This document describes how environmental concepts are mapped from the EDCS Version 4.1 to FACC Edition 2.1.

Table of Contents

Part 1: EDCS Version 4.1 Background

1. Overview
2. Denoting a Concept

Part 2: FACC Edition 2.1 Background

1. Overview
2. Denoting a Concept

Part 3: Concept Mapping from EDCS Version 4.1 to FACC Edition 2.1

1. Denoting Concepts
2. Specifying Units of Measure
3. Attribute Value Metadata
4. Mapping Concepts

Part 4: Mapping Tables for EDCS Version 4.1 to FACC Edition 2.1

Part 5: Mapping API for EDCS Version 4.1 to FACC Edition 2.1

1. Mapping API Functions
2. Mapping API Data Structures
3. Mapping API Use Examples

The EDCS provides mechanisms to unambiguously specify objects used to model environmental concepts. This is accomplished by specifying a collection of nine EDCS Dictionaries of environmental concepts, and a functional interface to convert between numeric values given in different units of measure and scales. An EDCS Dictionary is a list of EDCS Dictionary Entries each of which specifies a single concept. Each EDCS Dictionary contains entries of a similar nature, however each entry is unique. Each EDCS Dictionary Entry consists of the following fields:

• definition
• label
• code
• reference type and references
• other EDCS Dictionary-dependent information such as value types, unit symbols, unit equivalence classes.

• EDCS Classification (EC) Dictionary
• EDCS Attribute (EA) Dictionary
• EDCS Attribute Value Metadata (EM) Dictionary
• EDCS Attribute Enumerant (EE) Dictionary
• EDCS Unit (EU) Dictionary
• EDCS Unit Scale (ES) Dictionary
• EDCS Unit Equivalence Class (EQ) Dictionary
• EDCS Organizational Schema (EO) Dictionary
• EDCS Group (EG) Dictionary

The EDCS Application Program Interface (API) supports conversion between real values given in different units of measure.

See the EDCS Website for more information on the structure and content of the EDCS.

Every concept In the EDCS Version 4.1 can be consistently denoted in two fashions: a label and a code.

• The label field of an EDCS Dictionary Entry is a compact and human-readable designator that is used to denote a concept. Labels may include the name or names for the concept. Labels:

  • uniquely denote a concept within a dictionary,
  • are a succinct expression of the concept it denotes,
  • are represented as a character string, and
  • are human readable.

• The code field of an EDCS Dictionary Entry is a compact, and not necessarily human-readable, designator that is used to denote a concept. Codes:

  • uniquely denote a concept within a dictionary,
  • are represented as an integer, and
  • are assigned sequentially in increasing order within an EDCS Dictionary, beginning at 1.

• There is a one-to-one relationship between labels and codes in the same EDCS Dictionary. Therefore, a label and a code may be used interchangeably to denote the same concept.

The EDCS Version 4.1 carefully separates the abstract specification of the EDCS (see ISO/IEC 18025 EDCS) from language-specific bindings (see ISO/IEC 18041-4 EDCS Language Bindings: Part 4: C).

As a result, in EDCS Version 4.1, three mechanisms exist for denoting EDCS concepts: the symbolic constant, the label, and the code.

For example, from files "edcs_types.h" and "edcs_class_iso.h" in the SDK Version 4.1 release:

   /*

    * GLOBAL CONSTANT: ECC_EXTRACTION_MINE

    *

    * Definition:

    *  An <EXCAVATION> made in the <TERRAIN> for the purpose of extracting

    *  and/or exploiting natural resources; an extraction mine.

    */



    #define ECC_EXTRACTION_MINE ((EDCS_Classification_Code)343)



   static const EDCS_Classification_Label_Entry

   EDCS_Classification_Labels[]=

   {...

    {ECC_EXTRACTION_MINE, "EXTRACTION_MINE"},

    ...

   }; /* EDCS_Classification_Labels */

The classification symbolic constant is "ECC_EXTRACTION_MINE", the label is "EXTRACTION_MINE", and the code is the EDCS_Classification_Code data type (an integer) of value 343.

Analogous mechanisms, and supporting structures and data types, exist for concepts in each of the other eight EDCS Dictionaries.

Thus:

• The symbolic constant can be used by programmers as a shorthand for the code, with the value of the code denoting the concept (e.g.) "Extraction Mine". The symbolic constants are defined in ISO/IEC 18041-4 EDCS Language Bindings: Part 4: C.

• The label is human-readable, and follows particular syntactic rules. It also denotes the concept (e.g.) "Extraction Mine", and is represented as a string with no prefix. Its string-value is defined in the EDCS abstract specification (ISO/IEC 18025 EDCS). The corresponding symbolic constant is derivable from the label through a set of rules documented in ISO/IEC 18041-4; in particular, the results of applying those rules are fully documented there.

• The code is an integer, and is intended for efficient software use. It also denotes the concept (e.g.) "Extraction Mine".

In summary:

• Symbolic constants are used by programmers as shorthand for codes.
• Labels are used by humans, and user interfaces.
• Codes are used by software.

- Scope of DIGEST

Digital Geographic Information (DGI) has evolved into an essential element in the planning and conduct of civil and military operations. The required data volume, demands, and data complexity dictate that multi-national agreements for digital data standards be established to assure compatibility. In support of this aim, the Digital Information Exchange Standard (DIGEST) standards define those aspects necessary to the exchange of DGI. They are as follows:

• the data structures to be supported (including spatial structure and metadata);
• a feature and attribute coding scheme;
• a format;
• exchange media; and
• administrative procedures.

• geographic feature geometry and feature attribute information;
• information concerning the appearance and status of the Earth's surface and its features in the electromagnetic spectrum, e.g. radar, infra-red; and
• other geographic information.

DIGEST standards enable interoperability and compatibility among national and multinational systems and users. They also support the increasing use of joint development programs. In fact, it is essential that geographic staffs involved in the development of national Geographic Information Systems are advised of the advantages of making their data structures and feature and attribute coding schemes compatible with these standards.

The intent of the DIGEST feature and attribute coding specification is to provide a standard scheme for documenting features and attributes necessary to distinguish environmental concepts commonly found in a Digital Geographic Information Systems and for the orderly exchange of such data. The specification, which is Part 4 of DIGEST, provides a common menu of features and attributes along with a standardized coding system. They are known collectively as the - Feature and Attribute Coding Catalogue (FACC) Data Dictionary.

FACC provides a means for encoding real-world entities or objects and concepts, including those which are not necessarily visible or have a tangible physical form (e.g., airspace). FACC describes the world in terms of features, attributes and attribute values. FACC does not specify the delineation or geometry of features. Attributes are the properties or characteristics associated with features. A standardized dictionary is required to support encoding in order to maximize interoperability and to understand the production, exchange, distribution, and exploitation of digital geographic data.

The FACC Data Dictionary allows for individual nations to define "national" features and attributes for cases where such features and attributes are not readily defined in the normative FACC Data Dictionary. National extensions are not specified within the normative FACC Data Dictionary, and may not support interoperability.

The FACC Data Dictionary can be modified and updated to keep pace with the dynamic technology improvements and changing requirements. National extensions may, if proposed and approved, be incorporated into future editions of the normative FACC Data Dictionary. Procedures for extending and modifying the FACC Data Dictionary are described in DIGEST Part 4, Clause 5.3. In this way, the FACC Data Dictionary may be extended so as to satisfy application requirements.

FACC Data Dictionary elements implement a specific coding structure. The coding structure does not specify criteria for feature and attribute selection or collection (e.g., positional accuracy, feature granularity). Selection and collection criteria are dependent upon user requirements, and determined by product specifications, data models, and database schemas.

Within FACC, each feature is identified (denoted) by a unique five-character code. The first character corresponds to the feature category and can have an alphabetic value from "A" to "Z". Currently there are ten major feature categories, including one category, "S", which has been reserved for dataset-specific features. The categories are as follows:

Each major feature category is further divided into subcategories identified by the second character of the five-character code containing an alphabetic value from "A" to "Z". Finally, the third, fourth, and fifth characters of the five-character feature code are a numeric value from 000 to 999. This value provides unique feature type identification within categories. Thus, all features must be identified by all five alphanumeric characters; e.g., the feature named "Building" is denoted by the code "AL015". Feature codes are listed in Annex A of the FACC Data Dictionary.

Attributes are used to describe characteristics of a feature, e.g., vegetation characteristic of a forested area (e.g., deciduous or evergreen). Each attribute is described by using an attribute code to represent the category of information. Each attribute is associated with a textual description, which provides a human readable dictionary definition for the attribute. Attribute value format statements provide a computer interpretation for the attribute value data type (e.g., real, alphanumeric) and attribute values give quantitative/qualitative meaning to the attribute.

Certain generic attribute concepts are often useful for value adding, or explaining missing attribution, and are pre-defined in FACC for all types of attributes. These concepts are: Null, Unknown, Unpopulated, Not Applicable, Multiple, and Other. DIGEST Part 2, Annex C, Clause C.2.3.4.4 describes the implementation of these generic attribute concepts.

"Coded" values (equivalent to enumerants in other coding schemes) may range from 0 to 999 and each value is given meaning by a name consisting of descriptive text. The value of such attributes is thus an (enumerant) code denoting the named description.

where code "BFC" denotes the attribute named "Building Function Category";
                    "I" indicates the data type of the coded value (a 4-byte integer for coded value attributes); and
                    "6" indicates the value of the attribute (the code denoting the named description "Hospital").

"Actual" values have a format (data type), one of: A (Alphanumeric), I (Integer), L (Lexical), R (Real Number) or S (Structured Text). Real values are typically measurements like height, width, etc. The units of measurement associated with an attribute are abbreviated according to the units of measurement codes defined in DIGEST Part 3, Clause 7 and incorporated into the specification of the attribute.

Data types or values for Lexical format attributes default to DIGEST Lexical level 0 or ASCII. However, when a LEX flag is present, a much wider range of character sets is available and it follows the ISO 10646 set of characters. Lexical values are described in detail in DIGEST Part 3, Clause 5.

where "ft" indicates "Feet" (Reference DIGEST Part 3, Clause 7), and "AMSL" indicates "Above Mean Sea Level".

Some example Actual Value Attribute specifications are:

  Code: "AIA"
  Name: "Airspace Identification Attribute"
  Definition: "A set of characters which enables an individual airspace to be uniquely identified."
  Value Domain: Lexical text string (15 characters).

  Code: "AOO"
  Name: "Angle of Orientation"
  Definition: "The angular distance measured from true north (0 deg) clockwise to the major axis of the feature. If the feature is square, the axis 0 through 89 deg shall be recorded. If the feature is circular, 360 deg shall be recorded."
  Value Domain: Integer between O and 360 inclusive, in increments of 1 degree.

  Code: "BEN"
  Name: "Basic Encyclopedia Number"
  Definition: "Unique number associated with a feature which is used to identify the feature in other national or intelligence data bases."
  Value Domain: ASCII text string (16 characters).

  Code: "C60"
  Name: "Rate of Current (IHO)"
  Definition: "Rate of current flow at tide reference level."
  Value Domain: Real, in Knots.

  Code: "PDR"
  Name: "Pedestrian Rate"
  Definition: "Number of pedestrians per time unit (this attribute utilizes the structured text approach), e.g. '10(persons)[per hour]'."
  Value Domain: Structured ASCII text (80 characters).

Additional information about Actual Value Attributes is contained in Annex B.

- Metadata coding

Attribute value format statements provide a computer interpretation for the attribute value data type (e.g., real, alphanumeric) and attribute values give quantitative/qualitative meaning to the attribute. Metadata are used to describe why the value of an attribute doesn't fall within its specified range of expected values. Metadata values which an attribute can take on are: "Unknown", "Multiple", "Unpopulated", "Not Applicable", and "Other". In addition "Null/No Value" is also defined. How these metadata concepts are encoded in FACC attribute values depends on the representation of that attribute. Table 5.2, below, from the FACC specification details these encodings.

Notes: The value for "Null" for each data type is defined in DIGEST, Part 2, Annex C, Table C-67.

1. If the length is one or two "-" or "--" should be used instead (refer to DIGEST, Part 2, Annex C, Clause C.2.5.4).

2. The Null value for a short integer is defined to be the bit pattern 10000000 00000000, which is equivalent to the maximum negative number in "two's complement number format". Therefore for a 16-bit length number, the corresponding value for Null is -32768.

3. The Null value for a long integer is defined to be the bit pattern 10000000 00000000 0000000 0000000, which is equivalent to the maximum negative number in "two's complement number format". Therefore for a 32-bit length number, the corresponding value for Null is -2147483648.

In FACC Edition 2.1, only a single mechanism exists for denoting feature (classification), attribute, and "coded" (enumerant) concepts: the code.

In summary:

• The code is a 5- (or 3-) character string, or an integer, intended primarily for efficient software use, but in practice might be a string that is (sometimes) human interpretable, e.g., the code "AA010" denoting the feature concept named "Mine".

The EDCS Version 4.1 is significantly different than FACC Edition 2.1 in the manner in which analogous concepts are denoted are denoted -- i.e., how each unique concept may be referenced by either humans or software. In EDCS Version 4.1, three mechanisms exist for denoting EDCS concepts: the symbolic constant, the label, and the code. These are all equivalent in some sense to the code in the FACC Edition 2.1.

• The EDCS Version 4.1 symbolic constant is a constant that can be used by programmers as a shorthand for the code.
  -- The FACC Edition 2.1 code is a "naked" string or integer. Although a C-language specific symbolic constant might be defined, the DIGEST FACC specifies no such functionality.

• The EDCS Version 4.1 label is human-readable, but follows particular syntactic rules and can be machine parsed. The corresponding symbolic constant is easily derivable from it.
  -- The FACC Edition 2.1 code is a compact string or integer. Although the codes for features (classification) and attributes (both strings) could be (and sometimes are) memorized, they are not especially convenient for such use for most users.

• The EDCS Version 4.1 code is functionally equivalent to the FACC Edition 2.1 code, however it is always an integer. In FACC Edition 2.1 codes it may be either a string or an integer.
  -- It is important to keep these differences in code types in mind. All EDCS Version 4.1 codes are positive, non-zero integers that are consecutively assigned within the scope of an EDCS Dictionary. The code whose value is the integer 1 will denote different concepts in different EDCS Dictionaries, just as the label whose value is "METER" will denote different concepts in different EDCS Dictionaries.

Example concepts from each EDCS Dictionary follow, first stating its label, and then specifying its symbolic constant, and finally specifying its code data type (always fundamentally an integer) and finally its value.

EDCS Dictionaries containing concepts comparable to those in FACC Edition 2.1:

• Classification (comparable to FACC Edition 2.1 Feature)
  EC Label: "ACCESS_ZONE"
  #define ECC_ACCESS_ZONE ((EDCS_Classification_Code) 1)



• Attribute (comparable to FACC Edition 2.1 Attribute)
  EA Label: "ACOUSTIC_AMBIENT_NOISE_SPECTRAL_MODEL"
  #define EAC_ACOUSTIC_AMBIENT_NOISE_SPECTRAL_MODEL ((EDCS_Attribute_Code) 9)



• Enumerant (comparable to FACC Edition 2.1 Coded Attribute Values)
  EE Label: "ANDES" (for EA Label: "ACOUSTIC_AMBIENT_NOISE_SPECTRAL_MODEL")
  #define EEC_ACAMBNSESPECMD_ANDES ((EAC_Acoustic_Ambient_Noise_Spectral_Model) 1)
  (Note that each EA is a separate data type.)

EDCS Dictionaries containing concepts not comparable to those in FACC Edition 2.1:

• Metadata (FACC handles these in a variety of fashions)
  EM Label: "VALUE_SPECIFIED"
  #define EVC_VALUE_SPECIFIED ((EDCS_Metadata_Code) 1)



• Unit (FACC binds these into the specification of individual attributes)
  EU Label: "AMP_PER_METRE"
  #define EUC_AMP_PER_METRE ((EDCS_Unit_Code) 1)



• Unit Equivalence Class (FACC has nothing comparable)
  EQ Label: "ABSORBED_DOSE"
  #define EQC_ABSORBED_DOSE ((EDCS_Unit_Equivalence_Code) 1)



• Scale (FACC has nothing comparable)
  ES Label: "YOTTA"
  #define ESC_YOTTA ((EDCS_Scale_Code) 1)



• Organizational Schema (FACC has nothing comparable)
  EO Label: "GENERAL"
  #define EOC_GENERAL ((EDCS_Organization_Schema_Code) 1)



• Group (FACC has nothing comparable)
  EG Label: "ABSTRACT_CONCEPT" (for EO Label: "GENERAL")
  #define EGC_GEN_ABSTRACT_CONCEPT ((EOC_General) 1)
  (Note that each EO is a separate data type.)

Units of measure in the FACC Edition 2.1 are bound into the specification of individual attributes. For example, the following two FACC Version 2.1 attributes differ only in their units of measure:

  Code: "HGF"
  Name: "Height Above Surface Level in Feet"
  Definition: "Distance measured from the lowest point of the base at ground or water level (downhill side/downstream side) to the tallest point of the feature."
  Value Domain: Integer, in Feet.

  Code: "HGT"
  Name: "Height Above Surface Level"
  Definition: "Distance measured from the lowest point of the base at ground or water level (downhill side/downstream side) to the tallest point of the feature."
  Value Domain: Integer, in Meters.

In the EDCS Version 4.1, concepts of units of measure have been given their own EDCS Dictionary and a separate EDCS Scale Dictionary supports the specification of the scale of the units of measure for an attribute value. Unit and scale labels are prefixed with "EUC_" and "ESC_", respectively, and their codes are represented as positive, non-zero consecutively assigned integers. Both the unit and scale are required in order to fully specify the meaning of the value of many quantitative attributes.

For example, to fully specify the value of the height of a mountain, in FACC Edition 2.1 either of attributes "HGF" or "HGT" could be used, however no other unit of measure for length, or different scale, could be used. In the EDCS Version 4.1, the same information would be specified for the attribute denoted by the label HEIGHT_ABOVE_SURFACE_LEVEL by simultaneously specifying two separate, orthogonal concepts: EUC_MILE and ESC_DECI, where EUC_MILE specifies the "mile" unit of measure and ESC_DECI specifies the "deci" scale of that unit of measure.

In EDCS Version 4.1, these concepts have been moved into the EDCS Attribute Value Metadata Dictionary, where they can be applied to attributes of any type. The labels of attribute value metadata concepts are prefixed with "EVC_" and their codes are represented as positive, non-zero, consecutively assigned integers.

For example, in FACC Edition 2.1:

  Attribute Code: "BFC"
  Value Domain:
    Code / Name: "0" "Unknown"

The equivalent, in EDCS Version 4.1, would be denoted as the pair of concepts:

  Attribute Label: "BUILDING_FUNCTION"
  Attribute Value Metadata Label: "MISSING"

Concepts encoded using the FACC Edition 2.1 are encoded differently using the EDCS Version 4.1, however essentially all concepts supported by FACC Edition 2.1 are also supported by EDCS Version 4.1, albeit sometimes using a combination of several EDCS Version 4.1 "atomic" concepts.

The tables at the end of this section document the mapping of concepts from EDCS Version 4.1 to FACC Edition 2.1. In the significant majority of cases, the concept mapping is one-to-one and direct. In some cases, however, the mapping is more complex.

These tables document the mappings for each of the concept types in EDCS Version 4.1 where there are equivalent concepts in FACC Edition 2.1: classifications, attributes, enumerants. In addition to listing the "EDCS 4.1 Symbolic Constant" for each concept, each table includes the columns "EDCS 4.1 Concept Mapping Type", "FACC 2.1 Concept Mapping Information", and "Additional Notes".

• The value of "EDCS 4.1 Concept Mapping Type" defines how to interpret and use the information listed in "FACC 2.1 Concept Mapping Information".


• The value of "Additional Notes" includes human-interpretable information that either clarifies the rationale behind the mapping type, or provides additional information for special cases.

The Concept Mapping Types are as follows:

• ONE_TO_ZERO - The EDCS Version 4.1 concept does not exist in the FACC Edition 2.1. The "FACC 2.1 Concept Mapping Information" column will be empty.
  
  Examples:
  • EDCS Classification does not map
    
    ECC_ARTIFICIAL_SATELLITE
    No mapping to the FACC Edition 2.1, because the FACC is limited to Mapping, Charting & Geodesy concepts.
    
  
  
  • EDCS Attribute does not map
    
    EAC_AIR_TEMPERATURE
    No mapping to the FACC Edition 2.1, because the FACC is limited to Mapping, Charting & Geodesy concepts.
    


• ONE_TO_ONE - The EDCS Version 4.1 concept is mapped directly to a single FACC Edition 2.1 concept. The "FACC 2.1 Concept Mapping Information" column will contain the code of the appropriate FACC Edition 2.1 concept.
  
  While the EDCS Version 4.1 Attribute Dictionary supports the ability for attributes which are COUNT, INTEGER, and REAL values to be both singletons, and intervals, the FACC Edition 2.1 only supports the ability to represent single values (either "integer" or "floating point") -- a change in datatype is effectively occuring. If the EDCS attribute concept may be interval-valued, and there is an appropriate FACC attribute concept which provides a mechanism for representing interval-values, then the mapping types of MAP_TO_CODED or INDETERMINATE are used. Otherwise, the interval-value can only be expressed using the metadata concept "Other" as defined in Table 5.2.
  
  Also, the EDCS Version 4.1 Attribute DIctionary allows for attribute concept instances to not have a value, but instead have an Attribute Value Metadata value. The FACC Edition 2.1 only consistently provides for metadata to be explicitly represented where a "coded list" is provided; for other representations (text, integer, and real) various non-unique encodings are specified, as in Table 5.2.
  
  Examples:
  • EDCS Version 4.1 Classification maps to FACC Edition 2.1 Feature
    
    ECC_EXTRACTION_MINE
    maps to
    AA010 (named "Mine")
    
  
  
  • EDCS Version 4.1 Attribute maps to FACC Edition 2.1 Attribute
    
    EAC_COLOUR_INTENSITY
    maps to
    CIC (named "Color Intensity Category")
    -- Note that this is a qualitative attribute for which the value is represented in EDCS Version 4.1 is as an ENUMERATION, whereas the representation in FACC Edition 2.1 is as "coded". "Coded" is comparable to ENUMERATION, however FACC Edition 2.1 "coded" includes metadata statements that are encoded differently in the EDCS Version 4.1. Each of the EAC_COLOUR_INTENSITY enumerants must be examined and mapped. In this particular case, each enumerant of EAC_COLOUR_INTENSITY has an exact mapping to a value of FACC Edition 2.1 attribute "CIC". Additionally, four possible Attribute Value Metadata values also have exact mappings. Other possible Attribute Value Metadata values do not; for example, EVC_MULTIPLE -- it is instead mapped to "CIC" with value "989", meaning "Multiple", based on Table 5.2.
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Edition 2.1 Attribute
    
    EAC_UPSTREAM_HEIGHT with any singleton-value
    maps to
    HGU (named "Height 2/Depth 2")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL, whereas the representation in FACC Edition 2.1 is as an "integer". A REAL can not be represented as an "integer" without loss of information; rounding will be required. The unit of measure in the EDCS Version 4.1 is specified using the Unit Equivalence Class EQC_LENGTH (for which EUC_METRE is preferred), while in FACC Edition 2.1 it is defined as "meter". These units of measure are commensurate; a unit of measure conversion may be required depending on the EU/ES of the actual value of EAC_UPSTREAM_HEIGHT. The precision of the EDCS representation of this concept will necessarily be lost as the corresponding FACC representation is necessarily "to the nearest meter".
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Edition 2.1 Attribute
    
    EAC_UPSTREAM_HEIGHT with any interval-value
    maps to
    HGU (named "Height 2/Depth 2")
        with value of -32768
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as an "integer". A REAL interval can not be represented as a single "integer". This is mapped to the metadata concept "Other" based on Table 5.2: -32768 (short integer).
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Edition 2.1 Attribute
    
    EAC_UPSTREAM_HEIGHT with no value and EVC_MISSING
    maps to
    HGU (named "Height 2/Depth 2")
        with value of -32768
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as an "integer". In this case, no value is present, although a metadata value exists. This is mapped to the metadata concept "Unknown" based on Table 5.2: -32768 (short integer).


• ONE_TO_ONE_QUALIFIED - The EDCS Version 4.1 concept is mapped directly, but it will be replaced with two or more FACC Edition 2.1 concepts. The "FACC 2.1 Concept Mapping Information" column will contain a comma-delimited list of codes of the appropriate FACC Edition 2.1 concepts.
  
  Examples:
  • EDCS Version 4.1 Classification maps to FACC Feature plus a FACC Attribute with a value
    
    ECC_FIRE_AND_POLICE_STATION
    maps to
    AL015 (named "Building") plus
        BFC (named "Building Function Category")
          with coded list value of 723 (named "Combined Fire and Police Station")
    -- Note that "AL015" is a broader concept than ECC_FIRE_AND_POLICE_STATION, so the additional "qualifying" FACC attribute of "BFC" is used to narrow the concept appropriately.
    
  
  
  • EDCS Version 4.1 Classification maps to FACC Feature plus two FACC Attributes with values
    
    ECC_JEWISH_TEMPLE
    maps to
    AL015 (named "Building") plus
        HWT (named "House of Worship Type")
          with coded list value of 16 (named "Temple") plus
        REL (named "Religious Denomination")
          with coded list value of 5 (named "Judaism")
    -- Note that "AL015" is a broader concept than ECC_JEWISH_TEMPLE, so the additional "qualifying" FACC attributes of "HWT" and "REL" are used to narrow the concept appropriately.
    


• MAP_TO_CODED - This occurs only in the case of mapping an EDCS Version 4.1 Attribute Dictionary concept to a FACC Edition 2.1 concept. The EDCS Version 4.1 attribute concept is mapped directly to a single FACC Edition 2.1 attribute concept.
  
  While the EDCS Edition 4.1 supports the ability for COUNT, INTEGER, and REAL values to be both singletons, and intervals, the FACC Edition 2.1 only supports the ability to represent single values (either "integer" or "floating point"). Situations in which the FACC intends to represent intervals are handled either by defining two related attributes (e.g., "DR1" and "DR2", handled using the SPECIAL_CASE mapping type), or by using a coded list attribute with a well-defined set of previously specified ranges (e.g., "BVL"). The "FACC 2.1 Concept Mapping Information" column will contain the code of the appropriate FACC Edition 2.1 concept. In addition, information in the EDCS Enumerant Mapping tables is used.
  
  The mapping type MAP_TO_CODED is used when the only appropriate FACC Edition attribute concept is "coded" (in EDCS terminology, ENUMERATION). This means that special logic is typically required for single-valued instances since, in general, "coded" attributes are not often used for single integer or real values; usualy inequalities on integer, or real, values are defined.
  
  The logic for handling such interval-valued EDCS attribute concepts is as follows:
  
  • Single-valued EDCS attribute instance (e.g., "3.1")
    Action: First, convert the value to account for ES/EU, then:
               Map to an exact matching single-value enumerant, if one exists;
               Else map to a ranged-value enumerant containing the single value (as a subset), if one exists;
               Else map to the "Other" concept of the ranged-value attribute.
    
  • Interval-valued EDCS attribute instance (e.g., "[4.5, 5.0)" )
    Action: First, convert the value to account for ES/EU, then:
               Map to an exact matching ranged-value enumerant, if one exists;
               Else map to a ranged-value enumerant containing the interval (as a subset), if one exists;
               Else map to the "Other" concept of the ranged-value attribute.
    
  • Non-valued EDCS attribute instance -- only metadata is present (e.g., EVC_MISSING)
    Action: Map to a corresponding ranged-enumerant attribute metadata code, if one exists;
               Else map based on Table 5.2.
  
  Examples:
  • EDCS Version 4.1 Attribute maps to FACC Attribute with a quantitative value
    
    EAC_WATER_TABLE_DEPTH with value "0.3" and EUC_METRE and ESC_UNI
    maps to
    YWT (named "Depth to Water Table") with coded list value of 1 (a ">0 and <=0.3")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL, whereas the representation in FACC Edition 2.1 is as a "coded list". There is no exact coded list item for the EDCS value provided, however the value falls within a range denoted by a coded list item.
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Attribute with a qualitative value
    
    EAC_WATER_TABLE_DEPTH with value "(0.3, 1.2]" and EUC_METRE and ESC_UNI
    maps to
    YWT (named "Depth to Water Table") with coded list value of 2 (a ">0.3 and <=1.2")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as a "coded list". There is an exact match.
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Attribute with a more general qualitative value
    
    EAC_WATER_TABLE_DEPTH with value "(0.5, 1.0]" and EUC_METRE and ESC_UNI
    maps to
    YWT (named "Depth to Water Table") with coded list value of 2 (a ">0.3 and <=1.2")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as a "coded list". While there is no exact match, there exists a ranged-value which is a superset of the EDCS attribute interval-value.
  
  
  
  • EDCS Version 4.1 Attribute with metadata maps to FACC Attribute with a qualitative value
    
    EAC_WATER_TABLE_DEPTH with no value and EVC_MISSING
    maps to
    YWT (named "Depth to Water Table") with coded list value of 0 (a "Unknown")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as a "coded list". However, there is no value in this instance, and instead an Attribute Value Metadata value is present.
  
  


• INDETERMINATE - This occurs only in the case of mapping an EDCS Version 4.1 Attribute Dictionary concept to a FACC Edition 2.1 concept, when more than one FACC Edition 2.1 concept may be appropriate -- depending on the instance value of the EDCS attribute.
  
  While the EDCS Edition 4.1 supports the ability for COUNT, INTEGER, and REAL values to be both singletons, and intervals, the FACC Edition 2.1 only supports the ability to represent single values (either "integer" or "floating point"). Situations in which the FACC intends to represent intervals are handled either by defining two related attributes (e.g., "DR1" and "DR2", handled using the SPECIAL_CASE mapping type), or by using a coded list attribute with a well-defined set of previously specified ranges (e.g., "BVL"). In some occasions, there may be more than one appropriate coded list attribute (e.g., "DW1", and "DW2"), or there may be an integer, or real, valued attribute and one or more coded list attributes (e.g., "DMB" and "BUD") which are appropriate.
  
  The "FACC 2.1 Concept Mapping Information" column will contain the code of the first appropriate FACC Edition 2.1 concept. In addition, information in the EDCS Enumerant Mapping tables is used.
  
  Also, the EDCS Edition 4.1 allows for attribute concept instances to not have a value, but instead have an Attribute Value Metadata value. The FACC Edition 2.1 only consistently provides for metadata to be explicitly represented where a "coded list" is provided; for other representations (text, integer, and real) various non-unique encodings are specified, as in Table 5.2.
  
  The logic for handling such EDCS attribute concepts is as follows:
  
  • Single-valued EDCS attribute instance (e.g., "3.1")
    Action: First, convert the value to account for ES/EU, then:
               Map to the indicated integer, or real, valued FACC attribute, if one exists;
               Else map to an exact matching single-value enumerant, if one exists;
               Else map to a ranged-value enumerant containing the single value (as a subset), if one exists;
               Else map to the "Other" concept of the ranged-value attribute.
    
  • Interval-valued EDCS attribute instance (e.g., "[4.5, 5.0)" )
    Action: First, convert the value to account for ES/EU, then:
               Map to an exact matching ranged-value enumerant, if one exists;
               Else map to a ranged-value enumerant containing the interval (as a subset), if one exists;
               Else map to the "Other" concept of an appropriate ranged-value attribute.
    Notes: If there is no exact match, and more than one ranged-value enumerant
                 specifying a superset of the interval exists, then map to the narrowest one.
               If more than one superset of the interval exists which is equally narrow
                 (and these are the narrowest that exist), map to the interval with the lower starting point.
  • Non-valued EDCS attribute instance -- only metadata is present (e.g., EVC_MISSING)
    Action: Map to a corresponding ranged-enumerant attribute metadata code, if one exists;
               Else map based on Table 5.2.
  
  Examples:
  • EDCS Version 4.1 Attribute maps to FACC Attribute with a quantitative value
    
    EAC_BRUSH_DENSITY with value "12.5" and EUC_PERCENT and ESC_UNI
    maps to
    DMB (named "Density Measure (Brush/Undergrowth)") with value of 12 (a "percent" "integer")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL, whereas the representation in FACC Edition 2.1 is as an "integer". A REAL can not be represented as an "integer" without loss of information; rounding will be required. The precision of the EDCS representation of this concept will necessarily be lost as the corresponding FACC representation is necessarily "to the nearest meter".
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Attribute with a qualitative value
    
    EAC_BRUSH_DENSITY with value "(5, 15]" and EUC_PERCENT and ESC_UNI
    maps to
    BUD (named "Brush/Undergrowth Density Code") with coded list value of 2 (a "> 5% and <= 15%")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as a "coded list".
  
  
  
  • EDCS Version 4.1 Attribute maps to FACC Attribute with a more general qualitative value
    
    EAC_BRUSH_DENSITY with value "(7.5, 12.5]" and EUC_PERCENT and ESC_UNI
    maps to
    BUD (named "Brush/Undergrowth Density Code") with coded list value of 2 (a "> 5% and <= 15%")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as a "coded list". While there is no exact match, there exists a ranged-value which is a superset of the EDCS attribute interval-value.
  
  
  
  • EDCS Version 4.1 Attribute with metadata maps to FACC Attribute with a qualitative value
    
    EAC_BRUSH_DENSITY with no value and EVC_MISSING
    maps to
    BUD (named "Brush/Undergrowth Density Code") with coded list value of 0 (a "Unknown")
    -- Note that this is a quantitative attribute for which the value is represented in EDCS Version 4.1 as a REAL interval, whereas the representation in FACC Edition 2.1 is as a "coded list". However, there is no value in this instance, and instead an Attribute Value Metadata value is present.
  
  
  
  
• SPECIAL_CASE - These cases will require some human reasoning to determine the best way to realize the EDCS Version 4.1 concept in FACC Edition 2.1. Both the "FACC 2.1 Concept Mapping Information" column and "Additional Notes" column contains information giving recommendations regarding how to handle the specific case.
  
  Examples:
  • Conversion to a non-commensurate unit of measure
    
    EAC_LEFT_BELOW_BANK_ANGLE
    maps to
    BWL (named "Below Water Bank Slope (Left)")
    -- Note that the Unit Equivalence Class of attribute EAC_LEFT_BELOW_BANK_ANGLE is EQC_PLANE_ANGLE, whereas the unit of measure of "BWL" is "percent" (rise/run). While the concepts are equivalent, the REAL angular value of EAC_LEFT_BELOW_BANK_ANGLE must be converted to a "short integer" slope value for "BWL". If the actual value of EAC_LEFT_BELOW_BANK_ANGLE is an interval, then while the conversion to slope can be made, ultimately no mapping is possible to a concept in FACC 2.1.
  
  
  
  • Deriving two single-valued attributes into a single interval-valued attribute
    
    EAC_WATER_DEPTH
    maps to
    DR3 (named "Depth Range With greater than 1 meter resolution - Value 1") and
    DR4 (named "Depth Range With greater than 1 meter resolution - Value 2")
    -- Note that if the attribute instance is interval-valued, then the interval must be parsed into its "DR3" and "DR4" components; if it is single-valued, then both "DR3" and "DR4" are set to that same value.

• Feature Code
  The 5-character feature code of a single FACC Edition 2.1 feature concept; there will be no additional information.
  
  
• Attribute Code
  The 3-character attribute code of a single FACC Edition 2.1 attribute concept; there will be no additional information.
  
  
• Attribute Code) with the coded value of (value) The 3-character attribute code of a single FACC Edition 2.1 attribute concept of type "coded list" with a specific (value).
  Examples:
        "APT with the CODED value of 7"
        "MAC with the CODED value of 999"
  
  

• Classification Mapping Table
• Attribute Mapping Table
• Enumerant Mapping Tables - Due to the sheer size of these tables, they have been split up alphabetically as follows:
  
  • Enumerants from A through H
  • Enumerants from I through P
  • Enumerants from Q through Z

This section describes the EDCS Version 3.x to FACC Edition 2.1 Mapping API functions, data structures, and use examples. The implementation of this mapping API is not included by default with the EDCS distribution but can be downloaded separately at www.sedris.org.

• EDCS 4.1 to FACC 2.1 Mapping Functions
  
  • EDCS_to FACC GetLibVersion
  • EDCS_to FACC InitMappingInfo
  • EDCS_to FACC MapAttributeCode
  • EDCS_to FACC MapAttributeWithValue
  • EDCS_to FACC MapClassificationCode
  • EDCS_to FACC PrintFACCValueType
  • EDCS_to FACC PrintMappingType
  • EDCS_to FACC ShutdownMappingInfo
  
  

• EDCS 4.1 to FACC 2.1 main mapping data structures:
  
  • EDCS_to_FACC_Attribute_Value_Structure
  • FACC_Attribute_Mapping_Structure
  • FACC_Attribute_With_Value_Mapping_Structure
  • FACC_Feature_Mapping_Structure
  • FACC_Mapping_Type_Code
  
  
• EDCS 4.1 common mapping data structures used in the main structures:
  
  • EDCS_LB_Value_Type
  • EDCS_Integer_Interval_Entry
  • EDCS_Integer_Unsigned_Interval_Entry
  • EDCS_Float_Interval_Entry
  • EDCS_Float_Entry


• FACC 2.1 specific mapping data structures used in the API:
  
  • FACC_2p1_Attribute_Code
  • FACC_2p1_Attribute_Integer_Code
  • FACC_2p1_Feature_Code
  • FACC_Attribute_With_Value
  • FACC_Value_Type
    

• Concept mapping from EDCS Version 4.1 Classifications
  • map_EDCS_class.c A sample program taking a list of EDCS 4.1 Classification symbolic constants on the command line, and printing out the associated FACC Edition 2.1 concept mapping information.
    
    Example: To retrieve mapping information for ECC_BUILDING and ECC_BUILT_UP_REGION:
    
        "map_EDCS_class ECC_BUILDING ECC_BUILT_UP_REGION"
    
    Example Output:
    
        "Mapping for EDCS Classification ECC_BUILDING was ONE_TO_ONE:
            FACC Feature Code: AL015
    
         Mapping for EDCS Classification ECC_BUILT_UP_REGION was ONE_TO_ONE:
            FACC Feature Code: AL020"
    
  
  
• Concept mapping from EDCS Version 4.1 attributes
  • map_EDCS_attribute.c A sample program taking a list of EDCS Version 4.1 attribute symbolic constants on the command line, and printing out the associated FACC Edition 2.1 concept mapping information.
    
    Example: To retrieve mapping information for EAC_HEIGHT_ABOVE_SURFACE_LEVEL and EAC_WIDTH:
    
        "map_EDCS_attribute EAC_HEIGHT_ABOVE_SURFACE_LEVEL EAC_WIDTH"
    
    Example Output:
    
        "Mapping for EDCS Attribute EAC_HEIGHT_ABOVE_SURFACE_LEVEL was INDETERMINATE.  This means that it maps to different FACC Attributes depending on the value associated with it. The mapping for non-interval and non-metadata values is:
                 FACC Attribute: HGT
                 FACC Value Type: SHORT INTEGER
                 FACC Expected Unit: EUC_METRE
                 FACC Expected Scale: ESC_UNI
                 Mapping Notes: Changed datatype from REAL to "Integer". May also map to HTR if interval-valued or metadata.
    
        Mapping for EDCS Attribute EAC_WIDTH was ONE to ONE:
                FACC Attribute: WGP
                FACC Value Type: FLOAT
                FACC Expected Unit: EUC_METRE
                FACC Expected Scale: ESC_UNI"
    
  
  
• Concept mapping from EDCS Version 4.1 enumerants
  • map_EDCS_enumerant.c A sample program taking a list of EDCS Version 4.1 enumerant symbolic constants on the command line, and printing out the associated FACC Edition 2.1 concept mapping information.
    
    Example: To find mapping information for EEC_BLDGFN_SHOPPING_CENTRE and EEC_TERMRPHTY_SAND_DUNES:
    
        "map_EDCS_enumerant EEC_BLDGFN_SHOPPING_CENTRE EEC_TERMRPHTY_SAND_DUNES"
    
    Example Output:
    
        "Mapping for EDCS Enumerant EEC_BLDGFN_SHOPPING_CENTRE was ONE to ONE:
                   FACC Attribute: BFC
                   FACC Value Type: CODED
                   FACC Coded Value: 122
    
         Mapping for EDCS Enumerant EEC_TERMRPHTY_SAND_DUNES was ONE to ONE:
                   FACC Attribute: SRD
                   FACC Value Type: CODED
                   FACC Coded Value: 38"
    
  
  
• Concept mapping from EDCS Version 4.1 attributes with interval values
  • map_EDCS_attribute_value.c A sample program taking a space delimited list of EDCS Version 4.1 attribute symbolic constant and value specification pairs on the command line, and printing out the associated FACC Edition 2.1 concept mapping information.  Handles interval, boolean, metadata, and single values.
    
    Example: To find mapping information for EAC_BRUSH_DENSITY with the interval value [0, 5] and the EU PERCENT with ES UNI, and EAC_RIGHT_BANK_SLOPE with the interval value [15, 30] and the EU PERCENT with ES UNI, and EAC_TREE_SPACING with the real value 5.0 and the EU METRE with ES UNI, and EAC_CAPACITY with the metadata value of EVC_MISSING:
    
        "map_EDCS_attribute_value "EAC_BRUSH_DENSITY [0, 5] EUC_PERCENT ESC_UNI" "EAC_RIGHT_BANK_SLOPE [15, 30] EUC_PERCENT ESC_UNI" "EAC_TREE_SPACING 5.0 EUC_METRE ESC_UNI" "EAC_CAPACITY EVC_MISSING""
    
    Example Output:
    
    "Mapping 1: "EAC_BRUSH_DENSITY [0, 5] EUC_PERCENT ESC_UNI"
     Mapping was ONE to ONE:
        FACC Attribute: BUD
        FACC Value Type: CODED
        FACC Coded Value: 1
        Notes: <= 5%.
    
    Mapping 2: "EAC_RIGHT_BANK_SLOPE [15, 30] EUC_PERCENT ESC_UNI"
    Mapping was ONE to ONE:
        FACC Attribute: SR1
        FACC Value Type: CODED
        FACC Coded Value: 1
        Notes: <= 30%.
    
    Mapping 3: "EAC_TREE_SPACING 5.0 EUC_METRE ESC_UNI"
    Mapping was ONE to ONE:
        FACC Attribute: TSD
        FACC Value Type: FLOAT
        FACC Float Value: 5.000000
        Notes: May also map to TS1/TS2/TS3 if interval-valued or metadata.
    
    Mapping 4: "EAC_CAPACITY EVC_MISSING"
    Mapping was ONE to ONE:
        FACC Attribute: CAP
        FACC Value Type: TEXT
        FACC Text Value: UNK"