Week1: 2A - Spatial Data Models: Object/Field/Vec/Raster

Question 1

Object-based model vs Field-based model

Answer 1

OBM: Individual objects are represented explicitly using their geometric counterpart
FBM: Spatial objects embedded in space
- described in terms of cells they intersect

Question 2

Vector-based vs Raster-based representations

Answer 2

VB: primitive spatial data objects are points, lines and polygons located through cartesian coordinates
RB: polygonal cells of equal size
Each cell has 2 associated values:
1) a positional value (identity)
2) attribute values of the underlying area it represents

Question 3

Spatial data models/formats

Answer 3

1) Vector

2) Raster

Question 4

Spatial data in vector format

Answer 4

Sets of spatial entities (points, lines, regions) & spatial relations (Topological, metric, direction) e.g. geographic maps, DTMs

Question 5

Spatial data in raster format

Answer 5

Sets of pixels e.g. satellite images, aerial photos, scanned maps