2.3.3.3.111. NXem_conventions

Status:

base class, extends NXobject

Description:

Conventions for rotations and coordinate systems to interpret crystal orientatio ...

Conventions for rotations and coordinate systems to interpret crystal orientation and other data and results collected with electron microscopy research.

Documenting explicitly all used conventions and coordinate systems is the decisive context whereby many results from electron microscopy are at all interpretable.

Symbols:

No symbol table

Groups cited:

NXcoordinate_system, NXem_conventions_ebsd, NXobject

Structure:

rotation_conventions: (optional) NXobject

Mathematical conventions and materials-science-specific conventions ...

Mathematical conventions and materials-science-specific conventions required for interpreting every collection of orientation data.

rotation_handedness: (optional) NX_CHAR

Convention how a positive rotation angle is defined when viewing ...

Convention how a positive rotation angle is defined when viewing from the end of the rotation unit vector towards its origin, i.e. in accordance with convention 2 of DOI: 10.1088/0965-0393/23/8/083501. Counter_clockwise is equivalent to a right-handed choice. Clockwise is equivalent to a left-handed choice.

Any of these values: undefined | counter_clockwise | clockwise

rotation_convention: (optional) NX_CHAR

How are rotations interpreted into an orientation ...

How are rotations interpreted into an orientation according to convention 3 of DOI: 10.1088/0965-0393/23/8/083501.

Any of these values: undefined | passive | active

euler_angle_convention: (optional) NX_CHAR

How are Euler angles interpreted given that there are several ...

How are Euler angles interpreted given that there are several choices (e.g. ZXZ, XYZ, etc.) according to convention 4 of DOI: 10.1088/0965-0393/23/8/083501. The most frequently used convention is ZXZ which is based on the work of H.-J. Bunge but other conventions are possible.

Any of these values: undefined | zxz

axis_angle_convention: (optional) NX_CHAR

To which angular range is the rotation angle argument of an ...

To which angular range is the rotation angle argument of an axis-angle pair parameterization constrained according to convention 5 of DOI: 10.1088/0965-0393/23/8/083501.

Any of these values: undefined | rotation_angle_on_interval_zero_to_pi

sign_convention: (optional) NX_CHAR

Which sign convention is followed when converting orientations ...

Which sign convention is followed when converting orientations between different parameterizations/representations according to convention 6 of DOI: 10.1088/0965-0393/23/8/083501.

Any of these values: undefined | p_plus_one | p_minus_one

processing_reference_frame: (optional) NXcoordinate_system

Details about eventually relevant named directions that may ...

Details about eventually relevant named directions that may give reasons for anisotropies. The classical example is cold-rolling where one has to specify which directions (rolling, transverse, and normal) align how with the direction of the base vectors of the sample_reference_frame.

type: (optional) NX_CHAR ⤆

Type of coordinate system and reference frame according to ...

Type of coordinate system and reference frame according to convention 1 of DOI: 10.1088/0965-0393/23/8/083501.

Any of these values: undefined | cartesian

handedness: (optional) NX_CHAR ⤆

Handedness of coordinate system. ...

Handedness of coordinate system.

Any of these values: right_handed | left_handed

origin: (optional) NX_CHAR ⤆

Location of the origin of the processing_reference_frame. ...

Location of the origin of the processing_reference_frame. This specifies the location Xp = 0, Yp = 0, Zp = 0. Assume regions-of-interest in this reference frame form a rectangle or cuboid. Edges are interpreted by inspecting the direction of their outer unit normals (which point either parallel or antiparallel) along respective base vector direction of the reference frame.

Any of these values:

  • undefined

  • front_top_left

  • front_top_right

  • front_bottom_right

  • front_bottom_left

  • back_top_left

  • back_top_right

  • back_bottom_right

  • back_bottom_left

x_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the x-axis base vector, ...

Name or alias assigned to the x-axis base vector, e.g. rolling direction.

x_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing x-axis base vector of ...

Direction of the positively pointing x-axis base vector of the processing_reference_frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

y_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the y-axis base vector, ...

Name or alias assigned to the y-axis base vector, e.g. transverse direction.

y_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing y-axis base vector of ...

Direction of the positively pointing y-axis base vector of the processing_reference_frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. For further information consult also the help info for the xaxis_direction field.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

z_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the z-axis base vector, ...

Name or alias assigned to the z-axis base vector, e.g. normal direction.

z_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing z-axis base vector of ...

Direction of the positively pointing z-axis base vector of the processing_reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. For further information consult also the help info for the xaxis_direction field.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

sample_reference_frame: (optional) NXcoordinate_system

Details about the sample/specimen reference frame.

type: (optional) NX_CHAR ⤆

Type of coordinate system and reference frame according to ...

Type of coordinate system and reference frame according to convention 1 of DOI: 10.1088/0965-0393/23/8/083501. The reference frame for the sample surface reference is used for identifying positions on a (virtual) image which is formed by information collected from an electron beam scanning the sample surface. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. Reference DOI: 10.1016/j.matchar.2016.04.008 The sample surface reference frame has coordinates Xs, Ys, Zs. In three dimensions these coordinates are not necessarily located on the surface of the sample as there are multiple faces/sides of the sample. Most frequently though the coordinate system here is used to define the surface which the electron beam scans.

Any of these values: undefined | cartesian

handedness: (optional) NX_CHAR ⤆

Handedness of the coordinate system if it is a Cartesian. ...

Handedness of the coordinate system if it is a Cartesian.

Any of these values: right_handed | left_handed

origin: (optional) NX_CHAR ⤆

Location of the origin of the sample surface reference frame. ...

Location of the origin of the sample surface reference frame. This specifies the location Xs = 0, Ys = 0, Zs = 0. Assume regions-of-interest in this reference frame form a rectangle or cuboid. Edges are interpreted by inspecting the direction of their outer unit normals (which point either parallel or antiparallel) along respective base vector direction of the reference frame.

Any of these values:

  • undefined

  • front_top_left

  • front_top_right

  • front_bottom_right

  • front_bottom_left

  • back_top_left

  • back_top_right

  • back_bottom_right

  • back_bottom_left

x_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the x-axis base vector, ...

Name or alias assigned to the x-axis base vector, e.g. longest edge.

x_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing x-axis base vector of ...

Direction of the positively pointing x-axis base vector of the sample surface reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. Different tools assume that different strategies can be used and are perceived as differently convenient to enter details about coordinate system definitions. In this ELN users have to possibility to fill in what they assume is sufficient to define the coordinate system directions unambiguously. Software which works with this user input needs to offer parsing capabilities which detect conflicting input and warn accordingly.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

y_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the y-axis base vector, ...

Name or alias assigned to the y-axis base vector, e.g. long edge.

y_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing y-axis base vector of ...

Direction of the positively pointing y-axis base vector of the sample surface reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. For further information consult also the help info for the xaxis_direction field.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

z_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the z-axis base vector, ...

Name or alias assigned to the z-axis base vector, e.g. shortest edge.

z_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing z-axis base vector of ...

Direction of the positively pointing z-axis base vector of the sample surface reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. For further information consult also the help info for the xaxis_direction field.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

detector_reference_frameID: (optional) NXcoordinate_system

Details about the detector reference frame for a specific detector.

@detector: (optional) NX_CHAR

Reference to the specifically named :ref:`NXdetector` instance ...

Reference to the specifically named NXdetector instance for which these conventions in this NXprocess group apply (e.g. /entry1/instrument/detector1).

type: (optional) NX_CHAR ⤆

Type of coordinate system/reference frame used for ...

Type of coordinate system/reference frame used for identifying positions in detector space Xd, Yd, Zd, according to DOI: 10.1016/j.matchar.2016.04.008.

Any of these values: undefined | cartesian

handedness: (optional) NX_CHAR ⤆

Handedness of the coordinate system if it is a Cartesian. ...

Handedness of the coordinate system if it is a Cartesian.

Any of these values: right_handed | left_handed

origin: (optional) NX_CHAR ⤆

Where is the origin of the detector space reference ...

Where is the origin of the detector space reference frame located. This is the location of Xd = 0, Yd = 0, Zd = 0. Assume regions-of-interest in this reference frame form a rectangle or cuboid. Edges are interpreted by inspecting the direction of their outer unit normals (which point either parallel or antiparallel) along respective base vector direction of the reference frame.

Any of these values:

  • undefined

  • front_top_left

  • front_top_right

  • front_bottom_right

  • front_bottom_left

  • back_top_left

  • back_top_right

  • back_bottom_right

  • back_bottom_left

x_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the x-axis base vector, ...

Name or alias assigned to the x-axis base vector, e.g. longest edge as some landmark on the detector.

x_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing x-axis base vector of ...

Direction of the positively pointing x-axis base vector of the detector space reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. Different tools assume that different strategies can be used and are perceived as differently convenient to enter details about coordinate system definitions. In this ELN users have to possibility to fill in what they assume is sufficient to define the coordinate system directions unambiguously. Software which works with this user input needs to offer parsing capabilities which detect conflicting input and warn accordingly.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

y_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the x-axis base vector, ...

Name or alias assigned to the x-axis base vector, e.g. long edge as some landmark on the detector.

y_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing y-axis base vector of ...

Direction of the positively pointing y-axis base vector of the detector space reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. For further information consult also the help info for the xaxis_direction field.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

z_alias: (optional) NX_CHAR ⤆

Name or alias assigned to the x-axis base vector, ...

Name or alias assigned to the x-axis base vector, e.g. short edge as some landmark on the detector.

z_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing z-axis base vector of ...

Direction of the positively pointing z-axis base vector of the detector space reference frame. We assume the configuration is inspected by looking towards the sample surface from a position that is located behind the detector. For further information consult also the help info for the xaxis_direction field.

Any of these values:

  • undefined

  • north

  • east

  • south

  • west

  • in

  • out

EM_CONVENTIONS_EBSD: (optional) NXem_conventions_ebsd

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXem_conventions.nxdl.xml