geosoft.gxpy.coordinate_system

Coodinate systems

Classes:
Coordinate_system:

define a coordinate system

Coordinate_translate:

translate coordinates between coordinate systems

Wkt:

well-know coordinate system for ESRI interoperability

Coordinate systems describe how cartesian coordinates are located ralative to the Earth. Cartesian coordinates are right-handed (x, y, z) spatial ordinates that describe locations within a coordinate system frame of reference. For coordinates relative to a horizontal plane, positive z is up, usually equivalent to elevation relative to a vertical datum.

Coordinate systems can be oriented in three dimensions using an orientation definition, which defines an (x0, y0, z0) origin and rotation (rx, ry, rz) around the X, Y and then Z axis relative to a base coordinate system.

Base coordinate systems are usually defined by “well-known” coordinate system projections on a datum of the earth.

Coordinate System Name

A coordinate system will also have a descriptive name that identifies the base system with a datum and “well-known” map projection description, plus optional orientation and vertical reference datum if defined. Orientation parameters are enclosed in <> that define <x0, y0, z0, rx, ry, rz> (eg. <400000, 6200000,0,0,-90,0>). If a vertical reference datum is defined it will appear as a string in square brackets, for example [CGVD28].

Example coordinate system names:

"NAD83 / UTM zone 15N"
"NAD83 / UTM zone 15N <450000,6250000,0,0,0,-25>" # oriented system, rotated -25 degrees
"NAD83 / UTM zone 15N [NAVD88]"
"NAD83 / UTM zone 15N <450000,6250000,0,0,0,-25> [NAVD88]"

The descriptive name for “well-known” coordinate systems is sufficient to describe the coordinate system from the EPSG Geodetic Registry. To fully locate ad-hoc coordinates you will need the parameters defined in the GXF stings. See Coordinate_system.gxf.

Constants:
NAME:

None

NAME_HCS:

gxapi.IPJ_NAME_PCS

NAME_PROJECTION:

gxapi.IPJ_NAME_PROJECTION

NAME_METHOD:

gxapi.IPJ_NAME_METHOD

NAME_DATUM:

gxapi.IPJ_NAME_DATUM

NAME_ELLIPSOID:

gxapi.IPJ_NAME_ELLIPSOID

NAME_LDATUM:

gxapi.IPJ_NAME_LDATUM

NAME_UNIT:

gxapi.IPJ_NAME_UNIT_ABBR

NAME_UNIT_FULL:

gxapi.IPJ_NAME_UNIT_FULL

NAME_TYPE:

gxapi.IPJ_NAME_TYPE

NAME_LLDATUM:

gxapi.IPJ_NAME_LLDATUM

NAME_METHOD_PARMS:

gxapi.IPJ_NAME_METHOD_PARMS

NAME_METHOD_LABEL:

gxapi.IPJ_NAME_METHOD_LABEL

NAME_DATUM_PARMS:

gxapi.IPJ_NAME_DATUM_PARMS

NAME_LDATUM_PARMS:

gxapi.IPJ_NAME_LDATUM_PARMS

NAME_GEOID:

gxapi.IPJ_NAME_GEOID

NAME_LDATUMDESCRIPTION:

gxapi.IPJ_NAME_LDATUMDESCRIPTION

NAME_METHOD_PARMS_NATIVE:

gxapi.IPJ_NAME_METHOD_PARMS_NATIVE

NAME_ORIENTATION:

gxapi.IPJ_NAME_ORIENTATION_PARMS

NAME_VCS:

-1

NAME_HCS_VCS:

-2

LIST_COORDINATESYSTEM:

gxapi.IPJ_PARM_LST_COORDINATESYSTEM

LIST_DATUM:

gxapi.IPJ_PARM_LST_DATUM

LIST_PROJECTION:

gxapi.IPJ_PARM_LST_PROJECTION

LIST_UNITS:

gxapi.IPJ_PARM_LST_UNITS

LIST_UNITSDESCRIPTION:

gxapi.IPJ_PARM_LST_UNITSDESCRIPTION

LIST_LOCALDATUMDESCRIPTION:

gxapi.IPJ_PARM_LST_LOCALDATUMDESCRIPTION

LIST_LOCALDATUMNAME:

gxapi.IPJ_PARM_LST_LOCALDATUMNAME

PARM_DATUM:

‘datum’

PARM_PROJECTION:

‘transform’

PARM_UNITS:

‘units’

PARM_LOCAL_DATUM:

‘datumtrf’

See also

geosoft.gxapi.GXIPJ

Note

Regression tests provide usage examples: tests

Functions

_extract(s, frame)

_t(s)

_unknown(name)

find_key(wkt, k)

Find a key in the wkt, return it's name and items.

hcs_orient_vcs_from_name(name)

Split a full coordinate system name into its components.

is_known(coordinate_system)

Return True if this is a known coordinate system

list_from_wktsrs(wkt)

Return a list from a wkt spatial reference string.

name_from_hcs_orient_vcs(hcs[, orient, vcs])

Construct a coordinate system name from an hcs, orientation and vcs.

name_list(what[, datum_filter])

Get a list of coordinate system names

parameter_exists(what, key)

Test if a parameter set exists in a coordinate system table.

parameters(what, key)

Get a dictionary of parameters for a coordinate system item.

wkt_vcs(vcs)

Compose a wkt VERTCS block from a Geosoft vcs string.

Classes

Coordinate_system([coordinate_system])

Coordinate system class.

Coordinate_translate(cs_from, cs_to)

Class to reproject coordinates between different coordinate systems.

Wkt(wkt)

Helper class to parse WKT-formatted spatial reference strings.

Exceptions

CSException(message)

Exceptions from geosoft.gxpy.coordinate_system.