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Y3 T2 Geography 322 > Module 8 > Flashcards

Flashcards in Module 8 Deck (15)
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1
Q

Network

A

▪ a network is a system of interconnected lines (edges) and intersections (junctions)
that represent possible routes from one location to another

2
Q

Geocoding

A

▪ central to the use and analysis of networks is the need for places/features/points of interest to be accurately
positioned along the network, as well as a mechanism to
find each location – known as geocoding

▪ every entity of interest has a location and geocoding
translates that location (eg, latitude/longitude) into a
more conventional location system (street address)

3
Q

MAF/TIGER files

A
▪ the US Bureau of the Census produces the
most widely used geocoded geodatabases,
known as MAF/TIGER files
▪ these attribute fields allow input
addresses to be found (matched) in the
reference database
▪ in Canada, high quality geocoded data
must be purchased (Canada Post is a crown
corporation)
4
Q

Unmatched records in Geocoding

A
▪ unmatched (or tied) records can be handled either by relaxing the tolerances on
the automated process, or by manually assigning an address to each unmatched
record
▪ the ‘interactive rematch’
option in ArcGIS allows you
to view each unmatched
address and compare it to
likely matches
▪ this process is often
iterative and takes time, but
the goal should be to
reduce your unmatched
addresses to 0
5
Q

Undirected Network Analysis has steps(4)

A

1.Collect Source-Network Information
-Photogrammetric/LIDARgrammetric
Digitization

2.Build Topologically Correct Network
Dataset Elements
-edges (derived from lines-direction,1way or 2way), junctions (derived from intersections-4way stop, yeild) and turns(left, right, U)

  1. Specify Network Analysis
    - identify optimum route
    - find closest facility
    - identify service area
    - identify optimum delivery route
    - location-allocation modeling
  2. Solve the Network Analysis Problem and
    - Present Results
    - cartographic display
    - route instructions (turn-by-turn)
6
Q

▪ in shortest path analysis, you can
choose between straight-line or trueshape
distance

A
▪ straight-line distance – as the crow files
– is easily computed and doesn’t
necessarily need a topologically
correct network
▪ true-shape distance follows the
network of paths, producing a more
realistic measure of distance
7
Q

location-allocation modeling

A

: finding the best locations for one or more new
facilities that will service a given set of points and then assigning those points to
the facilities, taking into account factors such as the number of facilities
available, their cost, and the maximum impedance from a facility to a point

8
Q

Location-Allocation types:6

A
  1. Target Market Share
    - if money is available, helps facilities understand where they could grow in future
  2. Maximize Market Share
    - competing facilities will benefit from closer proximity
  3. Minimize Impedence
    - reduce travel time
  4. Maximize Attendence
    - how easy is it to travel to your location
  5. Minimize Facilities
    - same as maximize coverage but based on a restricted number of facilities
  6. Maximize Capacitated Coverage
    - capture people where demand exceeds supply
  7. Maximize Coverage
    - increase the ammount of people within the coverage area
9
Q

Directed Network Analysis has steps(

A
  1. Collect Source-Network Information
    - GPS
    - Photogrammetric/LIDARgrammetric
    - Digitization
2.Build Topologically Correct Network
Dataset Elements
edges (derived from lines)
junctions (source and intersections)
point and area ancillary features
-all causing impedence
  1. Specify Network Analysis
    - identify optimum route
    - find closest facility
    - identify service area
    - identify optimum delivery route
    - location-allocation modeling
  2. Solve the Network Analysis Problem and
    - Present Results
    - cartographic display
    - route instructions (turn-by-turn)
10
Q

Directed vs. Undirected

A

▪ directed networks differ from undirected networks in

that travel is allowed in only one direction

11
Q

Define Source Junctions and Sink Points

A

Directed Networks

▪ source junctions provide the material to the
network and pushes the material away from
itself (eg, the main sewer in your home)
▪ the sink point is the location where the material
or commodity is used, collected, or actually
leaves the network (eg, the sewage treatment
plant in the city)

12
Q

T OR F

Only Undirected Networks have impedence

A

F bpoth do

13
Q

Topology transforms the lines of the source network into …3

A

edges, junctions, and turns

14
Q

Network cost=

A

impedence

15
Q

barriers

A

.barriers are placeable objects in the network analysis and can be used to deny passage along an edge or through a junction