// Transform a BMN coordinate value to a WGS84 based latitude and longitude coordinate. Function returns
// EINVAL, if the meridian stripe of the bmn-coordinate is not set
func BMNToWGS84LatLong(bmncoord *BMNCoord) (*cartconvert.PolarCoord, os.Error) {
var long0, fe float64
switch bmncoord.Meridian {
case BMNM28:
long0 = 10.0 + 20.0/60.0
fe = 150000
case BMNM31:
long0 = 13.0 + 20.0/60.0
fe = 450000
case BMNM34:
long0 = 16.0 + 20.0/60.0
fe = 750000
default:
return nil, os.EINVAL
}
gc := cartconvert.InverseTransverseMercator(
&cartconvert.GeoPoint{Y: bmncoord.Height, X: bmncoord.Right, El: bmncoord.el},
0,
long0,
1,
fe,
-5000000)
cart := cartconvert.PolarToCartesian(gc)
pt := cartconvert.HelmertWGS84ToMGI.InverseTransform(&cartconvert.Point3D{X: cart.X, Y: cart.Y, Z: cart.Z})
return cartconvert.CartesianToPolar(&cartconvert.CartPoint{X: pt.X, Y: pt.Y, Z: pt.Z, El: cartconvert.WGS84Ellipsoid}), nil
}
// Transform a Swiss coordinate value to a GRS80 based latitude and longitude coordinate. Function returns
// EINVAL, if the swiss coordinate type is not one of LV03 or LV95
func SwissCoordToGRS80LatLong(coord *SwissCoord) (*cartconvert.PolarCoord, os.Error) {
var fn, fe float64
switch coord.CoordType {
case LV03:
fe = 600000
fn = 200000
case LV95:
fe = -2600000
fn = -1200000
default:
return nil, os.EINVAL
}
gc := cartconvert.InverseTransverseMercator(
&cartconvert.GeoPoint{Y: coord.Northing, X: coord.Easting, El: coord.el},
46.952406, // lat0
7.439583, // long0
1,
fe, // fe
fn) // fn
cart := cartconvert.PolarToCartesian(gc)
// According to literature, the Granit87 parameters shall not be used in favour of
// higher accuracy of the following shift values
// pt := cartconvert.HelmertLV03ToWGS84Granit87.Transform(&cartconvert.Point3D{X: cart.X, Y: cart.Y, Z: cart.Z})
pt := &cartconvert.Point3D{X: cart.X + 674.374, Y: cart.Y + 15.056, Z: cart.Z + 405.346}
return cartconvert.CartesianToPolar(&cartconvert.CartPoint{X: pt.X, Y: pt.Y, Z: pt.Z, El: cartconvert.GRS80Ellipsoid}), nil
}
// Transform a latitude / longitude coordinate datum into a BMN coordinate. Function returns
// EINVAL, if the meridian stripe of the bmn-coordinate is not set.
//
// Important: The reference ellipsoid of the originating coordinate system will be assumed
// to be the WGS84Ellipsoid and will be set thereupon, regardless of the actually set reference ellipsoid.
func WGS84LatLongToBMN(gc *cartconvert.PolarCoord, meridian BMNMeridian) (*BMNCoord, os.Error) {
var long0, fe float64
// This sets the Ellipsoid to WGS84, regardless of the actual value set
gc.El = cartconvert.WGS84Ellipsoid
cart := cartconvert.PolarToCartesian(gc)
pt := cartconvert.HelmertWGS84ToMGI.Transform(&cartconvert.Point3D{X: cart.X, Y: cart.Y, Z: cart.Z})
polar := cartconvert.CartesianToPolar(&cartconvert.CartPoint{X: pt.X, Y: pt.Y, Z: pt.Z, El: cartconvert.Bessel1841MGIEllipsoid})
// Determine meridian stripe based on longitude
if meridian == BMNZoneDet {
switch {
case 11.0+0.5/6*10 >= polar.Longitude && polar.Longitude >= 8.0+0.5/6*10:
meridian = BMNM28
case 14.0+0.5/6*10 >= polar.Longitude && polar.Longitude >= 11.0+0.5/6*10:
meridian = BMNM31
case 17.0+0.5/6*10 >= polar.Longitude && polar.Longitude >= 14.0+0.5/6*10:
meridian = BMNM34
}
}
switch meridian {
case BMNM28:
long0 = 10.0 + 20.0/60.0
fe = 150000
case BMNM31:
long0 = 13.0 + 20.0/60.0
fe = 450000
case BMNM34:
long0 = 16.0 + 20.0/60.0
fe = 750000
default:
return nil, os.EINVAL
}
gp := cartconvert.DirectTransverseMercator(
polar,
0,
long0,
1,
fe,
-5000000)
return &BMNCoord{Meridian: meridian, Height: gp.Y, Right: gp.X, el: gp.El}, nil
}
// Convert an OSGB36 coordinate value to a WGS84 based latitude and longitude coordinate.
//
// Important: A OSGB36 datum like NN11 will be internally expanded to NN1500015000 to point to the middle of the zone.
// For the point at NN1000010000 it is necessary to fully qualify northing and easting.
//
// Plain grid zone specifiers will NOT be shifted towards the middle of the square.
func OSGB36ToWGS84LatLong(coord *OSGB36Coord) *cartconvert.PolarCoord {
easting, northing := OSGB36ZoneToRefCoords(coord)
gc := cartconvert.InverseTransverseMercator(
&cartconvert.GeoPoint{Y: float64(northing), X: float64(easting), El: coord.el},
49,
-2,
0.9996012717,
400000,
-100000)
cart := cartconvert.PolarToCartesian(gc)
pt := cartconvert.HelmertWGS84ToOSGB36.InverseTransform(&cartconvert.Point3D{X: cart.X, Y: cart.Y, Z: cart.Z})
return cartconvert.CartesianToPolar(&cartconvert.CartPoint{X: pt.X, Y: pt.Y, Z: pt.Z, El: cartconvert.WGS84Ellipsoid})
}
// Transform a latitude / longitude coordinate datum into a OSGB36 coordinate.
//
// Important: The reference ellipsoid of the originating coordinate system will be assumed
// to be the WGS84Ellipsoid and will be set thereupon, regardless of the actually set reference ellipsoid.
func WGS84LatLongToOSGB36(gc *cartconvert.PolarCoord) (*OSGB36Coord, os.Error) {
// This sets the Ellipsoid to WGS84, regardless of the actual value set
gc.El = cartconvert.WGS84Ellipsoid
cart := cartconvert.PolarToCartesian(gc)
pt := cartconvert.HelmertWGS84ToOSGB36.Transform(&cartconvert.Point3D{X: cart.X, Y: cart.Y, Z: cart.Z})
polar := cartconvert.CartesianToPolar(&cartconvert.CartPoint{X: pt.X, Y: pt.Y, Z: pt.Z, El: cartconvert.Airy1830Ellipsoid})
gp := cartconvert.DirectTransverseMercator(
polar,
49,
-2,
0.9996012717,
400000,
-100000)
return GridRefNumToLet(uint(gp.X+0.5), uint(gp.Y+0.5), 0, OSGB36_Max)
}
// Transform a latitude / longitude coordinate datum into a Swiss coordinate. Function returns
// EINVAL, if the coordinate type is not set.
//
// Important: The reference ellipsoid of the originating coordinate system will be assumed
// to be the GRS80Ellipsoid and will be set thereupon, regardless of the actually set reference ellipsoid.
func GRS80LatLongToSwissCoord(gc *cartconvert.PolarCoord, coordType SwissCoordType) (*SwissCoord, os.Error) {
var fn, fe float64
// This sets the Ellipsoid to GRS80, regardless of the actual value set
gc.El = cartconvert.GRS80Ellipsoid
cart := cartconvert.PolarToCartesian(gc)
// According to literature, the Granit87 parameters shall not be used in favour of
// higher accuracy of the following shift values
// pt := cartconvert.HelmertWGS84ToMGI.Transform(&cartconvert.Point3D{X: cart.X, Y: cart.Y, Z: cart.Z})
pt := &cartconvert.Point3D{X: cart.X - 674.374, Y: cart.Y - 15.056, Z: cart.Z - 405.346}
polar := cartconvert.CartesianToPolar(&cartconvert.CartPoint{X: pt.X, Y: pt.Y, Z: pt.Z, El: cartconvert.Bessel1841Ellipsoid})
switch coordType {
case LV03:
fe = 600000
fn = 200000
case LV95:
fe = -2600000
fn = -1200000
default:
return nil, os.EINVAL
}
gp := cartconvert.DirectTransverseMercator(
polar,
46.952406, // lat0
7.439583, // long0
1,
fe, // fe
fn) // fn
return &SwissCoord{CoordType: coordType, Northing: gp.Y, Easting: gp.X, el: gp.El}, nil
}