Class GraphDB

java.lang.Object

GraphDB

public class GraphDB
extends java.lang.Object

Graph for storing all of the intersection (vertex) and road (edge) information. Uses your GraphBuildingHandler to convert the XML files into a graph. Your code must include the vertices, adjacent, distance, closest, lat, and lon methods. You'll also need to include instance variables and methods for modifying the graph (e.g. addNode and addEdge).

Field Summary

Fields

Modifier and Type	Field	Description
private static double	K0	Scale factor at the natural origin, Berkeley.
private static int	R	Radius of the Earth in miles.
private static double	ROOT_LAT	Latitude centered on Berkeley.
private static double	ROOT_LON	Longitude centered on Berkeley.

Constructor Summary

Constructors

Constructor	Description
GraphDB(java.lang.String dbPath)	This constructor creates and starts an XML parser, cleans the nodes, and prepares the data structures for processing.

Method Summary

Modifier and Type	Method	Description
(package private) java.lang.Iterable<java.lang.Long>	adjacent(long v)	Returns an iterable over the IDs of all vertices adjacent to v.
(package private) double	bearing(long v, long w)	Returns the initial bearing between vertices v and w in degrees.
private void	clean()	Remove nodes with no connections from the graph.
private static java.lang.String	cleanString(java.lang.String s)	Helper to process strings into their "cleaned" form, ignoring punctuation and capitalization.
long	closest(double lon, double lat)	Returns the ID of the vertex closest to the given longitude and latitude.
double	distance(long v, long w)	Returns the great-circle distance between two vertices, v and w, in miles.
java.util.List<LocationParams>	getLocations(java.lang.String locationName)	Collect all locations that match a cleaned locationName, and return information about each node that matches.
java.util.List<java.lang.String>	getLocationsByPrefix(java.lang.String prefix)	In linear time, collect all the names of OSM locations that prefix-match the query string.
(package private) double	lat(long v)	Returns the latitude of vertex v.
(package private) double	lon(long v)	Returns the longitude of vertex v.
(package private) static double	projectToX(double lon, double lat)	Return the Euclidean x-value for some point, p, in Berkeley.
(package private) static double	projectToY(double lon, double lat)	Return the Euclidean y-value for some point, p, in Berkeley.
(package private) java.lang.Iterable<java.lang.Long>	vertices()	Returns an iterable of all vertex IDs in the graph.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

R

private static final int R

Radius of the Earth in miles.

See Also:

Constant Field Values

ROOT_LAT

private static final double ROOT_LAT

Latitude centered on Berkeley.

See Also:

Constant Field Values

ROOT_LON

private static final double ROOT_LON

Longitude centered on Berkeley.

See Also:

Constant Field Values

K0

private static final double K0

Scale factor at the natural origin, Berkeley. Prefer to use 1 instead of 0.9996 as in UTM.

See Also:

Constant Field Values

Constructor Detail

GraphDB

public GraphDB(java.lang.String dbPath)

This constructor creates and starts an XML parser, cleans the nodes, and prepares the data structures for processing. Modify this constructor to initialize your data structures.

Parameters:

dbPath - Path to the XML file to be parsed.

Method Detail

cleanString

private static java.lang.String cleanString(java.lang.String s)

Helper to process strings into their "cleaned" form, ignoring punctuation and capitalization.

Parameters:

s - Input string.

Returns:

Cleaned string.

clean

private void clean()

Remove nodes with no connections from the graph. While this does not guarantee that any two nodes in the remaining graph are connected, we can reasonably assume this since typically roads are connected.

lon

double lon(long v)

Returns the longitude of vertex v.

Parameters:

v - The ID of a vertex in the graph.

Returns:

The longitude of that vertex, or 0.0 if the vertex is not in the graph.

lat

double lat(long v)

Returns the latitude of vertex v.

Parameters:

v - The ID of a vertex in the graph.

Returns:

The latitude of that vertex, or 0.0 if the vertex is not in the graph.

vertices

java.lang.Iterable<java.lang.Long> vertices()

Returns an iterable of all vertex IDs in the graph.

Returns:

An iterable of all vertex IDs in the graph.

adjacent

java.lang.Iterable<java.lang.Long> adjacent(long v)

Returns an iterable over the IDs of all vertices adjacent to v.

Parameters:

v - The ID for any vertex in the graph.

Returns:

An iterable over the IDs of all vertices adjacent to v, or an empty iterable if the vertex is not in the graph.

distance

public double distance(long v,
                       long w)

Returns the great-circle distance between two vertices, v and w, in miles. Assumes the lon/lat methods are implemented properly.

Parameters:

v - The ID for the first vertex.

w - The ID for the second vertex.

Returns:

The great-circle distance between vertices and w.

closest

public long closest(double lon,
                    double lat)

Returns the ID of the vertex closest to the given longitude and latitude.

Parameters:

lon - The given longitude.

lat - The given latitude.

Returns:

The ID for the vertex closest to the lon and lat.

projectToX

static double projectToX(double lon,
                         double lat)

Return the Euclidean x-value for some point, p, in Berkeley. Found by computing the Transverse Mercator projection centered at Berkeley.

Parameters:

lon - The longitude for p.

lat - The latitude for p.

Returns:

The flattened, Euclidean x-value for p.

projectToY

static double projectToY(double lon,
                         double lat)

Return the Euclidean y-value for some point, p, in Berkeley. Found by computing the Transverse Mercator projection centered at Berkeley.

Parameters:

lon - The longitude for p.

lat - The latitude for p.

Returns:

The flattened, Euclidean y-value for p.

getLocationsByPrefix

public java.util.List<java.lang.String> getLocationsByPrefix(java.lang.String prefix)

In linear time, collect all the names of OSM locations that prefix-match the query string.

Parameters:

prefix - Prefix string to be searched for. Could be any case, with our without punctuation.

Returns:

A List of the full names of locations whose cleaned name matches the cleaned prefix.

getLocations

public java.util.List<LocationParams> getLocations(java.lang.String locationName)

Collect all locations that match a cleaned locationName, and return information about each node that matches.

Parameters:

locationName - A full name of a location searched for.

Returns:

A List of LocationParams whose cleaned name matches the cleaned locationName

bearing

double bearing(long v,
               long w)

Returns the initial bearing between vertices v and w in degrees. The initial bearing is the angle that, if followed in a straight line along a great-circle arc from the starting point, would take you to the end point. Assumes the lon/lat methods are implemented properly.

Parameters:

v - The ID for the first vertex.

w - The ID for the second vertex.

Returns:

The bearing between v and w in degrees.