2.3.3.3.112. NXem_conventions_ebsd

Status:

base class, extends NXem_conventions

Description:

Base class for method-specific conventions EBSD. ...

Base class for method-specific conventions EBSD.

This base class is expected to be used with NXem_conventions.

This is the main issue which currently is not in all cases documented and thus limits the interoperability and value of collected EBSD data. Not communicating EBSD data with such contextual pieces of information and the use of file formats which do not store this information is the key unsolved problem.

Symbols:

No symbol table

Groups cited:

NXcoordinate_system, NXprocess

Structure:

gnomonic_projection_reference_frame: (optional) NXcoordinate_system

Details about the gnomonic projection reference frame.

type: (optional) NX_CHAR ⤆

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

Type of coordinate system/reference frame used for identifying positions in the gnomonic projection space Xg, Yg, Zg according to DOI: 10.1016/j.matchar.2016.04.008.

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 ⤆

Is the origin of the gnomonic coordinate system located ...

Is the origin of the gnomonic coordinate system located where we assume the location of the pattern centre. This is the location Xg = 0, Yg = 0, Zg = 0 according to reference DOI: 10.1016/j.matchar.2016.04.008.

Any of these values: undefined | in_the_pattern_centre

x_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing "gnomomic" x-axis base ...

Direction of the positively pointing “gnomomic” x-axis base vector when viewing how the diffraction pattern looks on the detector screen. 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_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing "gnomomic" y-axis base ...

Direction of the positively pointing “gnomomic” y-axis base vector when viewing how the diffraction pattern looks on the detector screen. 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_direction: (optional) NX_CHAR ⤆

Direction of the positively pointing "gnomomic" z-axis base ...

Direction of the positively pointing “gnomomic” z-axis base vector when viewing how the diffraction pattern looks on the detector screen. 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

pattern_centre: (optional) NXprocess

Details about the definition of the pattern centre ...

Details about the definition of the pattern centre as a special point in the gnomonic projection reference frame.

x_boundary_convention: (optional) NX_CHAR

From which border of the EBSP (in the detector reference frame) ...

From which border of the EBSP (in the detector reference frame) is the pattern centre’s x-position (PCx) measured? Keywords assume the region-of-interest is defined by a rectangle. We observe this rectangle and inspect the direction of the outer-unit normals to the edges of this rectangle.

Any of these values: undefined | top | right | bottom | left

x_normalization_direction: (optional) NX_CHAR

In which direction are positive values for PCx measured from ...

In which direction are positive values for PCx measured from the specified boundary. Keep in mind that the gnomonic space is in virtually all cases embedded in the detector space. Specifically, the XgYg plane is defined such that it is embedded/laying inside the XdYd plane (of the detector reference frame). When the normalization direction is the same as e.g. the detector x-axis direction, we state that we effectively normalize in fractions of the width of the detector.

The issue with terms like width and height is that these degenerate if the detector region-of-interest is square-shaped. This is why we should better avoid talking about width and height but state how we would measure distances practically with a ruler and how we then measure positive distances.

Any of these values: undefined | north | east | south | west

y_boundary_convention: (optional) NX_CHAR

From which border of the EBSP (in the detector reference ...

From which border of the EBSP (in the detector reference frame) is the pattern centre’s y-position (PCy) measured? For further details inspect the help button of xaxis_boundary_convention.

Any of these values: undefined | top | right | bottom | left

y_normalization_direction: (optional) NX_CHAR

In which direction are positive values for PCy measured from ...

In which direction are positive values for PCy measured from the specified boundary. For further details inspect the help button of xaxis_normalization_direction.

Any of these values: undefined | north | east | south | west

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_ebsd.nxdl.xml