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How Are Shortest Paths Found?
receive a lower ranking or end up plotted elsewhere or otherwise not properly matched. With more complete information (such as “1600 Pennsylvania
Avenue NW, Washington, D.C. 20003”) the system should be better able to
identify a more accurate match.
Also, the geocoding system can only properly identify locations if the line
segments are in the reference database. If you’re searching for an address
established after the reference database network file was put together, the
system will not be able to properly match the address. If the point is plotted on the correct street but at an incorrect location on the street, it’s likely a
problem with address range data in the reference database and how it reflects
the real world (for instance, a house at #50 Smith Street is not necessarily
halfway down a street segment that begins with 2 and ends with 100). The
geocoding will usually be only as accurate as the base data it is being matched
to. If the reference database does not contain all line segments (for instance,
subdivisions, streets, or new freeway bypasses that haven’t been mapped and
added to the reference database), or if its attributes contain inaccurate address ranges or incorrect or missing attributes, the geocoding process will
likely be unable to accurately match the addresses or may plot them in the
wrong location.
New methods for geocoding addresses to get a more accurate match are
being developed. Rather than using a line segment and interpolating the address location, point databases are being created in which a point represents
the center of a parcel of land (for instance, a house or a commercial property).
When geocoding with this point data, address information can get matched
to the point representing the parcel, and the address location can be found for
the road immediately next to the parcel.
Once locations are geocoded, the system (or GIS) can begin to examine
the routes between locations to determine the shortest path from one location to another. With a vehicle navigation system, you enter the address of
the destination you want to travel to, and the system will match that address.
The device’s current position is determined using GPS and plotted on the
network map (and this will be the origin). With two points, the system will
then compute the shortest route between the origin and destination across
the network. The same holds true for an online system to find directions—it
has a matched origin and destination and will compute what it considers the
best route for you to follow between the two points. With so many different
ways to get from the origin to the destination, the system now needs a way to
determine the “shortest path” between these locations.
How Are Shortest Paths Found?
When you leave your home to go to work, you likely have several different
ways you can go. Some of them are very direct and some of them are very
roundabout, but you have plenty of options available. If you want to take the
“shortest” path from home to work, you’d likely focus on some of the more
How Are Shortest Paths Found?
receive a lower ranking or end up plotted elsewhere or otherwise not properly matched. With more complete information (such as “1600 Pennsylvania
Avenue NW, Washington, D.C. 20003”) the system should be better able to
identify a more accurate match.
Also, the geocoding system can only properly identify locations if the line
segments are in the reference database. If you’re searching for an address
established after the reference database network file was put together, the
system will not be able to properly match the address. If the point is plotted on the correct street but at an incorrect location on the street, it’s likely a
problem with address range data in the reference database and how it reflects
the real world (for instance, a house at #50 Smith Street is not necessarily
halfway down a street segment that begins with 2 and ends with 100). The
geocoding will usually be only as accurate as the base data it is being matched
to. If the reference database does not contain all line segments (for instance,
subdivisions, streets, or new freeway bypasses that haven’t been mapped and
added to the reference database), or if its attributes contain inaccurate address ranges or incorrect or missing attributes, the geocoding process will
likely be unable to accurately match the addresses or may plot them in the
wrong location.
New methods for geocoding addresses to get a more accurate match are
being developed. Rather than using a line segment and interpolating the address location, point databases are being created in which a point represents
the center of a parcel of land (for instance, a house or a commercial property).
When geocoding with this point data, address information can get matched
to the point representing the parcel, and the address location can be found for
the road immediately next to the parcel.
Once locations are geocoded, the system (or GIS) can begin to examine
the routes between locations to determine the shortest path from one location to another. With a vehicle navigation system, you enter the address of
the destination you want to travel to, and the system will match that address.
The device’s current position is determined using GPS and plotted on the
network map (and this will be the origin). With two points, the system will
then compute the shortest route between the origin and destination across
the network. The same holds true for an online system to find directions—it
has a matched origin and destination and will compute what it considers the
best route for you to follow between the two points. With so many different
ways to get from the origin to the destination, the system now needs a way to
determine the “shortest path” between these locations.
How Are Shortest Paths Found?
When you leave your home to go to work, you likely have several different
ways you can go. Some of them are very direct and some of them are very
roundabout, but you have plenty of options available. If you want to take the
“shortest” path from home to work, you’d likely focus on some of the more