Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
9 Cards in this Set
- Front
- Back
|
Raster View of the World
|
Displays, locates, and stores graphical data by using a matrix or grid of cells. Unique reference coordinate represents each pixel either at corner or centroid. Each cell has discrete attribute data assigned to it
|
|
|
Resolution
|
Dependent on pixel or grid size
Must find balance between greater resolution vs. memory and processing constraints |
|
|
Components
|
Grids IDed by row and column
Area of celss defines resolution Grids labeled according to content |
|
|
Error - Relative vs. Absolute
|
Absolute: smaller pixels reduce absolute error, Worst Case: 49.9%
Relative: 25% error normally distributed |
|
|
Raster Advantages
|
Simple data structure
Overlay operations trivial High variability efficiently represented Used by digital images |
|
|
Raster Disadvantages
|
Data structure less compact
Topological relationships more difficult Edge Error Potential for low resolution |
|
|
Run-Length Encoding
|
Compression algorithm which replaces sequences ("runs") of consecutive repeated characters with a single character and the length of the run
|
|
|
Quad-Trees
|
Approach to region representation based on successive subdivision of an image into quadrants
|
|
|
Rastorization
|
Conversion of vector to rastor (overlaying grid over map and coding pixels according to occurrence of phenomena)
|
