Package com.geodesk.core

Class Mercator

java.lang.Object
com.geodesk.core.Mercator
public class Mercator extends Object
Methods for working with Mercator-projected coordinates. GeoDesk uses a Pseudo-Mercator projection that projects coordinates onto a square Cartesian plane 2^32 units wide/tall (in essence, the value range fully uses a 32-bit signed int; a pair of coordinates fits into a 64-bit signed long). This projection is compatible with Web Mercator EPSG:3785, except that instead of meters at the Equator, it uses a made-up unit called "imp" ("integer, Mercator-projected"). See Coordinate System

  • Constructor Summary

    Constructors
    Constructor
    Description
    Mercator()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    area(Geometry geom)
    Calculates the area of the given geometry (in square meters).
    static double
    deltaFromMeters(double meters, double atY)
    Calculates the equivalent number of imps that are equal to the given distance in meters at a planar-projected latitude.
    static double
    distance(double x1, double y1, double x2, double y2)
    Calculates the Euclidean distance between two projected points.
    static double
    distance(Coordinate c1, Coordinate c2)
     
    static double
    distance(Geometry a, Geometry b)
     
    static Envelope
    envelope(double lon1, double lat1, double lon2, double lat2)
     
    static Envelope
    expandEnvelope(Envelope env, double meters)
     
    static double
    latFromY(double y)
    Converts a projected latitude to WGS84.
    static double
    lonFromX(double x)
    Converts a projected longitude to WGS84.
    static double
    metersAtY(int y)
     
    static void
    project(Geometry geom)
    Converts the WGS84 (longitude/latitude) coordinates of a Geometry into Mercator projection.
    static double
    scale(double y)
     
    static double
    xFromLon(double lon)
    Converts a longitude to imps.
    static int
    xFromLon100nd(int lon)
    Converts a longitude to imps.
    static double
    yFromLat(double lat)
    Converts a latitude to imps.
    static int
    yFromLat100nd(int lat)
    Converts a latitude to imps.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Mercator

      public Mercator()

  • Method Details

    • xFromLon

      public static double xFromLon(double lon)
      Converts a longitude to imps.
      Parameters:
      lon - longitude (in degrees)
      Returns:
      equivalent imps

    • xFromLon100nd

      public static int xFromLon100nd(int lon)
      Converts a longitude to imps.
      Parameters:
      lon - longitude (in 100-nanodegree increments)
      Returns:
      equivalent imps

    • yFromLat

      public static double yFromLat(double lat)
      Converts a latitude to imps.
      Parameters:
      lat - latitude (in degrees)
      Returns:
      equivalent imps

    • yFromLat100nd

      public static int yFromLat100nd(int lat)
      Converts a latitude to imps.
      Parameters:
      lat - latitude (in 100-nanodegree increments)
      Returns:
      equivalent imps

    • scale

      public static double scale(double y)

    • lonFromX

      public static double lonFromX(double x)
      Converts a projected longitude to WGS84.
      Parameters:
      x - projected latitude (in imps)
      Returns:
      equivalent WSG-84 longitude in degrees

    • latFromY

      public static double latFromY(double y)
      Converts a projected latitude to WGS84.
      Parameters:
      y - projected latitude (in imps)
      Returns:
      equivalent WSG-84 latitude in degrees

    • metersAtY

      public static double metersAtY(int y)

    • distance

      public static double distance(double x1, double y1, double x2, double y2)
      Calculates the Euclidean distance between two projected points. A simple method that is sufficiently accurate only for short distances.
      Parameters:
      x1 - (in imps)
      y1 - (in imps)
      x2 - (in imps)
      y2 - (in imps)
      Returns:
      distance in meters

    • distance

      public static double distance(Coordinate c1, Coordinate c2)

    • distance

      public static double distance(Geometry a, Geometry b)

    • deltaFromMeters

      public static double deltaFromMeters(double meters, double atY)
      Calculates the equivalent number of imps that are equal to the given distance in meters at a planar-projected latitude.
      Parameters:
      meters - distance in meters
      atY - the projected latitude (i.e. in imps, not degrees)
      Returns:
      the distance in imps

    • area

      public static double area(Geometry geom)
      Calculates the area of the given geometry (in square meters). A simple method that is sufficiently accurate only for small areas.
      Parameters:
      geom - the geometry
      Returns:
      area in square meters

    • expandEnvelope

      public static Envelope expandEnvelope(Envelope env, double meters)

    • envelope

      public static Envelope envelope(double lon1, double lat1, double lon2, double lat2)

    • project

      public static void project(Geometry geom)
      Converts the WGS84 (longitude/latitude) coordinates of a Geometry into Mercator projection. The Geometry is modified in-place.
      Parameters:
      geom - the `Geometry` whose coordinates to project