Chapter 8
Describe how junctions and edges are used to represent real world networks.
*Junctions are LOCATIONS* 1. highway entrances/exits 2. freeway overpasses 3. underpasses 4. subway stops 5. rail terminals *Edges are LINES* 1. streets 2. highways 3. railroads 4. light-rail systems 5. subway lines 6. foot paths
Describe how the process of address matching or geocoding enables you to derive a spatial location (and hence a geocoded, x, y, location)
*Process of Address Matching*: 1. reference database in place 2. address parsing 3. address standardization 4. address matching (but only an approximation of where the point should be) *ONCE THE ADDRESS IS PLOTTED*: -some systems can compute the lat/longitude coordinates -geocoded points have spatial reference attached to them for further use as a geospatial dataset
develop a spatial analysis question and apply the spatial analysis tools of AGOL to this question
*Questions*: -how many objects of a particular type are within certain distance? -how do you choose the most suitable location on a set of criteria? *Analysis tools*: 1. buffer 2. dissolve 3. geoprocessing 4. spatial query 5. overlay 6. intersect 7. identity 8. symmetric difference 9. union (overlay) 10. map algebra
route-finding
*Things to Take into Consideration*: - minimize time spent driving - highway routes only - driving distance - no city streets - always keep to main roads
TIGER/Files
*def*: a file produced by the US Census Bureau that contains (among other items) the line segments that correspond with roads all over the US -*TIGER* = Topologically Integrated Geographic Encoding Referencing -delineate boundaries (block groups or congressional districts)
network
*def*: a series of junctions and edges connected together for modeling concepts such as streets
edges
*def*: a term used for the links in a network (lines or links)
junctions
*def*: a term used for the nodes (or places where edges come together) in a network (point locations or nodes)
transit cost
*def*: a value that represents how many units (of time or distance, for example) are used in moving along a network edge -actual distance in miles from one junction to another along the edge -or the equivalent time it takes to drive that particular segment
address parsing
*def*: breaking an address up to its component parts -1009 | 13th | St | Corvallis | OR | 97333
reference database
*def*: the base network data used as a source for geocoding -ex: a road network that addresses can be matched to
connectivity
*def*: the linkages between edges and junctions of a network
Define the spatial concept of *connectivity* while modeling a network
*def*: the linkages between edges and junctions of a network -*proper*: all junctions and edges should connect to one another, while things that should NOT connect, do NOT -example: even though in a 2D plane, a road and a railway intersect, your GPS system won't tell you to turn onto the railway when you're traveling!
geocoding
*def*: the process of using the text of an address to plot a point at that location on a map -another term: address mapping
1. TIGER files typically contain what?
1. Names of Streets 2. Zip code information for streets 3. Address ranges on streets!
7. In a GIS network, an "edge" represents:
A link in a network
What is integrated with a network data BASE to provide a vehicle navigation system?
NAVSTAR GPS!
4. The tool used for viewing imagery at a particular location on a road is:
Street View
10. The number of units to travel along a link of a network is:
Transit cost
2. In a GIS network, a "junction" represents:
an intersection on the network
5. Linear Interpolation is used in geocoding to:
find the exact point where an address is matched to
3. Setting up the components of an address in a regular format describes:
standardization
6. Destinations to visit on a network are referred to as:
stops
8. In order to match an address to a particular street, what fields are necessary to have in the reference database?
the city name and zip code of the street address
