OpenSpace.GridProjection

Enables transformation from WGS84 to British National Grid and from British National Grid to WGS84.

Example

var gridProjection = new OpenSpace.GridProjection();
var lonlat = new OpenLayers.LonLat(-0.15567, 54.4544);
var mapPoint = gridProjection.getMapPointFromLonLat(lonlat);

Summary

OpenSpace.GridProjection	Enables transformation from WGS84 to British National Grid and from British National Grid to WGS84.
Constructor
OpenSpace.GridProjection	Create a new OpenSpace.GridProjection instance
Functions
getMapPointFromLonLat	Convert an WGS84 point into a OSGB36 grid point
getLonLatFromMapPoint	Convert a OSGB36 grid point into a WGS84 lon lat point
os_arc	Internal conversion method
geog2Grid	Internal conversion method
convert_89_36	Convert an ETRS89 point into a OSGB36 point
E_N_to_LonLat	Convert an ETRS89 point into a WGS84 point
initialLat	Internal conversion method
marc	Internal conversion method to Compute meridional arc.
convert_36_89	Convert an OSGB36 point into an ETRS89 point
bilinear	Internal interpolation method.
projectForward	Given an object with x and y properties in EPSG:4326, modify the x,y properties on the object to be the OSGB EPSG:27700 projected coordinates.
projectInverse	Given an object with x and y properties in Spherical Mercator, modify the x,y properties on the object to be the unprojected coordinates.

Constructor

OpenSpace.GridProjection

Create a new OpenSpace.GridProjection instance

Parameters

Returns

An instance of OpenSpace.GridProjection

Functions

getMapPointFromLonLat

getMapPointFromLonLat: function( pt_LonLat )

Convert an WGS84 point into a OSGB36 grid point

Parameters

pt_LonLat

{<OpenLayers.LonLat}> The point to convert

Returns

{OpenSpace.MapPoint} The point converted into OSGB36 British National Grid

getLonLatFromMapPoint

getLonLatFromMapPoint: function( pt_OSGB36 )

Convert a OSGB36 grid point into a WGS84 lon lat point

Parameters

pt_OSGB36

{OpenSpace.MapPoint} The point to convert

Returns

{<OpenLayers.LonLat>} The point converted into WGS84 Longitude Latitude

os_arc

os_arc: function( k3,
k4 )

Internal conversion method

Parameters

k3	{Float}
k4	{Float}

Returns

{Float}

geog2Grid

geog2Grid: function( pt_LonLat )

Internal conversion method

Parameters

pt_LonLat

{<OpenLayers.LonLat}> The point to convert

Returns

{<OpenLayers.LonLat>} The point converted

convert_89_36

convert_89_36: function( pt_ETRS89 )

Convert an ETRS89 point into a OSGB36 point

Parameters

pt_ETRS89

{<OpenLayers.LonLat}> The point to convert

Returns

{OpenSpace.MapPoint} The point converted into British National Grid

E_N_to_LonLat

E_N_to_LonLat: function( pt_ETRS89 )

Convert an ETRS89 point into a WGS84 point

Parameters

pt_ETRS89

{<OpenLayers.LonLat}> The point to convert

Returns

{<OpenLayers.LonLat>} The point converted into WGS84

initialLat

initialLat: function( North,
n0,
afo,
PHI0,
n,
bfo )

Internal conversion method

Parameters

Returns

{Float}

marc

marc: function( bf0,
n,
PHI0,
PHI )

Internal conversion method to Compute meridional arc.

Parameters

Returns

{Float}

convert_36_89

convert_36_89: function( pt_OSGB36 )

Convert an OSGB36 point into an ETRS89 point

Parameters

pt_OSGB36

{<OpenLayers.LonLat}> The point to convert

Returns

{<OpenLayers.LonLat>} The point converted into ETRS89

bilinear

bilinear: function( /* double[] * /y,
/* double */ x1l,
/* double */ x1u,
/* double */ x2l,
/* double */ x2u,
/* double */ x1,
/* double */ x2 )

Internal interpolation method.

Parameters

Returns

{Float}

projectForward

projectForward: function( point )

Given an object with x and y properties in EPSG:4326, modify the x,y properties on the object to be the OSGB EPSG:27700 projected coordinates.

Parameters

point

{Object} An object with x and y properties.

Returns

{Object} The point, with the x and y properties transformed to OSGB

projectInverse

projectInverse: function( point )

Given an object with x and y properties in Spherical Mercator, modify the x,y properties on the object to be the unprojected coordinates.

Parameters

point

{Object} An object with x and y properties.

Returns

{Object} The point, with the x and y properties transformed from spherical mercator to unprojected coordinates..