geod

package module
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 Go to latest Published: May 7, 2024 License: MIT Imports: 8 Imported by: 0

README

Pure Go geodesy calculations based on https://github.com/chrisveness/geodesy/ by Chris Veness.

Documentation

Index

Constants

View Source 
const (
	FormatDeg       = iota // degrees
	FormatDegMin           // degrees+minutes
	FormatDegMinSec        // degrees+minutes+seconds
)

FormatDeg, FormatDegMin and FormatDegMinSec are constants the control how FormatDMS should format the degree value.

View Source 
const MercatorMaxLat = Degrees(85.05112877980644)

Variables

This section is empty.

Functions

func Distance 

func Distance(start, end LatLon, model EarthModel, modelArgs ...interface{}) units.Distance

Distance returns the distance in `DistanceUnits` between points `start` and `end` using the given `model`.

Arguments:

start - starting point end - end point (destination) model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns the distance in `DistanceUnits` If the distance cannot be calculated an invalid is returned, which can be tested using `DistanceUnits.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) p2 := geod.NewLatLon(12.1, -23.2) dist := geod.MidPoint(p1, p2, geod.VincentyModel, WGS84) // WGS84 can be omitted, it's the default and only 

`Ellipsoid` currently defined

metres := dist.Metres()

func FormatDMS 

func FormatDMS(deg Degrees, format, dp int) string

FormatDMS converts decimal degrees to a string in deg/min/sec format Degree, prime, double-prime symbols are added, but sign is discarded, though no compass direction is added. Degrees are zero-padded to 3 digits; for degrees latitude, use slice [1:] to remove a leading zero.

Arguments:

`deg` - degrees to be formatted as specified. `format` - one of FormatDeg, FormatDegMin or FormatDegMinSec (degrees, degrees+minutes, degrees+minutes+seconds) `dp` - number of decimal places to use - use -1 for defaults: 4 for d, 2 for dm, 0 for dms.

func MultiPolygonToMercator added in v0.0.5 

func MultiPolygonToMercator(mp orb.MultiPolygon) orb.MultiPolygon

func SetEarthRadius 

func SetEarthRadius(r float64)

SetEarthRadius can be used to [globally] change the value of Earth's radius (in metres) used for spherical Earth calculations (includes rhumb). Default is 6371000m

Types

type Cartesian 

type Cartesian Vector3D

Cartesian represents ECEF (earth-centered earth-fixed) geocentric cartesian coordinates

func (Cartesian) LatLonEllipsoidal 

func (c Cartesian) LatLonEllipsoidal(ellipsoid Ellipsoid) LatLonEllipsoidal

LatLonEllipsoidal converts this (geocentric) cartesian (x/y/z) coordinate to a (geodetic) latitude/longitude point on specified ellipsoid. Uses Bowring’s (1985) formulation for μm precision in concise form; `The accuracy of geodetic latitude and height equations' B R Bowring, Survey Review vol 28, 218, Oct 1985.

Argument 

ellipsoid - the Ellipsoid to use for the conversion

Returns LatLonEllipsoidal - Latitude/longitude point defined by cartesian coordinates, on given ellipsoid.

Example c := geod.Cartesian{X: 4027893.924, Y: 307041.993, Z: 4919474.294} p := c.LatLon(geod.WGS84()) // 50.7978°N, 004.3592°E

type Degrees 

type Degrees float64

Degrees angle Defining it as a type makes it harder to mix Degrees and Radians in your code, you're welcome :)

func DegreesFromRadians 

func DegreesFromRadians(radians float64) Degrees

DegreesFromRadians takes an argument in radians and returns it in degrees

func FinalBearing 

func FinalBearing(start, end LatLon, model EarthModel, modelArgs ...interface{}) Degrees

FinalBearing returns the final bearing having travelled from `start` to `end` using the given `model`.

Arguments:

start - starting point end - end point (destination) model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns the final bearing in `Degrees` from North If the bearing cannot be calculated NaN value is returned, which can be tested using `Degrees.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) p2 := geod.NewLatLon(12.1, -23.2) bearing := geod.FinalBearing(p1, p2, geod.SphericalModel)

func InitialBearing 

func InitialBearing(start, end LatLon, model EarthModel, modelArgs ...interface{}) Degrees

InitialBearing returns the initial bearing going from `start` to `end` using the given `model`.

Arguments:

start - starting point end - end point (destination) model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns the initial bearing in `Degrees` from North If the bearing cannot be calculated NaN value is returned, which can be tested using `Degrees.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) p2 := geod.NewLatLon(12.1, -23.2) bearing := geod.InitialBearing(p1, p2, geod.SphericalModel)

func ParseDMS 

func ParseDMS(dms string) (Degrees, error)

ParseDMS parses a string representing Degrees-Minutes-Seconds into decimal degrees This is very flexible on formats, allowing signed decimal degrees, or deg-min-sec optionally suffixed by compass direction (NSEW); a variety of separators are accepted. Examples -3.62, '3 37 12W', '3°37′12″W'. Example: lat := geod.ParseDMS("51° 28′ 40.37″ N") lon := geod.ParseDMS("000° 00′ 05.29″ W") ll := geod.LatLng{Latitude: lat, Longitude: lng} <--- 51.4779°N, 000.0015°W

func Wrap90 

func Wrap90(degrees Degrees) Degrees

Wrap90 constrains `degrees` to range -90..+90 (e.g. for latitude); -91 --> -89, 91 --> 89.

func Wrap180 

func Wrap180(degrees Degrees) Degrees

Wrap180 constrains `degrees` to range -180..+180 (e.g. for longitude); -181 --> 179, 181 --> -179.

func Wrap360 

func Wrap360(degrees Degrees) Degrees

Wrap360 contrains `degrees` to range 0..360 (e.g. for bearings); -1 --> 359, 361 --> 1.

func (Degrees) Radians 

func (d Degrees) Radians() float64

Radians takes an argument in degrees and returns it in radians

func (Degrees) RoundTo 

func (d Degrees) RoundTo(n int) float64

RoundTo returns the degrees as a float rounded to `n` decimal points.

func (Degrees) Valid 

func (d Degrees) Valid() bool

Valid returns true if the angle is valid. Invalid angles are returned by functions when the result cannot be calculated.

type EarthModel added in v0.0.5 

type EarthModel func(LatLon, ...interface{}) Model

type Ellipsoid 

type Ellipsoid struct {
	// contains filtered or unexported fields
}

Ellipsoid parameters The only ellipsoid defined is WGS84, for use in utm/mgrs, vincenty, nvector.

func WGS84 

func WGS84() Ellipsoid

WGS84 is a standard ellipsoid used in cartography, geodesy, and satellite navigation including GPS

type LatLon 

type LatLon struct {
	Latitude  Degrees
	Longitude Degrees
}

LatLon represents a point on Earth defined by its Latitude and Longitude

func DestinationPoint 

func DestinationPoint(start LatLon, distance float64, bearing Degrees, model EarthModel,
	modelArgs ...interface{}) LatLon

DestinationPoint returns the destination point going from `start` having travelled `distance` on the given initial bearing, using the given `model`.

Arguments:

start - starting point distance - distance travelled, in metres -- Note: I might change this to DistanceUnits in the future (FIXME) bearing - initial bearing in `Degrees` from North model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns the final point (destination) If the point cannot be calculated an invalid point is returned, which can be tested using `LatLon.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) bearing := geod.Degrees(23.2) p2 := geod.Destination(p1, 100000.0, bearing, geod.RhumbModel) // 100kms from p1 heading 23.2 along a rhumb line

func IntermediatePoint 

func IntermediatePoint(start, end LatLon, fraction float64, model EarthModel,
	modelArgs ...interface{}) LatLon

IntermediatePoint returns the point at the given fraction between `start` and `end`.

Arguments:

start - starting point end - end point (destination) fraction - the fraction between the two points (0.0 = `start`, 1.0 = `end`) model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns the intermediate point at the given fraction. If the point cannot be calculated an invalid point is returned, which can be tested using `LatLon.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) p2 := geod.NewLatLon(12.1, -23.2) pInt := geod.IntermediatePoint(p1, p2, 0.24, geod.VincentyModel)

func IntermediatePoints 

func IntermediatePoints(start, end LatLon, fractions []float64, model EarthModel,
	modelArgs ...interface{}) []LatLon

IntermediatePoints returns a slice of points at the given fractions between `start` and `end`. This is far more efficient than multiple `IntermediatePoint` calls in a loop as some of the expensive calculations are reused and each franctional point is calculated in parallel.

Arguments:

start - starting point end - end point (destination) fractions - slice of fractions between the two points (0.0 = `start`, 1.0 = `end`) model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns slice of intermediate points at the given fractions. Points that cannot be calculated are returned as invalid points, can be tested using `LatLon.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) p2 := geod.NewLatLon(12.1, -23.2) pInt := geod.IntermediatePoint(p1, p2, 0.24, geod.VincentyModel)

func MidPoint 

func MidPoint(start, end LatLon, model EarthModel, modelArgs ...interface{}) LatLon

MidPoint returns the point halfway between `start` and `end` using the given `model`.

Arguments:

start - starting point end - end point (destination) model - a function that converts a `LatLon` to a structure appropriate for the `Model` to be used 

This is how you select the model you wish to use for the calculations. See the description of `Model`
for list of available functions.

modelArgs - additional arguments to pass to the `model` function, if needed, for example the `Ellipsoid` 

for ellipsoid models.

Returns the halfway point. If the point cannot be calculated an invalid point is returned, which can be tested using `LatLon.Valid()`

Example: p1 := geod.NewLatLon(10.1, -20.0) p2 := geod.NewLatLon(12.1, -23.2) mid := geod.MidPoint(p1, p2, geod.SphericalModel)

func NewLatLon 

func NewLatLon(latitude, longitude float64) LatLon

NewLatLon returns a `LatLon` structure with the given latitude and longitude

func ParseLatLon 

func ParseLatLon(args ...interface{}) (LatLon, error)

ParseLatLon parses a latitude/longitude point from a variety of formats.

Latitude & longitude (in degrees) can be supplied as two separate string parameters or as a single comma-separated lat/lon string

The latitude/longitude values may be signed decimal or deg-min-sec (hexagesimal) suffixed by compass direction (NSEW) a variety of separators are accepted. Examples: -3.62, '3 37 12W', '3°37′12″W'.

Thousands/decimal separators must be comma/dot

Arguments: lat|latlon - Latitude (in degrees), or comma-separated lat/lon [lon] - Longitude (in degrees).

Returns Latitude/longitude point on WGS84 (LatLon)

Example: p1 := ParseLatLon(51.47788, -0.00147) // numeric pair p2 := ParseLatLon("51.47788", "-0.00147") // string pair p3 := ParseLatLon("51°28′40″N, 000°00′05″W") // single dms string p4 := ParseLatLon("51°28′40″N", "000°00′05″W") // dms lat string, dms lon string

func (LatLon) Equals 

func (ll LatLon) Equals(other LatLon) bool

Equals returns true if `ll` and `other` have identical Latitude and Longitude values

func (LatLon) MercatorPoint added in v0.0.5 

func (ll LatLon) MercatorPoint() MercatorPoint

MercatorPoint converts the Latitude/Longitude pair to a X/Y coordinates using Mercator projection. The resulting coordinates will be in the [0..1] range, so for rendering images, multiply by the horizontal and vertical resolution. Latitudes over MercatorMaxLat are not supported.

func (LatLon) Valid 

func (ll LatLon) Valid() bool

Valid returns true if the coordinates are valid. Invalid coordinates are returned by functions when the result cannot be calculated.

type LatLonEllipsoidal 

type LatLonEllipsoidal struct {
	LatLon
	Height float64
	// contains filtered or unexported fields
}

LatLonEllipsoidal represents latitude/longitude points on an ellipsoidal model earth, with ellipsoid parameters and methods for converting points to/from cartesian (ECEF) coordinates.

This is the core struct, which will usually be used via LatLonEllipsoidalDatum or LatLonEllipsoidalReferenceFrame.

func NewLatLonEllipsodial 

func NewLatLonEllipsodial(latitude, longitude Degrees, height float64) LatLonEllipsoidal

NewLatLonEllipsodial creates a new LatLonEllipsoidal struct

func ParseLatLonEllipsoidal 

func ParseLatLonEllipsoidal(args ...interface{}) (LatLonEllipsoidal, error)

ParseLatLonEllipsoidal parses a latitude/longitude point from a variety of formats

Latitude & longitude (in degrees) can be supplied as two separate string parameters or as a single comma-separated lat/lon string

The latitude/longitude values may be signed decimal or deg-min-sec (hexagesimal) suffixed by compass direction (NSEW) a variety of separators are accepted. Examples: -3.62, '3 37 12W', '3°37′12″W'.

Thousands/decimal separators must be comma/dot

Arguments: lat|latlon - Latitude (in degrees), or comma-separated lat/lon [lon] - Longitude (in degrees). [height] - Height above ellipsoid in metres.

Returns Latitude/longitude point on WGS84 ellipsoidal model earth (LatLonEllipsoidal)

Example: p1 := ParseLatLon(51.47788, -0.00147) // numeric pair p2 := ParseLatLon("51.47788", "-0.00147") // string pair p3 := ParseLatLon("51°28′40″N, 000°00′05″W", 17) // dms string + height p4 := ParseLatLon("51°28′40″N", "000°00′05″W", 17) // dms lat, dms lon, height

func (LatLonEllipsoidal) Cartesian 

func (l LatLonEllipsoidal) Cartesian() Cartesian

Cartesian converts the point from (geodetic) latitude/longitude coordinates to (geocentric) cartesian (x/y/z) coordinates Returns the Cartesian point equivalent to lat/lon point, with x, y, z in metres from earth centre.

func (LatLonEllipsoidal) Equals 

func (l LatLonEllipsoidal) Equals(other LatLonEllipsoidal) bool

Equals checks if the `other` point is equal to this point

Example p1 := geod.LatLonEllipsoidal{52.205, 0.119, geod.WGS84()} p2 := geod.LatLonEllipsoidal{52.205, 0.119, geod.WGS84()} equal := p1.Equals(p2) // true

type LatLonEllipsoidalVincenty 

type LatLonEllipsoidalVincenty struct {
	// contains filtered or unexported fields
}

LatLonEllipsoidalVincenty represents a point used for calculations using a the Vincenty method, on an ellipsoidal Earth model.

func NewLatLonEllipsodialVincenty 

func NewLatLonEllipsodialVincenty(latitude, longitude float64, ellipsoid Ellipsoid) LatLonEllipsoidalVincenty

NewLatLonEllipsodialVincenty creates a new LatLonEllipsoidalVincenty struct

func (LatLonEllipsoidalVincenty) DestinationPoint 

func (llv LatLonEllipsoidalVincenty) DestinationPoint(distance float64, bearing Degrees) LatLon

DestinationPoint returns the destination point having travelled the given `distance` along a geodesic given by `initialBearing` from `llv`, using Vincenty direct solution

Arguments:

distance - Distance travelled along the geodesic in metres initialBearing - Initial bearing in degrees from North

Returns the destination point

Example p1 := geod.NewLatLonEllipsodialVincenty(-37.95103, 144.42487, geod.WGS84()) p2 := p1.DestinationPoint(54972.271, geod.Degrees(306.86816)) // 37.6528°S, 143.9265°E

func (LatLonEllipsoidalVincenty) DistanceTo 

func (llv LatLonEllipsoidalVincenty) DistanceTo(dest LatLon) units.Distance

DistanceTo returns the distance along the surface of the earth from `llv` to `dest` using Vincenty Inverse calculation

Argument:

dest - destination point

Returns the `Distance` between this point and destination point in DistanceUnits

Examples: p1 := geod.NewLatLonEllipsodialVincenty(52.205, 0.119, geod.WGS84()) p2 := geod.LatLon{48.857, 2.351} d := p1.DistanceTo(p2).Metre() // 404.3×10³ m m := p1.DistanceTo(p2, 3959).Mile() // 251.2 miles

func (LatLonEllipsoidalVincenty) FinalBearingOn 

func (llv LatLonEllipsoidalVincenty) FinalBearingOn(dest LatLon) Degrees

FinalBearingOn returns the final bearing (review azimuth) having travelled along a geodesic from `llv` to `dest` using the Vincenty inverse solution

Arguments:

dest - destination point

Returns the final bearing in degrees from North (0°..360°) or NaN if failed to converge

Example: p1 := geod.NewLatLonEllipsodialVincenty(50.06632, -5.71475, geod.WGS84()) p2 := geod.LatLon{58.64402, -3.07009} b1 := p1.FinalBearingOn(p2) // 11.2972°

func (LatLonEllipsoidalVincenty) InitialBearingTo 

func (llv LatLonEllipsoidalVincenty) InitialBearingTo(dest LatLon) Degrees

InitialBearingTo returns the initial bearing (forward azimuth) to travel along a geodesic from `llv` to `dest` using the Vincenty inverse solution

Arguments:

dest - destination point

Returns the initial bearing in degrees from North (0°..360°) or NaN if failed to converge

Example: p1 := geod.NewLatLonEllipsodialVincenty(50.06632, -5.71475, geod.WGS84()) p2 := geod.LatLon{58.64402, -3.07009} b1 := p1.InitialBearingTo(p2) // 9.1419°

func (LatLonEllipsoidalVincenty) IntermediatePointTo 

func (llv LatLonEllipsoidalVincenty) IntermediatePointTo(dest LatLon, fraction float64) LatLon

IntermediatePointTo returns the points at the given fraction between `llv` and `dest`.

Arguments:

dest - destination point fraction - Fractions between the two points (0 = `llv`, 1 = `dest`)

Returns the intermediate point.

Example: p1 := geod.NewLatLonEllipsodialVincenty(52.205, 0.119, geod.WGS84()) p2 := geod.LatLon{48.857, 2.351} pInt := p1.IntermediatePointTo(p2, 0.25)

func (LatLonEllipsoidalVincenty) IntermediatePointsTo 

func (llv LatLonEllipsoidalVincenty) IntermediatePointsTo(dest LatLon, fractions []float64) []LatLon

IntermediatePointsTo returns the points at the given fractions between `llv` and `dest`.

Arguments:

dest - destination point fraction - Slice of fractions between the two points (0 = `llv`, 1 = `dest`)

Returns an intermediate point for each fraction

Example: p1 := geod.NewLatLonEllipsodialVincenty(52.205, 0.119, geod.WGS84()) p2 := geod.LatLon{48.857, 2.351} pInt := p1.IntermediatePointsTo(p2, []float64{0.25, 0.5, 0.75})

func (LatLonEllipsoidalVincenty) LatLon 

func (llv LatLonEllipsoidalVincenty) LatLon() LatLon

LatLon converts LatLonEllipsoidalVincenty to LatLon

func (LatLonEllipsoidalVincenty) MidPointTo 

func (llv LatLonEllipsoidalVincenty) MidPointTo(dest LatLon) LatLon

MidPointTo returns the midpoint between `llv` and `dest`.

Argument:

dest - destination point

Returns the middle point

Example: p1 := geod.NewLatLonEllipsodialVincenty(52.205, 0.119, geod.WGS84()) p2 := geod.LatLon{48.857, 2.351} pMid := p1.MidPointTo(p2)

func (LatLonEllipsoidalVincenty) VincentyDirect 

func (llv LatLonEllipsoidalVincenty) VincentyDirect(distance float64, initialBearing Degrees) (LatLon, Degrees)

VincentyDirect - Vincenty direct calculation - calculates the destination point and final bearing given the starting point, distance and initial bearing.

Arguments

distance - Distance along bearing in metres initialBearing - Initial bearing in degrees from North

Returns (destination, finalBearing)

func (LatLonEllipsoidalVincenty) VincentyInverse 

func (llv LatLonEllipsoidalVincenty) VincentyInverse(dest LatLon) (units.Distance, Degrees, Degrees)

VincentyInverse - Vincenty inverse calculation. Calculates the distance, initial and final bearing going from point `llv` to `dest`, using the Vincenty method.

Arguments:

dest - destination point

Returns (distance from `llv` to `dest`, initial bearing in degrees from North, final bearing in degrees from North)

type LatLonPlanar added in v0.0.5 

type LatLonPlanar struct {
	// contains filtered or unexported fields
}

LatLonPlanar represents a point used for calculations on a 2-dimensional plane Longitudes still go -180 to 180 and wrap around and Latitudes go -90 to 90. Works across the antimeridian.

func NewLatLonPlanar added in v0.0.5 

func NewLatLonPlanar(latitude, longitude float64) LatLonPlanar

NewLatLonPlanar creates a new LatLonPlanar struct

func ParseLatLonPlanar added in v0.0.5 

func ParseLatLonPlanar(args ...interface{}) (LatLonPlanar, error)

ParseLatLonPlanar parses a latitude/longitude point from a variety of formats See ParseLatLon for details.

func (LatLonPlanar) DestinationPoint added in v0.0.5 

func (lls LatLonPlanar) DestinationPoint(distance float64, bearing Degrees) LatLon

func (LatLonPlanar) DistanceTo added in v0.0.5 

func (lls LatLonPlanar) DistanceTo(dest LatLon) units.Distance

func (LatLonPlanar) FinalBearingOn added in v0.0.5 

func (lls LatLonPlanar) FinalBearingOn(ll LatLon) Degrees

func (LatLonPlanar) InitialBearingTo added in v0.0.5 

func (lls LatLonPlanar) InitialBearingTo(ll LatLon) Degrees

Returns the initial bearing in Degrees from North (0°..360°)

func (LatLonPlanar) IntermediatePointTo added in v0.0.5 

func (lls LatLonPlanar) IntermediatePointTo(ll LatLon, fraction float64) LatLon

func (LatLonPlanar) IntermediatePointsTo added in v0.0.5 

func (lls LatLonPlanar) IntermediatePointsTo(ll LatLon, fractions []float64) []LatLon

func (LatLonPlanar) LatLon added in v0.0.5 

func (lls LatLonPlanar) LatLon() LatLon

LatLon converts LatLonPlanar to LatLon

func (LatLonPlanar) MidPointTo added in v0.0.5 

func (lls LatLonPlanar) MidPointTo(ll LatLon) LatLon

type LatLonRhumb 

type LatLonRhumb struct {
	// contains filtered or unexported fields
}

LatLonRhumb represents a point used for calculations using a spherical Earth model, along rhumb lines

func NewLatLonRhumb 

func NewLatLonRhumb(latitude, longitude Degrees) LatLonRhumb

NewLatLonRhumb creates a new LatLonRhumb struct

func (LatLonRhumb) DestinationPoint 

func (llr LatLonRhumb) DestinationPoint(distance float64, bearing Degrees) LatLon

DestinationPoint returns the destination point from `lls` having travelled the given distance along a rhumb line on the given bearing.

Arguments:

distance - Distance travelled in metres bearing - Bearing in `Degrees` from North

Returns the destination point.

Example: p1 := geod.NewLatLonRhumb(51.127, 1.338) p2 := p1.DestinationPoint(40300, geod.Degrees(116.7)) // 50.9642°N, 001.8530°E

func (LatLonRhumb) DistanceTo 

func (llr LatLonRhumb) DistanceTo(dest LatLon) units.Distance

DistanceTo returns the distance along a rhumb line from `llr` to `dest`.

Argument:

dest - destination point

Returns the `Distance` between this point and destination point in Distance units.

Examples: p1 := geod.NewLatLonRhumb(51.127, 1.338) p2 := geod.NewLatLonRhumb(50.964, 1.853) d := p1.DistanceTo(p2).Km() // 40.31 km

func (LatLonRhumb) FinalBearingOn 

func (llr LatLonRhumb) FinalBearingOn(dest LatLon) Degrees

FinalBearingOn returns the bearing from `lls` to `dest`. In the case of rhumb lines the bearing is constant, so this is the same as the initial bearing.

Argument:

dest - destination point

Returns the rhumb bearing in `Degrees` from North (0°..360°)

Example: p1 := geod.NewLatLonRhumb(51.127, 1.338) p2 := geod.NewLatLonRhumb(50.964, 1.853) b1 := p1.FinalBearingOn(p2) // 116.7°

func (LatLonRhumb) InitialBearingTo 

func (llr LatLonRhumb) InitialBearingTo(dest LatLon) Degrees

InitialBearingTo returns the bearing from `lls` to `dest`. In the case of rhumb lines the bearing is constant, so this is the same as the final bearing.

Argument:

dest - destination point

Returns the rhumb bearing in `Degrees` from North (0°..360°)

Example: p1 := geod.NewLatLonRhumb(51.127, 1.338) p2 := geod.NewLatLonRhumb(50.964, 1.853) b1 := p1.InitialBearingTo(p2) // 116.7°

func (LatLonRhumb) IntermediatePointTo 

func (llr LatLonRhumb) IntermediatePointTo(dest LatLon, fraction float64) LatLon

IntermediatePointTo returns the point at the given fraction between `lls` and `dest` along a rhumb line

Arguments:

dest - destination point fraction - Fraction between the two points (0 = `lls`, 1 = `dest`)

Returns the intermediate point.

Example: p1 := geod.NewLatLonRhumb(51.127, 1.338) p2 := geod.NewLatLonRhumb(50.964, 1.853) pMid := p1.IntermediatePointTo(p2, 0.25) // 51.08625°N, 001.46692°E

func (LatLonRhumb) IntermediatePointsTo 

func (llr LatLonRhumb) IntermediatePointsTo(dest LatLon, fractions []float64) []LatLon

IntermediatePointsTo returns the points at the given fractions between `llr` and `dest`.

Arguments:

dest - destination point fraction - Slice of fractions between the two points (0 = `llr`, 1 = `dest`)

Returns an intermediate point for each fraction

Example: p1 := geod.NewLatLonRhumb(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} pInt := p1.IntermediatePointsTo(p2, []float64{0.25, 0.5, 0.75})

func (LatLonRhumb) LatLon 

func (llr LatLonRhumb) LatLon() LatLon

LatLon converts LatLonRhumb to LatLon

func (LatLonRhumb) MidPointTo 

func (llr LatLonRhumb) MidPointTo(dest LatLon) LatLon

MidPointTo returns the loxodromic midpoint (along a rhumb line) between `llr` and `dest`.

Argument:

dest - destination point

Returns the middle point

Example: p1 := geod.NewLatLonRhumb(51.127, 1.338) p2 := geod.NewLatLonRhumb(50.964, 1.853) pMid := p1.MidPointTo(p2) // 51.0455°N, 001.5957°E

type LatLonSpherical 

type LatLonSpherical struct {
	// contains filtered or unexported fields
}

LatLonSpherical represents a point used for calculations using a spherical Earth model, along great circles

func NewLatLonSpherical 

func NewLatLonSpherical(latitude, longitude float64) LatLonSpherical

NewLatLonSpherical creates a new LatLonSpherical struct

func ParseLatLonSpherical 

func ParseLatLonSpherical(args ...interface{}) (LatLonSpherical, error)

ParseLatLonSpherical parses a latitude/longitude point from a variety of formats See ParseLatLon for details.

func (LatLonSpherical) DestinationPoint 

func (lls LatLonSpherical) DestinationPoint(distance float64, bearing Degrees) LatLon

DestinationPoint returns the destination point from `lls` having travelled the given distance on the given initial bearing (bearing normally varies around path followed).

Arguments:

distance - Distance travelled in metres bearing - Initial bearing in `Degrees` from North

Returns the destination point.

Example: p1 := geod.NewLatLonSpherical(51.47788, -0.00147) p2 := p1.DestinationPoint(7794, geod.Degrees(300.7)) // 51.5136°N, 000.0983°W

func (LatLonSpherical) DistanceTo 

func (lls LatLonSpherical) DistanceTo(dest LatLon) units.Distance

DistanceTo returns the distance along the surface of the earth from `lls` to `dest`.

Uses haversine formula: a = sin²(Δφ/2) + cosφ1·cosφ2 · sin²(Δλ/2); d = 2 · atan2(√a, √(a-1)). Use SetEarthRadius() to change the default value.

Argument:

dest - destination point

Returns the `Distance` between this point and destination point in Distance units.

Examples: p1 := geod.NewLatLonSpherical(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} d := p1.DistanceTo(p2).Metres() // 404.3×10³ m m := p1.DistanceTo(p2, 3959).Miles() // 251.2 miles

func (LatLonSpherical) FinalBearingOn 

func (lls LatLonSpherical) FinalBearingOn(dest LatLon) Degrees

FinalBearingOn returns the final bearing arriving at `dest` from `lls`; the final bearing will differ from the initial bearing by varying degrees according to distance and latitude.

Argument:

dest - destination point

Returns the initial bearing in `Degrees` from North (0°..360°)

Example: p1 := geod.NewLatLonSpherical(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} b1 := p1.FinalBearingOn(p2) // 157.9°

func (LatLonSpherical) InitialBearingTo 

func (lls LatLonSpherical) InitialBearingTo(dest LatLon) Degrees

InitialBearingTo returns the initial bearing from `lls` to `dest`.

Argument:

dest - destination point

Returns the initial bearing in `Degrees` from North (0°..360°)

Example: p1 := geod.NewLatLonSpherical(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} b1 := p1.InitialBearingTo(p2) // 156.2°

func (LatLonSpherical) IntermediatePointTo 

func (lls LatLonSpherical) IntermediatePointTo(dest LatLon, fraction float64) LatLon

IntermediatePointTo returns the point at the given fraction between `lls` and `dest`.

Arguments:

dest - destination point fraction - Fraction between the two points (0 = `lls`, 1 = `dest`)

Returns the intermediate point.

Example: p1 := geod.NewLatLonSpherical(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} pInt := p1.IntermediatePointTo(p2, 0.25) // 51.3721°N, 000.7073°E

func (LatLonSpherical) IntermediatePointsTo 

func (lls LatLonSpherical) IntermediatePointsTo(dest LatLon, fractions []float64) []LatLon

IntermediatePointsTo returns the points at the given fractions between `lls` and `dest`.

Arguments:

dest - destination point fraction - Slice of fractions between the two points (0 = `lls`, 1 = `dest`)

Returns an intermediate point for each fraction

Example: p1 := geod.NewLatLonSpherical(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} pInt := p1.IntermediatePointsTo(p2, []float64{0.25, 0.5, 0.75})

func (LatLonSpherical) Intersection 

func (lls LatLonSpherical) Intersection(bearing1 Degrees, ll2 LatLon, bearing2 Degrees) LatLon

Intersection returns the point of intersection of two paths defined by point and bearing.

Arguments:

bearing1 - Initial bearing in `Degrees` from North from `lls` lls2 - Second point bearing2 - Initial bearing in `Degrees` from North from `lls2`

Returns the point of intersection of the 2 paths. If the intersection point cannot be calculated (e.g. infinite intersections) the returned point has NaN as Latitude and Longitude.

Example: p1 := geod.NewLatLonSpherical(51.8853, 0.2545) brng1 := geod.Degrees(108.547) p2 := geod.LatLon{49.0034, 2.5735} brng2 := geod.Degrees(32.435) pInt := p1.Intersection(brng1, p2, brng2) // 50.9078°N, 004.5084°E

func (LatLonSpherical) LatLon 

func (lls LatLonSpherical) LatLon() LatLon

LatLon converts LatLonSpherical to LatLon

func (LatLonSpherical) MidPointTo 

func (lls LatLonSpherical) MidPointTo(dest LatLon) LatLon

MidPointTo returns the midpoint between `lls` and `dest`

Argument:

dest - destination point

Returns the middle point

Example: p1 := geod.NewLatLonSpherical(52.205, 0.119) p2 := geod.LatLon{48.857, 2.351} pMid := p1.MidPointTo(p2) // 50.5363°N, 001.2746°E

type MercatorPoint added in v0.0.5 

type MercatorPoint struct {
	X float64
	Y float64
}

func (MercatorPoint) LatLon added in v0.0.5 

func (mp MercatorPoint) LatLon() LatLon

MercatorPoint convert a point in Mercator projection the a Latitude/Longitude. The Mercator coordinates must be in the [0..1] range, so divide by the horizontal/vertical resolution.

type Model 

type Model interface {
	DistanceTo(ll LatLon) units.Distance
	InitialBearingTo(ll LatLon) Degrees
	FinalBearingOn(ll LatLon) Degrees
	DestinationPoint(distance float64, bearing Degrees) LatLon
	MidPointTo(ll LatLon) LatLon
	IntermediatePointTo(ll LatLon, fraction float64) LatLon
	IntermediatePointsTo(ll LatLon, fractions []float64) []LatLon
	LatLon() LatLon
}

Model defines the Earth model used for calculations. The following models are implemented: 

geod.SphericalModel  - spherical Earth, along great circles
geod.RhumbModel      - spherical Earth, along rhumb lines
geod.VincentyModel   - ellipsoid Earth, high accuracy, slower than SphericalModel

func PlanarModel added in v0.0.5 

func PlanarModel(ll LatLon, modelArgs ...interface{}) Model

PlanarModel returns a `Model` that wraps geodesy calculations using Planar model (2-dimensional plane) Only suitable for short distances.

func RhumbModel 

func RhumbModel(ll LatLon, modelArgs ...interface{}) Model

RhumbModel returns a `Model` that wraps geodesy calculations using spherical Earth model along rhumb lines

func SphericalModel 

func SphericalModel(ll LatLon, modelArgs ...interface{}) Model

SphericalModel returns a `Model` that wraps geodesy calculations using spherical Earth model along great circles

func VincentyModel 

func VincentyModel(ll LatLon, modelArgs ...interface{}) Model

VincentyModel returns a `Model` that wraps geodesy calculations using the Vincenty method on an ellipsoidal Earth model

type Vector3D 

type Vector3D struct {
	X, Y, Z float64
}

Vector3D represents a 3 dimensional vector

func (Vector3D) AngleTo 

func (v Vector3D) AngleTo(other Vector3D, n *Vector3D) float64

AngleTo calculates the angle between the vector and the `other` vector atan2(|p₁×p₂|, p₁·p₂) or if (extra-planar) `n` is not nil then atan2(n·p₁×p₂, p₁·p₂).

Arguments:

`other` - Vector whose angle is to be determined from the `v` vector `n` - Plane normal: if not nil, angle is signed +ve if `v` is clockwise looking along `n`, -ve in opposite direction

Returns the angle (in radians) between the `v` vector and the `other` vector in range 0..π if n is nil, or range -π..+π if n is not nil.

func (Vector3D) Copy 

func (v Vector3D) Copy() Vector3D

Copy returns an identical copy of the vector

func (Vector3D) Cross 

func (v Vector3D) Cross(other Vector3D) Vector3D

Cross multiplies the vector by the `other` vector using cross (vector) product, returns the resulting vector

func (Vector3D) DividedBy 

func (v Vector3D) DividedBy(f float64) Vector3D

DividedBy divides the vector by a scalar value Returns a copy of the divided vector.

func (Vector3D) Dot 

func (v Vector3D) Dot(other Vector3D) float64

Dot multiplies the vector by the `other` vector using dot (scalar) product

func (Vector3D) Equals 

func (v Vector3D) Equals(other Vector3D) bool

Equals returns true if the vector equals the `other` vector, false otherwise

func (Vector3D) Length 

func (v Vector3D) Length() float64

Length returns the length (magnitude or norm) of the vector.

func (Vector3D) Minus 

func (v Vector3D) Minus(other Vector3D) Vector3D

Minus subtracts the `other` vector from the vector Returns a copy of the resulting vector.

func (Vector3D) Negate 

func (v Vector3D) Negate() Vector3D

Negate negates a vector to point in the opposite direction, returns the resulting vector

func (Vector3D) Plus 

func (v Vector3D) Plus(other Vector3D) Vector3D

Plus adds the `other` vector to the vector Returns a copy of the resulting vector.

func (Vector3D) RotateAround 

func (v Vector3D) RotateAround(axis Vector3D, angle Degrees) Vector3D

RotateAround rotates the vector around an axis by a specified angle

Arguments:

`axis` - The axis being rotated around. `angle` - The angle of rotation (in degrees)

Returns the rotated vector

func (Vector3D) Str 

func (v Vector3D) Str() string

Str returns a string representation of the vector, rounded to 3 decimal points

func (Vector3D) Times 

func (v Vector3D) Times(f float64) Vector3D

Times multiplies the vector by a scalar value Returns a copy of the multiplied vector.

func (Vector3D) Unit 

func (v Vector3D) Unit() Vector3D

Unit normalizes a vector to its unit vector, returns the resulting vector

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