Module epsglide.src

Unit Objects

class Unit(ctypes.Structure)

Represents a Unit structure in C code.

Attributes:

  • ratio float - The ratio value of the unit.

Prime Objects

class Prime(ctypes.Structure)

Represents a Prime structure in C code.

Attributes:

  • longitude float - The longitude value of the prime meridian.

Ellipsoid Objects

class Ellipsoid(ctypes.Structure)

Represents an Ellipsoid structure in C code.

Attributes:

  • a float - The semi-major axis of the ellipsoid.
  • b float - The semi-minor axis of the ellipsoid.
  • e float - The eccentricity of the ellipsoid.
  • f float - The flattening of the ellipsoid.

Datum Objects

class Datum(ctypes.Structure)

Represents a Datum structure in C code.

Attributes:

  • ellipsoid Ellipsoid - The ellipsoid associated with the datum.
  • prime Prime - The prime meridian associated with the datum.
  • ds float - The scale difference parameter.
  • dx float - The X translation parameter.
  • dy float - The Y translation parameter.
  • dz float - The Z translation parameter.
  • rx float - The X rotation parameter.
  • ry float - The Y rotation parameter.
  • rz float - The Z rotation parameter.

Crs Objects

class Crs(ctypes.Structure)

Represents a Crs structure in C code.

Attributes:

  • datum Datum - The datum associated with the coordinate reference system.
  • lambda0 float - The longitude of the point from which the values of both the geographical coordinates on the ellipsoid and the grid coordinates on the projection are deemed to increment or decrement for computational purposes. Alternatively it may be considered as the longitude of the point which in the absence of application of false coordinates has grid coordinates of (0,0). Sometimes known as “central meridian” (CM).
  • phi0 float - The latitude of the point from which the values of both the geographical coordinates on the ellipsoid and the grid coordinates on the projection are deemed to increment or decrement for computational purposes. Alternatively it may be considered as the latitude of the point which in the absence of application of false coordinates has grid coordinates of (0,0).
  • phi1 float - for a conic projection with two standard parallels, this is the latitude of one of the parallels of intersection of the cone with the ellipsoid. It is normally but not necessarily that nearest to the pole. Scale is true along this parallel.
  • phi2 float - for a conic projection with two standard parallels, this is the latitude of one of the parallels at which the cone intersects with the ellipsoid. It is normally but not necessarily that nearest to the equator. Scale is true along this parallel.
  • k0 float - the factor by which the map grid is reduced or enlarged during the projection process, defined by its value at the natural origin.
  • x0 float - since the natural origin may be at or near the centre of the projection and under normal coordinate circumstances would thus give rise to negative coordinates over parts of the mapped area, this origin is usually given false coordinates which are large enough to avoid this inconvenience. The False Easting, FE, is the value assigned to the abscissa (east or west) axis of the projection grid at the natural origin.
  • y0 float - since the natural origin may be at or near the centre of the projection and under normal coordinate circumstances would thus give rise to negative coordinates over parts of the mapped area, this origin is usually given false coordinates which are large enough to avoid this inconvenience. The False Northing, FN, is the value assigned to the ordinate (north or south) axis of the projection grid at the natural origin.
  • azimut float - the azimuthal direction (north zero, east of north being positive) of the great circle which is the centre line of an oblique projection. The azimuth is given at the projection centre.