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USING GIS FOR TRANSPORTATION ANALYSIS
Geocoding and Routing with an Addressed Road Network
What Is Geocoding?
Geocoding is the process of creating a geographic coordinate from an address. It is the digital equivalent of placing a push pin on a map.
This makes it possible to easily place a list of addresses on a map
How Does Geocoding Work?
The Way an address is geocoded is by comparing the number, street name and direction information of a location to an addressed roads network.
An addressed roads network consists of a GIS layer containing segments representing streets with their direction, and a database containing the street name, direction information, and a range of address numbers from one intersection to the next for each direction.
The exact location of an address in a given block is determined by a mathematical proportion. For example the fictitious address 266 4TH AVE E is placed on the north side of the road, at a point 2/3 along the length of 4th Avenue from it's intersection with Washington Street.
Uses In Transportation
There are many potential uses for GIS and geocoding in transportation planning and analysis.They can be divided into 4 broad categories: Location Analysis, Proximity Search, Routing, and Road/Traffic Analysis.
Location Analysis
involves studying patterns in the distribution of persons, objects or places. An example is an agency or business encouraging car pooling matching employees who live in the same neighborhood
Proximity Search
is finding the number of persons, objects or places which fall within a specified distance from any point. A useful example of this would be finding the number of current riders who are within easy walking distance of a proposed new bus stop.
Routing
is determining the path of a vehicle from one point to the other. The shortest distance and fastest travel time are two of the most commonly used criteria. In this example, the shortest distance route is shown between the location of a fire and the nearest fire station
Road/Traffic Analysis
involves mapping conditions of the street network itself. This example maps the traffic speed past sensors placed during rush hour along a major arterial road.
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