Lecture 9: Network analysis and Geocoding analysis

Question 1

Network data model

Answer 1

A data model created from another data model.
Consists of connected set of linear features formed from vector line
TOPOLOGY is an essential property

Question 2

Network

Answer 2

A set of edges connected to form join and loops

ALSO CALLED graph (undirected, directed, planar, non-planar)

Question 3

Edges

Answer 3

Also called links, chains, connections, relations

Question 4

Nodes

Answer 4

Also called points, junctions

Question 5

What is the geometry in network data model?

Answer 5

Nodes, arcs, stops, centre, turn

Question 6

What are nodes?

Answer 6

Interscection and interchanges

Question 7

What are stops?

Answer 7

Transferring of resources

Question 8

what are centres?

Answer 8

Discrete locations of resource supply

Question 9

what are turns?

Answer 9

Transition points

Question 10

What attributes are represented in the network data model?

Answer 10

Distance, attractiveness, impedance, supply, demand

Question 11

What is network analysis?

Answer 11

What is the shortest path
Description: Finding the minimum distance or cost path between an origin node and a destination node
Application: emergency planning

Question 12

What is the travelling salesman problem?

Answer 12

Description: With a number of location to visit, what is the least cost round trip starting at the one point

Question 13

What is geocoding analysis?

Answer 13

Geocoding is the process of assigning a point location within a coordinate system

Question 14

What are the 2 types of geocoding?

Answer 14

Direct and continuous: Uses the lat/long or projection coordinates (most accurate)
Indirect and discrete: Uses street address, CT, zip codes, accuracy depending on geocoding system

Question 15

What are some properties that is necessary to have in a street network file?

Answer 15

• Have to have the data available
• the data has to be up to date
• accurate attributes (such as street name, house address)

Question 16

What are the errors associated with geocoding?

Answer 16

• Interpolation of address (slight error when you take a point and place it on the street)
• Incorrect addresses
• human error

Question 17

What are some data errors and how can we solve them

Answer 17

1. Feature errors (Solution: editor toolbar and topology toolbar)
2. Attribute erros (Solution: Edit attribute table)
3. Projection and datum errors (Solution: Arc toolbox and re-project the data)