SphericalHTM: Spherical.Htm.Trixel Class Reference

Static Public Member Functions

static Int64 CartesianToHid20 (Cartesian v)

Convert a normalized Cartesian to a level 20 HtmID. if the paramater is a Cartesian.Nan, then 0, an invalid HtmID is returned (there are no integer NaNs).

static Int64 CartesianToHid (double x, double y, double z, int depth)

Convert a Cartesian coordinate to a HID.

static String XyzToHidName (double x, double y, double z, int depth)

Find the string representation of the HtmID to a given level of a unit vector.

static String ToString (Int64 hid)

Convert a HtmID to its textual representation.

static bool IsAncestor (Int64 grandpa, Int64 hid)

Decide whether or not a node in the tree of a given HtmID is an ancestor of another node.

static bool NameToTriangle (char[] name, out Cartesian c0, out Cartesian c1, out Cartesian c2)

Convert the location given by (x, y, z) to the symbolic text name of the HID WARNING: x, y, z are assumed to be normalized, so this function doesn't waste time normalizing.

Convert the named trixel to a triangle described by three vertices. The vertices are given by three arrays of three doubles. The coordinates of the triangles are given in the order (x, y, z) and so that the location is on the surface of a unit sphere.

static void ToTriangle (Int64 hid, out Cartesian a, out Cartesian b, out Cartesian c)

static bool IsValid (Int64 hid)

Decide if the given 64-bit integer is a valid HtmID.

static int ToName (char[] name, long hid)

Convert a 64-bit HID to a text desciption of the trixel.

static Int64 NameToHid (string sname)

Convert the trixel from text to 64 bit HID.

static Int64 Truncate (Int64 htmid, int level)

Truncate the HID to fewer bits The HID of a trixel implicitly contains the level of the trixel. When you need a lower level trixel that contains the trixel of the given HID, this function gives it to you. If the level of the given htmid is less than or equal to the desired level, then there is no change.

static Int64Pair Extend (Int64 htmid, int level)

Extend given HID to a desired level. The opposite of truncate. However, because there are many descendents, the result is a range of consecutive HIDs. The low and hi values are returned in the out variables.

static int LevelOfHid (Int64 htmid)

Returns the level number of an HID

Parameters:

htmid

The HID

Returns:: The level number or -1

Public Attributes

const int TrixelNameLength = 32

Maximum number of characters in text descriptions Whenever character arrays are used to keep the text description of a trixel, they must be exactly eMaxNameSize characters long.

Static Public Attributes

static readonly double Epsilon2 = 2.0e-8

This tolerance is used for comparing angles.

static readonly double Epsilon = 1.0e-14

This tolerance is used for comparing fractional roots.

static readonly double DblTolerance = 2.0 * Spherical.Constant.DoublePrecision

Twice the double precision tolerance.

Detailed Description

operations needed to convert between location and HtmID several representations of a HtmID, and locations expressed in Cartesian, J2000 (ra/dec) geographic lat/lon space. Since functions in the Spherical assembly convert to and from J2000 or geographic coordinates, only XYZ is handled by this class

Member Function Documentation

static Int64 Spherical.Htm.Trixel.CartesianToHid20 ( Cartesian v ) [static]

Convert a normalized Cartesian to a level 20 HtmID. if the paramater is a Cartesian.Nan, then 0, an invalid HtmID is returned (there are no integer NaNs).

Parameters:

Returns:: 64 bit HtmID

static Int64 Spherical.Htm.Trixel.CartesianToHid	(	double	x,
		double	y,
		double	z,
		int	depth
	)			`[static]`

Convert a Cartesian coordinate to a HID.

Given a Cartesian coordinate and a level number, it returns the 64 bit HID. WARNING! x, y, z are assumed to be normalized, so this function doesn't waste time normalzing.

Parameters:

	x	X coordinate of location
	y	Y coordinate of location
	z	Z coordinate of location
	depth	The level of the HID

Returns:: 64-bit HID

static String Spherical.Htm.Trixel.XyzToHidName	(	double	x,
		double	y,
		double	z,
		int	depth
	)			`[static]`

Find the string representation of the HtmID to a given level of a unit vector.

The vector must be normalized.

Parameters:

	x	double
	y	double
	z	double
	depth	int

Returns:: text representation of HtmID

static String Spherical.Htm.Trixel.ToString ( Int64 hid ) [static]

Convert a HtmID to its textual representation.

Parameters:

hid

64-bit HtmID

Returns:: The textual representation

static bool Spherical.Htm.Trixel.IsAncestor	(	Int64	grandpa,
		Int64	hid
	)			`[static]`

Decide whether or not a node in the tree of a given HtmID is an ancestor of another node.

Parameters:

	grandpa	64-bit HtmID, candidate for ancestry
	hid	64-bit HtmID who is the potential descendant

Returns:: true if grandpa is an ancestor of hid

static bool Spherical.Htm.Trixel.NameToTriangle	(	char[]	name,
		out Cartesian	c0,
		out Cartesian	c1,
		out Cartesian	c2
	)			`[static]`

Convert the location given by (x, y, z) to the symbolic text name of the HID WARNING: x, y, z are assumed to be normalized, so this function doesn't waste time normalizing.

Parameters:

	name	The text description of the trixel
	c0	The X coordinate
	c1	The Y coordinate
	c2	The Z coordinate

Returns:: true, if the conversion succeeded, false otherwise

static void Spherical.Htm.Trixel.ToTriangle	(	Int64	hid,
		out Cartesian	a,
		out Cartesian	b,
		out Cartesian	c
	)			`[static]`

Parameters:

	hid
	a
	b
	c

static bool Spherical.Htm.Trixel.IsValid ( Int64 hid ) [static]

Decide if the given 64-bit integer is a valid HtmID.

Parameters:

hid

64-bit input number

Returns:: true if given number is a valid HtmID, false otherwise

static int Spherical.Htm.Trixel.ToName	(	char[]	name,
		long	hid
	)			`[static]`

Convert a 64-bit HID to a text desciption of the trixel.

Parameters:

	name	An array of HtmTrixel.eMaxNameSize (a const in this class) character The array is null terminated.
	hid	The HID

Returns:: The size, or the length of the text

static Int64 Spherical.Htm.Trixel.NameToHid ( string sname ) [static]

Convert the trixel from text to 64 bit HID.

Parameters:

sname

The string with the text representation of the trixel.

Returns:: The 64 bit HID

static Int64 Spherical.Htm.Trixel.Truncate	(	Int64	htmid,
		int	level
	)			`[static]`

Parameters:

	htmid
	level

Returns:: HID of lower level trixel

static Int64Pair Spherical.Htm.Trixel.Extend	(	Int64	htmid,
		int	level
	)			`[static]`

Parameters:

	htmid	HID to extend
	level	New level to which to extend

Returns:: A pair of 64-bit HtmIDs

Member Data Documentation

readonly double Spherical.Htm.Trixel.Epsilon2 = 2.0e-8 [static]

This tolerance is used for comparing angles.

readonly double Spherical.Htm.Trixel.Epsilon = 1.0e-14 [static]

This tolerance is used for comparing fractional roots.

readonly double Spherical.Htm.Trixel.DblTolerance = 2.0 * Spherical.Constant.DoublePrecision [static]

Twice the double precision tolerance.

const int Spherical.Htm.Trixel.TrixelNameLength = 32

Maximum number of characters in text descriptions Whenever character arrays are used to keep the text description of a trixel, they must be exactly eMaxNameSize characters long.