Environmental Data Coding Specification
Table 10.1 -- Table of contents
This International Standard specifies the rules and guidelines that shall be followed in preparing registration
proposals. Registration proposals include required information for new concepts in each EDCS dictionary, as well as
accompanying administrative information (see Annex J Templates for registration proposals).
The guidelines in 10.2 Guidelines for definitions for
registered items through 10.5 Guidelines for
references for registered items shall apply to all registered items. The additional guidelines in 10.6
Guidelines for registration of ECs through 10.14
Guidelines for registration of EDCS profiles shall apply only to the indicated categories of registered items.
The definitions in this International Standard were created by applying a set of guidelines. Definitions for proposed
registered EDCS dictionary entries shall be created according to the following guidelines:
- A definition shall be provided for each EDCS dictionary entry. This definition shall contain at least one
word, number, expression, or formula.
- Definitions shall be clear and concise, containing only the content necessary to specify the concept.
- Complete sentences shall be used except when a single word or phrase is unambiguous.
- A single sentence shall be used except when multiple sentences are necessary to add significantly to the clarity
and completeness of the definition.
- Words or short phrases that are not used in the definition and that compactly denote the concept and may be useful
in EDCS label formation may be included at the end of the definition. If such words or short phrases are included,
they shall be separated from the remainder of the definition by a semicolon. If the definition of a concept does not
contain the exact or approximate key words that were used to form the EDCS label for the concept, then those words
shall be included at the end of the definition. For example: The definition of EC
HAIL might be "Frozen precipitation falling in a shower or storm of pellets; hail."
- In some cases, a concept may used in the definition of another concept. If an EC
is used in the definition of another concept, this use shall be represented in the definition by placing the EDCS
label for that EC in single angle brackets (< >) in the definition. Because
ECs are used in definitions in a manner similar to nouns, only noun usage is
represented by single angle brackets. For example, the EC RAIN is used as a noun
in the definition: "<RAIN> at time of observation." while the word "rain" is used as an
adjective in the definition: "Rain shower(s) at time of observation." If an EA
is used in the definition of another concept, this use shall be represented in the definition by placing the EDCS
label for that EA in double angle brackets (<< >>) in the definition. For
example: The definition of EA TERRAIN_HEIGHT might be: "The <<HEIGHT>> of the
<TERRAIN>."
- If an EE concept is used in the definition of another EE
concept of the same EA, this use shall be represented in the definition by placing the
label for that EE in triple angle brackets (<<< >>>) in
the definition.
- The definition of an EE for a given EA shall
not reference an EE which is an EE
of a different EA.
- If a definition includes a list of exemplars of the concept, that list shall be placed at the end of the
definition in a separate sentence that begins "Examples: ". For example: An EE
INERT_MATERIAL might have the definition "Inert <MATERIAL>s. Examples: sand, dirt, gravel, and
snow."
- Definitions shall be unambiguous and worded to clearly express a single concept.
- Where a set is being defined, the EC SET shall be used. For example: "A
<SET> of indicator lights."
- Jargon shall not be used.
- Abbreviations shall not be used.
- Acronyms shall be used only if they are defined in Table
3.3 Abbreviated terms.
- If an acronym is defined in Table 3.3 Abbreviated terms,
it shall be used wherever the phrase would have appeared. That is, the phrase shall not be used except in Table
3.3 Abbreviated terms; wherever the phrase might have appeared, the acronym shall be used instead.
- No units of measure shall be abbreviated.
- Unit symbols shall not be used except in the definitions of concepts in the EU
Dictionary. For example: use "metres per second" instead of "m/s".
- References shall not be embedded in definitions with one exception. Where a reference is used not as the source of
a definition, but rather to define the format and/or values of an EA whose EDCS
attribute value type is CONSTRAINED_STRING, STRING, or KEY, that reference may be part of the definition.
- Definitions shall be atomic, self-contained and independent of all other entries in the same EDCS dictionary with
the exception that an EE definition is dependent on the definition of its
corresponding EA. The context of the corresponding EA
shall be used to interpret an EE definition.
- Definitions shall be unique within the same EDCS dictionary.
- Units of measure should not be used in the definition fields of EC dictionary
entries.
- Units of measure shall not be used in the definition fields of ES, EQ,
EO, or EG dictionary entries.
- Terms appearing in units of measure may be used in definitions where appropriate. For example: "Tesla
coil" and "metre stick".
- The word "that" shall be used only to introduce restrictive clauses, that is, clauses that are an
essential part of a definition where if the clause is eliminated, the meaning of the definition changes. Restrictive
clauses shall not be separated from the remainder of the definition by a comma.
- The word "which" shall be used only to introduce non-restrictive clauses, that is, clauses that are not
an essential part of a definition where if the clause is eliminated, the meaning of the definition does not change.
Non-restrictive clauses shall be separated from the remainder of the definition by a comma.
- If the reference type for an EDCS dictionary entry is AR or PR,
the definition shall be derived from the definition of the cited concept in the referenced document. In cases where
the full definition is too complex to repeat the definition in its entirety in this International Standard, the
concept definition may be of the form "See [R].". "R" shall be a well-formed citation (see
4.3.4.4 Citation format) of a concept in an external document.
This document shall be listed in either 2 Normative references, specified in this
registration proposal, or specified in another registered item.
- If the reference type is DR then a citation shall be provided
to a dictionary. In this case the following guidelines relate the definition and the citation:
- The dictionary cited may be a specialized technical dictionary. This specialized technical dictionary shall be
listed in either Bibliography, specified in this registration proposal, or
specified in another registered item.
- The dictionary cited may be the New Shorter Oxford English Dictionary [NSOED].
This is done in this International Standard for emphasis only, since this is the default manner that the meaning
of any text in an International Standard is determined. This convention allows this International Standard to
require that each EDCS dictionary entry have at least one reference and avoids any confusion over how a
definition is to be interpreted.
The labels in this International Standard were created by applying a set of guidelines. Labels for proposed
registered EDCS dictionary entries shall be created according to the following guidelines:
- A label shall be provided for each EDCS dictionary entry.
- Labels shall be character strings.
- Labels shall begin with an alphabetic character (and therefore labels shall contain at least one character).
- Labels shall contain only uppercase characters (A-Z) with two exceptions:
- relational operators ("gt", "lt", "ge", "le", "eq", and
"ne"); and
- the radix delimiter symbol "r".
- Labels shall not contain spaces.
- Labels may be a single word or may be composed of a series of components each of which is a word, an
abbreviation, or an acronym/initialism.
- The underscore "_" character shall be used to concatenate the components of a label.
- Labels should be as short as possible while capturing a common use descriptive word or phrase representative of
the concept.
- The length of a label shall not exceed fifty-nine (59) characters.
- To facilitate the direct use of labels in programming language bindings where there are restrictions on the length
and uniqueness of symbolic constants, the label, or the initial portion of the label, shall be unique within the set
of all EDCS dictionaries in the following manner:
- EELs shall be unique within the set of EELs
of the same EA. For example: the same label could also be used for an EEL
of a different EA.
- EGLs shall be unique within the set of EGLs of
the same EO.
- All other labels shall be unique within the set of labels of concepts in their EDCS dictionary.
- Within the set of EELs of the same EA,
EELs shall be unique in the first nineteen (19) characters.
- Within the set of EGLs of the same EO,
EGLs shall be unique in the first nineteen (19) characters.
- All other labels shall be unique in the first twenty-seven (27) characters.
The components of a label shall be chosen according to the following guidelines:
- The order of the components in a label shall be in the natural order in which the components are likely to be used
within an English phrase.
- Components of labels shall not be used with a different meaning from how that component is used elsewhere in this
International Standard or in previously registered EDCS dictionary entries.
- Verbs, articles, conjunctions, negations, and prepositions shall not be used as components of a label except where
required for clarity.
- Abbreviations of words and phrases should only be used where necessary to meet the uniqueness criteria of labels.
- When abbreviating, if a word or phrase to be abbreviated appears in Annex H. Abbreviations
and acronyms used in the construction of labels, the given abbreviation for that word or phrase shall be used.
- When abbreviating, if a word or phrase to be abbreviated does not appear in Annex H.
Abbreviations and acronyms used in the construction of labels; the proposed abbreviation should be consistent in
style with those specified in Annex H. Abbreviations and acronyms used in the construction of
labels, if possible.
Recognized abbreviations for words and acronyms for phrases may be used as components of a label based on the
following guidelines:
- Each abbreviation shall uniquely represent a single word.
- A single abbreviation shall not represent a combination of words.
- Each acronym shall uniquely represent a single multi-word phrase.
- If a word is abbreviated in one label, it is not required to be abbreviated in other labels.
- If a word is abbreviated in one label, the same abbreviation should be used wherever that word is abbreviated.
- If a phrase is replaced by an acronym in one label, it is not required to be replaced in other labels.
- If a phrase is replaced by an acronym in one label, the same acronym should be used wherever that phrase is
intended.
- For each EA of EDCS attribute value type ENUMERATION, abbreviations shall be used
consistently across all labels within its set of EEs (i.e., either a word or
phrase is always abbreviated, or never abbreviated).
- New acronyms may be defined if necessary to create a label whose length meets the criteria defined in (i) and (j).
- Jargon shall not be used.
- An acronym or abbreviation in a label shall not be, by itself, a word with a different meaning than that of the
word and/or phrase that it replaces. For example: the acronym LOST should not be used for the phrase
"Line of Sight Type".
Units of measure or abbreviations for units of measure shall not be used as components of labels with three
exceptions:
- Labels of EUs,
- Labels of EEs, and
- Labels in which the unit of measure or its abbreviation is not used as a unit of measure such as "TESLA_COIL"
or "METRE_STICK".
Codes not assigned in this International Standard are reserved for future standardization or for registration.
Assigned codes include the deprecated codes of Annex B. Codes shall be assigned by the ISO
International Registration Authority for Graphical Items according to these rules:
- Nothing should be assumed about the relationship among EDCS dictionary entries from the numerical relationships of
their corresponding codes. For example, the numerical sequencing of codes does not impose any sequential ordering to
the concepts denoted by those codes.
- Signed integers are used to represent codes even though only positive integer values shall ever be assigned in
either this International Standard or through registration. This allows negative integer values to be used
experimentally in applications, even though such use of negative integer values is not in conformance to this
International Standard.
- The ISO International Registration Authority for Graphical Items shall assign codes in increasing order beginning
at the first available integer value, and skipping no integer values, within the set of codes for each EDCS
dictionary.
- The ISO International Registration Authority for Graphical Items shall coordinate the assignment of codes with
future revisions of this International Standard to ensure that no code shall be assigned more than once by either
standardization or registration.
The references in this International Standard were created by applying a set of guidelines.
References for proposed registered EDCS dictionary entries shall be created according to the following guidelines:
-
A reference type shall be provided for each EDCS dictionary entry (see 4.3.4.2
Reference types).
-
The reference type shall be selected in accordance with the following guidelines:
-
If the proposed registered concept is intended to represent the same concept defined in
another specification suitable for referencing from an International Standard, the reference type shall be
either AR or PR. The current
edition [ISOD2] may be consulted to determine if a specification is suitable
for normative referencing from an International Standard. If a specification is not suitable normative
referencing then the reference type shall be IR or DR.
-
If the proposed registered concept was adapted from another document, but the adapted
concept definition is sufficiently different from the definition in the other document that a reference type of AR
or PR is not appropriate, the reference type shall be IR
or DR.
-
If the words in the definition of the proposed registered concept are derived from, or
interpreted in accordance with, dictionary definitions, the reference type shall be DR
and the additional guidelines specified in 10.2 Guidelines for definitions of registered items (aa)
shall also be followed.
-
Citations shall be formulated in conformance to the specifications in 4.3.4.4
Citation format while considering the following additional guidelines:
-
The citations shall be appropriate for the reference type and the definition of the
proposed registered concept.
-
Where possible, references should be chosen from either 2
Normative references or the Bibliography.
-
If no reference in either 2 Normative references or the Bibliography
is suitable then a new reference may be specified in the proposed registered concept. The specification of
the reference shall include both a short identifier for the reference and a full bibliographic citation
formatted in conformance to the rules in [I690].
-
If more than one citation is provided, the reference type shall be IR
(see 4.3.4.2 Reference types, (d) Informative reference).
No additional guidelines shall apply to the registration of concepts in the EC
Dictionary.
Concepts in the EA Dictionary shall be registered according to the following
additional guidelines:
- If the EDCS attribute value type is ENUMERATION, at least one new EE
corresponding to that EA shall also be registered. If a set of EEs
corresponding to the same EA are registered at the same time, the EEs
shall be listed in a natural order.
- If the EDCS attribute value type is REAL and the EQ appropriate for the
specification of the values of the EA is not previously defined in this International
Standard or by registration, at least one new EQ and, if necessary, one
new EU that is a member of that EQ shall also be
registered.
- The EDCS attribute value type of COUNT shall be used if and only if the concept is a
count of a whole number of some entity. For example: the number of entities observed per hour.
- The EDCS attribute value type of INTEGER shall be used for concepts that are integer valued but are not a count of
a whole number of some entity.
No additional guidelines shall apply to the registration of concepts in the EV
Dictionary.
Concepts in the EE Dictionary shall be registered according to the following
additional guidelines:
- Definitions of EEs shall not repeat any portion of the definition of the
corresponding EA, unless such repetitions significantly enhance the readability of the
definition. For example: an EA whose definition is "The function of a
building." shall not have an EE whose definition is "An
administrative building."
- EEs of different EAs may have identical
definitions or labels.
- No deprecated unit of measure (identified in Annex B) shall be used, with the
following two exceptions:
- When a unit appearing in Annex B is needed to ensure clarity for a community of EDCS users, it shall appear in
parentheses following a unit of measure that is consistent with an entry in the EDCS Unit Dictionary. For
example: "12,2 metres (40 feet)".
- The use of the term "approximately" associated with a value and a deprecated unit of measure for
that value within parentheses is acceptable, but not necessary. For example: "12,2 metres (approximately 40
feet)".
- Units of measure may be used in EAs, where they are used to specify the conditions
under which an attribute value pertains, but this use should be avoided where possible.
- When an EA of EDCS attribute value type ENUMERATION is intended to be used to
specify the format of instances of other EAs of EDCS attribute value type
CONSTRAINED_STRING, then one EE of this EA
shall have the label "UNCONSTRAINED" and shall be defined as: "A Basic Latin string whose contents
are not further constrained."
Concepts in the EU Dictionary shall be registered according to the following additional
guidelines:
- Entries in the symbol, quantity, and definition fields should be derived in accordance with the requirements in [I31],
including how quantities, multiplication, division, and logarithms are specified.
- Concepts incorporating the symbols for EDCS unit scales in their definitions are acceptable; however:
- If a "pure" equivalent non-scaled unit of measure concept is not already an EU
concept, it shall be registered. The EQL for the newly
registered non-scaled unit of measure concept shall be used as the EQL
for the newly registered scaled unit of measure concept.
- The EU concept should be defined in terms of the "pure" non-scaled unit of
measure concept by including an equation of the general form "<scale definition><non-scaled unit
symbol>".
- The EU's symbol should include the symbols for the scaled unit(s), as appropriate.
- If no standardized or registered EQ concept is appropriate for the EU
concept being registered, a new EQ concept shall also be registered.
No additional guidelines shall apply to the registration of concepts in the EQ
Dictionary.
No additional guidelines shall apply to the registration of concepts in the EO
Dictionary.
Concepts in the EG Dictionary shall be registered according to one additional guideline. EG
concepts that are members of different EOs may have identical definitions
or labels.
EDCS profiles shall be registered according to the following additional guidelines:
- An EDCS profile shall specify a subset of this International Standard and its registered concepts as:
- a list of EDCS dictionaries,
- for each listed EDCS dictionary, a list of entries in that dictionary, and
- optionally, EDCS profile constraints that restrict either EDCS
dictionary entries or the relationships among EDCS dictionary entries or both.
- EDCS profile constraints may additionally restrict:
- the EDCS representation types (see 9.2 EDCS
representation types) for implementing abstract elements of this International Standard,
- the values or range of values of an EA, and
- in the case of an EA of EDCS attribute value type REAL, the EUs
and ESs that may be used with that EA.
- An EDCS profile constraint may restrict the EDCS representation type used for implementing EDCS attribute value
types as follows:
- If the EDCS attribute value type is STRING, CONSTRAINED_STRING, or KEY, an EDCS profile constraint may
restrict:
- string length either to a fixed number of characters or to a length between a specified minimum and a
specified maximum length, and
- string value to only contain characters from a restricted subset of the characters specified in [I10646].
- If the EDCS attribute value type is REAL, INTEGER, COUNT, INDEX, ENUMERATION, BOOLEAN, or NULL, the EDCS
representation type cannot be constrained.
- An EDCS profile constraint may restrict the values, or the ranges of values of EAs
as follows:
- If the EDCS attribute value type is REAL, INTEGER, COUNT, or INDEX, an EDCS profile constraint may restrict
the allowed values to a specified subset of the allowed values or to a range of allowed values.
- If the EDCS attribute value type is STRING, CONSTRAINED_STRING, or KEY, an EDCS profile constraint may
restrict string values to a specified subset of the allowed values.
- If the EDCS attribute value type is ENUMERATION, an EDCS profile constraint may restrict the allowed values to
a specified subset of the EEs for that EA.
- If the EDCS attribute value type is BOOLEAN, an EDCS profile constraint may exclude one of the possible
values.
- If the EDCS attribute value type is NULL, the values cannot be constrained.
- An EDCS profile constraint may restrict the EUs and ESs
that may be used with an EA as follows:
- Restrict the allowed EUs to a specified subset of the EUs
that are members of the EQ associated with the EA.
- Restrict the allowed ESs to a specified subset of the ESs
specified in Table 7.9 -- Unit Scale
Dictionary for powers of 10 and Table
7.10 -- Unit Scale Dictionary for powers of 210.
1) At the time this International Standard was published, the ISO
International Registration Authority for Graphical Items was the United States National Imagery and Mapping Agency (NIMA).
The mailing address was: Registration Authority, National Imagery and Mapping Agency, c/o Joint Interoperability Test
Command, Building 57305, Room 263A, Fort Huachuca, Arizona 85613-7020. USA.
http://www.iso.ch/iso/en/ittf/PubliclyAvailableStandards/ISO_IEC_18025_Ed1.html