Data Models Flashcards
1
Q
5 GIS functional elements
A
- data acquisition: gathering data
- preprocessing: manipulating data
- data-management: organizing data
- manipulation and analysis: info generation
- product generation: generate out for consumption
2
Q
Define abstraction
A
Ignoring elements that are not relevant to the main focus
3
Q
Space is occupied by
A
- a continuous field with no boundaries
- discrete objects with properties and mapping
4
Q
Continuous vs discrete data
A
Continuous: represented by raster
Discrete: represented by vector
5
Q
What is the smallest physical grouping of a map layer?
A
Map resolution
6
Q
Why is layered data useful?
A
- reduces complexity
- reduces data records
- can have many combinations
7
Q
Attributes of a vector point
A
ID, x and y coordiantes
8
Q
Attributes of a vector line
A
ID, length, x and y nodes and vertices
9
Q
Attributes of a vector polygon
A
ID, area, length, x and y nodes and vertices, left/right poly
10
Q
Explain raster cells
A
- homogenous units
- area = spatial reosultion
11
Q
Explain rater tessellation
A
- tiles with no overlaps and no gaps
Example: square grid, triangular grid, and hexagonal grid
