1. Spatial Data Models

2. Spatial Data Models Three common spatial data models Vector Raster
Triangulated Irregular Network (TIN)

3. Vector Data Model Defines discrete objects
Ex: Fire hydrants, roads, ponds, cadastre
3 basic types of vector data
Point
Line
Polygon
Composed of coordinates and attributes

4. Point Uses a single coordinate pair to define location
Considered to have no dimension
(They may have actual real-world dimensions, but for the purposes of a GIS, no dimension is assumed)
Attribute information is attached to the point
Ex: Light poles, manhole covers, crime location

6. Line Use an ordered set of coordinates to define location
Each line (and curve) is made up of multiple line segments
Occasionally, curved lines are represented mathematically
Starting point of a line is a node.
Intermediate point of a line is a vertex.
Attributes may be attached to whole line, or node, or vertex
Ex: Road, pipeline, object outlines, powerline

8. Polygon Formed by a set of connected lines
Polygons must close. The start and end point must have the same coordinate, or the polygon must close to an adjacent feature
Polygons have an interior region
Attribute information is attached to the polygon
Ex: Lake, city, tree stand, political boundary