proj

README

This is based on https://github.com/pebbe/proj and modified for static linking

Documentation

Index

• Constants
• func DegToRad(deg float64) float64
• func RadToDeg(rad float64) float64
• type Context
  • func NewContext() *Context
  • func (ctx *Context) Close()
  • func (ctx *Context) Create(definition string) (*PJ, error)
• type Direction
• type LibInfo
  • func Info() LibInfo
• type PJ
  • func (p *PJ) Close()
  • func (p *PJ) Dist(u1, v1, u2, v2 float64) (float64, error)
  • func (p *PJ) Dist3(u1, v1, w1, u2, v2, w2 float64) (float64, error)
  • func (p *PJ) Info() (ProjInfo, error)
  • func (p *PJ) Trans(direction Direction, u1, v1, w1, t1 float64) (u2, v2, w2, t2 float64, err error)
  • func (p *PJ) TransSlice(direction Direction, u1, v1, w1, t1 []float64) (u2, v2, w2, t2 []float64, err error)
• type ProjInfo

Constants

const (
	Fwd   = Direction(C.PJ_FWD)   // Forward transformation
	Ident = Direction(C.PJ_IDENT) // Do nothing
	Inv   = Direction(C.PJ_INV)   // Inverse transformation
)

Functions

func DegToRad

func DegToRad(deg float64) float64

Convert degrees to radians

func RadToDeg

func RadToDeg(rad float64) float64

Convert radians to degrees

Types

type Context

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

func NewContext

func NewContext() *Context

Create a context

func (*Context) Close

func (ctx *Context) Close()

Close a context

func (*Context) Create

func (ctx *Context) Create(definition string) (*PJ, error)

Create a transformation object

type Direction

type Direction C.PJ_DIRECTION

The direction of a transformation

type LibInfo

type LibInfo struct {
	Major      int    // Major version number.
	Minor      int    // Minor version number.
	Patch      int    // Patch level of release.
	Release    string // Release info. Version number and release date, e.g. “Rel. 4.9.3, 15 August 2016”.
	Version    string // Text representation of the full version number, e.g. “4.9.3”.
	Searchpath string // Search path for PROJ. List of directories separated by semicolons (Windows) or colons (non-Windows).
}

func Info

func Info() LibInfo

Get information about the current instance of the PROJ library

type PJ

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

A projection object

func (*PJ) Close

func (p *PJ) Close()

Close a transformation object

func (*PJ) Dist

func (p *PJ) Dist(u1, v1, u2, v2 float64) (float64, error)

Calculate geodesic distance between two points in geodetic coordinates

The calculated distance is between the two points located on the ellipsoid

func (*PJ) Dist3

func (p *PJ) Dist3(u1, v1, w1, u2, v2, w2 float64) (float64, error)

Calculate geodesic distance between two points in geodetic coordinates

Similar to Dist() but also takes the height above the ellipsoid into account

func (*PJ) Info

func (p *PJ) Info() (ProjInfo, error)

Get information about the transformation object

func (*PJ) Trans

func (p *PJ) Trans(direction Direction, u1, v1, w1, t1 float64) (u2, v2, w2, t2 float64, err error)

Transform a single coordinate

func (*PJ) TransSlice

func (p *PJ) TransSlice(direction Direction, u1, v1, w1, t1 []float64) (u2, v2, w2, t2 []float64, err error)

Transform a series of coordinates, where the individual coordinate dimension may be represented by a slice that is either

1. fully populated

2. nil and/or a length of zero, which will be treated as a fully populated slice of zeroes

3. of length one, i.e. a constant, which will be treated as a fully populated slice of that constant value

Note: if an input coordinate is constant, but the output coordinate varies, you need to supply a fully populated slice as input

type ProjInfo

type ProjInfo struct {
	ID          string  // Short ID of the operation the PJ object is based on, that is, what comes afther the +proj= in a proj-string, e.g. “merc”.
	Description string  // Long describes of the operation the PJ object is based on, e.g. “Mercator Cyl, Sph&Ell lat_ts=”.
	Definition  string  // The proj-string that was used to create the PJ object with, e.g. “+proj=merc +lat_0=24 +lon_0=53 +ellps=WGS84”.
	HasInverse  bool    // True if an inverse mapping of the defined operation exists,
	Accuracy    float64 // Expected accuracy of the transformation. -1 if unknown.
}