Filling Out List Index-based Classes

The Geometry dictionary classes include a number of complex documentation cases that require defining and referencing lists of values. Individual elements of the list are accessed by index. The type of value listed can vary and may or may not have associated units. The classes defined on this page are abstract classes - you will not see them by the names they have here in labels, but rather will see a more high-level class name with the content listed below. So, for example, when describing lander geometry you may encounter the <Device_Angle_Index> class, which will have the same content as the <List_Angle_Index> class described below (but of course different enclosing tags).

List_Index_Angle

Classes based on this abstract class have list values that are angles.

<index_sequence_number> or <index_name> or <index_id>

OPTIONAL

You may include zero, one, two, or all three of these attributes, but you may not repeat any of them.

There appears to be no difference between these three things. They have equally vague definitions and identical data types.

<Local_Internal_Reference>

OPTIONAL

It is not clear why this is here or what it could possibly be referencing.

<index_value_angle>

OPTIONAL

This attribute is defined as being "the value of an angle as named by the associated index_id or index_name". You must specify an angular unit of measure with this value. You may repeat this attribute as appropriate.

The definition makes no sense. The attribute is optional to begin with, as are both the referenced identification attributes (and the third option for identification is omitted). Index values should be unitless integers, not real numbers with units. And the definition implies that this must be single-valued (what would it even mean to have multiple, non-integral index values for a "list"?!?), but this attribute is repeatable.

List_Index_Length

Classes based on this abstract class have values that are lengths.

<index_sequence_number> or <index_name> or <index_id>

OPTIONAL

You may include zero, one, two, or all three of these attributes, but you may not repeat any of them.

There appears to be no difference between these three things. They have equally vague definitions and identical data types.

<Local_Internal_Reference>

OPTIONAL

It is not clear why this is here or what it could possibly be referencing.

<index_value_length>

OPTIONAL

This attribute is defined as being "the value of a length as named by the associated index_id or index_name". You must specify a unit of lengthwith this value. You may repeat this attribute as appropriate.

This attribute has all the problems mentioned in the previous class for index_value_angle.

List_Index_No_Units

Classes based on this abstract class have unitless values.

<index_sequence_number> or <index_name> or <index_id>

OPTIONAL

You may include zero, one, two, or all three of these attributes, but you may not repeat any of them.

There appears to be no difference between these three things. They have equally vague definitions and identical data types.

<Local_Internal_Reference>

OPTIONAL

It is not clear why this is here or what it could possibly be referencing.

<index_value_number>

OPTIONAL

This attribute is defined as being "the value with no applicable units as named by the associated index_id or index_name". You may repeat this attribute as appropriate.

This attribute has all the problems mentioned in the previous class for index_value_angle.

List_Index_Temperature

Classes based on this abstract class have values that are temperatures.

<index_sequence_number> or <index_name> or <index_id>

OPTIONAL

You may include zero, one, two, or all three of these attributes, but you may not repeat any of them.

There appears to be no difference between these three things. They have equally vague definitions and identical data types.

<Local_Internal_Reference>

OPTIONAL

It is not clear why this is here or what it could possibly be referencing.

<index_value_temperature>

OPTIONAL

This attribute is defined as being "the value of a temperature as named by the associated index_id or index_name". You must specify a unit of temperature with this value. You may repeat this attribute as appropriate.

This attribute has all the problems mentioned in the previous class for index_value_angle.

List_Index_Text

Classes based on this abstract class have values that are strings.

<index_sequence_number> or <index_name> or <index_id>

OPTIONAL

You may include zero, one, two, or all three of these attributes, but you may not repeat any of them.

There appears to be no difference between these three things. They have equally vague definitions and identical data types.

<Local_Internal_Reference>

OPTIONAL

It is not clear why this is here or what it could possibly be referencing.

<index_value_string>

OPTIONAL

This attribute is defined as being "the string value as named by the associated index_id or index_name". You may repeat this attribute as appropriate.

This attribute has all the problems mentioned in the previous class for index_value_angle.