

Figure D-6 Table Mappers 4-9

4.3 Overview of Techniques for Importing Data 4-10

4.4 Using the AVS/Express Readers 4-11

Table D-1 netCDF reader and writer 4-11

4.5 Using Read_Column_File 4-12

Mapping the Data into a Field 4-12

Example 4-13

4.6 Data in AVS Field File Format (Read Field) 4-15

4.6 Reading in a Field File 4-16

4.6 Examples 4-16

4.7 Querying a Database 4-17

Figure D-1 Using the Table Mapper Modules 4-19

Figure D-2 Examples 4-21

4.8 Creating File Access Objects Using the Add File Import Module Tool 4-23

4.8 Using the Add File Import Module Tool 4-23

Example 4-24

4.9 Live Data Sources 4-27

Reading the Data In 4-27

4.10 Troubleshooting Tips 4-28

4.10 Verify Results One Step at a Time. 4-28

Note: Start with Simple Data 4-29

Note: Using the Correct Field Mapper 4-29

Note: For Problems with Reader Code, Divide and Conquer 4-29

5 Catalog of Visualization Techniques

5.1 The Data Visualization Libraries 5-2

5.1 Macros 5-2

5.1 DV prefix base modules 5-3

5.1 Mid-level and DV_Param macros 5-4

5.2 Overview of the Data Visualization Techniques 5-5

5.3 Visualization techniques 5-7

5.3 Exteriors and edges 5-7

5.3 edges 5-8

5.3 Contours, isolines, and isosurfaces 5-8

5.3 Slices and cross-sections 5-9

5.3 Colors, Lookup Tables (LUTs), and colormaps 5-10

5.3 Glyphs 5-11

5.3 Vector fields 5-12

5.3 City scapes, ribbon plots, and surface plots 5-12

5.3 Probes and interactions 5-14

5.4 Geometries 5-15

Example network 5-15

Figure E-1 Network Editor locations 5-17

Figure E-1 V locations 5-18

5.5 Data preprocessing 5-19

5.5 Combiners and extractors 5-19

5.5 Data filters 5-20

5.5 Interpolation 5-20

5.5 Cropping and cutting 5-21

5.5 Data sampling and regridding 5-22

5.5 Coordinate transformations 5-22

5.5 Conclusion 5-23

5.6 Image Processing 5-24

The Image Processing Libraries 5-25

Using the Image Processing objects 5-25

Note: Viewing images in a renderer 5-26

5.7 Adding your own image readers and writers 5-27

Implementing an image reader 5-27

Note: Implementing an image writer 5-30

Note: XIL on SUNOS5 5-32

5.8 Geographic Information System (GIS) Components 5-34

5.9 Accessing Data on the World Wide Web 5-36

Note: Virtual Reality Modeling Language (VRML) Output 5-37

6 Using the Animator and
Image Capture Modules

6.1 Keyframe Animation in AVS/Express 6-2

Understanding Keyframe Animation 6-2

6.2 Defining a Keyframe Animation 6-4

3. Instancing the animator Module 6-4

Figure F-1 Creating the Animation Keyframes 6-6

Figure F-2 Before adding keyframes 6-7

Note: Adding the first keyframe 6-8

Note: Adding additional keyframes 6-8

Modifying the Keyframes 6-9

6.3 Controlling what is Animated 6-11

The animate property 6-11

Rescanning the application for changes in the animatable parameters 6-12

Understanding the interpolation 6-12

6.4 Generating and Viewing the Animation 6-14

6.5 Capturing Viewer Images 6-16

Figure F-2 Using the Capture Controls 6-17

Figure F-3 Capturing images 6-18

Note: Controlling how the images are saved 6-19

Using the Playback Controls 6-19

Creating a Movie 6-20

7
Using the Data Viewers

7.1 Using the View Editor 7-2

Table G-1 Specifying the View Renderer, Size, and Color 7-3

Note: Specifying Display Output 7-8

Creating a New View 7-9

7.2 Using the Transform Editor 7-12

Specifying the Interactor Behavior 7-13

Setting a Transformation 7-16

7.3 Using the Light Editor 7-19

Note: Setting the General Light Attributes 7-19

Specifying Spot Light Attributes 7-24

Note: Manipulating Ambient Light 7-25

7.4 Using the View Object Editor 7-27

Note: Specifying an Object's General Attributes 7-28

Specifying Field Conversion Methods 7-30

Note: Set Image Data Conversions 7-33

Figure G-1 Setting Texture Conversions 7-36

Selecting Rendering Modes 7-37

Specifying View Object Properties 7-40

Specifying a Texture Mapping 7-50

7.5 Using the Camera Editor 7-53

Setting the Camera General Attributes 7-55

Setting the Camera Lens 7-57

Setting the Camera Tripod 7-61

Setting the Camera Clipping Planes 7-62

Setting the Camera Depth Cueing 7-63

7.6 Using The Datamap Editor 7-66

Understanding Datamaps 7-68

Specify a Data Range 7-69

Defining the Color Mapping 7-73

Note: Defining the Current Alpha Map 7-75

Figure G-5 Reading Datamap Files 7-76

7.7 Using the Graph Editor 7-79

Figure G-1 Setting the Graph Title 7-80

Setting the Graph Properties 7-82

Setting the Graph Style 7-85

Specifying Axes 7-86

Specifying Ticklines 7-88

Specifying the Appearance of the Legend 7-91

Specifying Contour Graph Characteristics 7-92

Specifying Colors In The Graph Editor 7-93