Table 6.233—DRM_Regular_Axis

Property

Description

Superclass

·         <DRM Axis>

Class

·         <DRM Regular Axis>

Subclass

·         none

Definition

An object of this DRM class specifies a <DRM Axis> that uses a constant spacing between hash marks and numerical values.

Example(s)

·         Digital Terrain Elevation Data (DTED) is sampled in a regular grid of latitude and longitude points. Accordingly, the latitude and longitude <DRM Axis>s resulting <DRM Data Table> are <DRM Regular Axis>s.

·         A table of wind-chill values has axes of air temperature and wind speed. Air temperature typically starts at 0 degree Celsius and is decremented in intervals of 1 degree. Wind speed starts at calm (0 mph) and is incremented at intervals of 5 mph. Consequently, the air temperature and wind-speed axes of this table are <DRM Regular Axis>s.

Inherited field elements

field_name

range

Field_Data_Type

axis_type1

 

Element_Type

value_unit2

 

EDCS_Unit_Code

value_scale3

 

EDCS_Scale_Code

axis_value_count4

 

Short_Integer_Positive

Field elements

field_name

range

Field_Data_Type

interpolation_type5

 

Interpolation_Type

first_value6

 

Property_Data_Value

spacing7

 

Property_Data_Value

spacing_type8

 

Spacing_Type

axis_alignment9

 

Axis_Alignment

Associated to (one-way) (inherited)

·         none

Associated to (one-way)

·         none

Associated by (one-way) (inherited)

·         none

Associated by (one-way)

·         none

Associated with (two-way) (inherited)

·         none

Associated with (two-way)

·         none

Composed of (two-way) (inherited)

·         none

Composed of (two-way)

·         none

Composed of (two-way metadata) (inherited)

·         none

Composed of (two-way metadata)

·         none

Component of (two-way) (inherited)

·         zero or more <DRM Property Grid>s

·         zero or more <DRM Property Table>s

Component of (two-way)

·         zero or more <DRM Mesh Face Table>s

Constraints

·         Axis type restrictions

·         Relative spatial axes values

Notes

1 Specifies the property being described by the <DRM Axis>.

2 Specifies the unit of measurement of the <DRM Axis>, which shall be compatible with the requirements imposed by axis_type. If axis_type does not require a unit of measurement, for example, if axis_type requires a value_type of STRING, then value_unit shall be set to EUC_UNITLESS.

3 Specifies the scale applicable to value_unit. If axis_type does not require a unit of measurement, for example, if axis_type requires a value_type of STRING, then value_scale shall be set to ESC_UNI.

4 Indicates the number of "hash marks" along the axis.

5 Allows the data supplier to indicate how best to interpolate the data to points that are in-between grid points on the axis. Interpolation type INTERPRETATION_DISALLOWED is required for axis type ENUMERATED_AXIS. When a <DRM Data Table> has more than one axis, the order of the interpolations is in the order of axis definitions.

6 First_value is the first numeric value on the axis.

7 Spacing is the distance between hash marks; the arithmetic difference for linear axes and  the logarithmic difference for logarithmic axes. I.e., counting from 0, the value for tick 'N' is = first_value + N * spacing (for linear), and is = first_value * spacing^N (for logarithmic).

8 Indicates how the spacing value is used to compute tick marks.

9 Axis_alignment indicates the position of the axis with respect to the axis interval. Note that LOWER and UPPER refer to the axis INDEX (e.g., LOWER means aligned to the side with the lower index).

Class diagram

<DRM Regular Axis>