squidpony.squidgrid.mapping

Class ProjectionTools

java.lang.Object

squidpony.squidgrid.mapping.ProjectionTools

public class ProjectionTools
extends java.lang.Object

Added to SquidLib by Tommy Ettinger on 7/4/2018, using MIT-licensed work by Justin Kunimune from his Map-Projections repo.

Constructor Summary

Constructors

Constructor and Description
ProjectionTools()

Method Summary

Modifier and Type	Method and Description
static double	hyperellipse(double y, double kappa) Part of computing a hyperellipse; takes only a y parameter corresponding to the y on a map and a kappa parameter used by Tobler's hyperelliptical projection to determine shape.
static double	simpsonIntegrateHyperellipse(double a, double b, double h, double kappa) Performs a definite integral using Simpson's rule and a constant step size; hard-coded to integrate a hyperellipse function.
static double[]	simpsonODESolveHyperellipse(double T, double[] y, double h, double alpha, double kappa, double epsilon) Solves a simple ODE using Simpson's rule and a constant step size; hard-coded to solve a hyperelliptical map projection task.

Methods inherited from class java.lang.Object

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

Constructor Detail

ProjectionTools

public ProjectionTools()

Method Detail

simpsonIntegrateHyperellipse

public static double simpsonIntegrateHyperellipse(double a,
                                                  double b,
                                                  double h,
                                                  double kappa)

Performs a definite integral using Simpson's rule and a constant step size; hard-coded to integrate a hyperellipse function.

Parameters:

a - The start of the integration region

b - The end of the integration region (must be greater than a)

h - The step size (must be positive)

kappa - the kappa value of the hyperellipse

Returns:

some magic stuff needed for Tobler Hyperelliptical maps

simpsonODESolveHyperellipse

public static double[] simpsonODESolveHyperellipse(double T,
                                                   double[] y,
                                                   double h,
                                                   double alpha,
                                                   double kappa,
                                                   double epsilon)

Solves a simple ODE using Simpson's rule and a constant step size; hard-coded to solve a hyperelliptical map projection task.

Parameters:

T - The maximum time value at which to sample (must be positive)

y - the double array to fill with samples; must not be null and must have length 1 or greater

h - The internal step size (must be positive)

alpha - part of the hyperelliptical projection's parameters

kappa - part of the hyperelliptical projection's parameters

epsilon - calculated beforehand using simpsonIntegrateHyperellipse(double, double, double, double)

Returns:

y, after modifications

hyperellipse

public static double hyperellipse(double y,
                                  double kappa)

Part of computing a hyperellipse; takes only a y parameter corresponding to the y on a map and a kappa parameter used by Tobler's hyperelliptical projection to determine shape.

Parameters:

y - y on a map, usually -1.0 to 1.0

kappa - one of the Tobler parameters

Returns:

I'm guessing the actual y used after hyperelliptical distortion; not sure