This requirement is fulfilled by including a geographic description (GeographicDescription) as a clear, textual description of the data set's geographical extent.
Rule
Each ICAO obstacle data set shall be provided together with metadata giving the geographical extent of the data set.
Recommendation
Each ICAO data set, other than obstacle data sets, should be provided together with metadata giving the geographical extent of the data set.
Best practice
This requirement is fulfilled by including:
- GeographicDescription; and
- GeographicBoundingBox or BoundingPolygon.
The GeographicDescription gives a clear, textual description of the data set's geographical extent. It can be seen as an summary of the GeographicalBoundingBox or BoundingPolygon for operational experts.
The inclusion of a bounding box or polygon is a good practice in the GIS world. They are useful for applications that represent the data graphically, to set the initial window size. They are also facilitate the evaluation of the geographical coverage of a data set without having to parse and decode the full data set.
Geographic Description
Requirement | Reference | DS-META-007 |
Element Name | Geographical extent of the data set | |
Obligation / Condition | Mandatory. One of the three options must be provided. | |
Multiplicity | 1..* | |
ISO 19115 (2003) | Number | 349 |
Name | geographicIdentifier | |
Definition | identifier used to represent a geographic area | |
XPath | gmd:MD_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicDescription/gmd:MD_Identifier/gmd:code/gco:CharacterString | |
Data type | CharacterString | |
Domain | Free Text | |
Example | Belgium and Luxembourg | |
Implementing Instructions | - |
<gmd:MD_Metadata> ... <gmd:identificationInfo> <gmd:MD_DataIdentification> <gmd:extent> <gmd:EX_Extent> <gmd:geographicElement> <gmd:EX_GeographicDescription> <gmd:geographicIdentifier> <gmd:MD_Identifier> <gmd:code><gco:CharacterString>Belgium and Luxembourg</gco:CharacterString></gmd:code> </gmd:MD_Identifier> </gmd:geographicIdentifier> </gmd:EX_GeographicDescription> </gmd:geographicElement> </gmd:EX_Extent> </gmd:extent> </gmd:MD_DataIdentification> </gmd:identificationInfo> ... </gmd:MD_Metadata>
Geographic Bounding Box
Requirement | Reference | DS-META-007 |
Element Name | Geographical extent of the data set | |
Obligation / Condition | Mandatory. One of the three options must be provided. | |
Multiplicity | 1..* | |
ISO 19115 | Number | 344 |
Name | westBoundLongitude | |
Definition | Western-most coordinate of the limit of the dataset extent, expressed in longitude in decimal degrees (positive east) | |
XPath | gmd:MD_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicBoundingBox/gmd:westBoundLongitude/gco:Decimal | |
Data type | Decimal | |
Domain | -180.00 <= West Bounding Longitude Value <= 180.00 | |
Example | 3.93 | |
ISO 19115 | Number | 345 |
Name | eastBoundLongitude | |
Definition | Eastern-most coordinate of the limit of the dataset extent, expressed in longitude in decimal degrees (positive east) | |
XPath | gmd:MD_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicBoundingBox/gmd:eastBoundLongitude/gco:Decimal | |
Data type | Decimal | |
Domain | -180.00 <= East Bounding Longitude Value <= 180.00 | |
Example | 7.57 | |
ISO 19115 | Number | 346 |
Name | southBoundLatitude | |
Definition | Southern-most coordinate of the limit of the dataset extent, expressed in latitude in decimal degrees (positive north) | |
XPath | gmd:MD_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicBoundingBox/gmd:southBoundLatitude/gco:Decimal | |
Data type | Decimal | |
Domain | -90.00 <= South Bounding Latitude Value <= North Bounding Latitude Value | |
Example | 52.10 | |
ISO 19115 | Number | 347 |
Name | northBoundLatitude | |
Definition | Northern-most coordinate of the limit of the dataset extent, expressed in latitude in decimal degrees (positive north) | |
XPath | gmd:MD_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicBoundingBox/gmd:northBoundLatitude/gco:Decimal | |
Data type | Decimal | |
Domain | South Bounding Latitude Value <= North Bounding Latitude Value <= 90.00 | |
Example | 54.10 | |
Implementing Instructions | - |
<gmd:MD_Metadata> ... <gmd:identificationInfo> <gmd:MD_DataIdentification> <gmd:extent> <gmd:EX_Extent> <gmd:geographicElement> <gmd:EX_GeographicBoundingBox> <gmd:westBoundLongitude><gco:Decimal>3.93</gco:Decimal></gmd:westBoundLongitude> <gmd:eastBoundLongitude><gco:Decimal>7.57</gco:Decimal></gmd:eastBoundLongitude> <gmd:southBoundLatitude><gco:Decimal>52.10</gco:Decimal></gmd:southBoundLatitude> <gmd:northBoundLatitude><gco:Decimal>54.10</gco:Decimal></gmd:northBoundLatitude> </gmd:EX_GeographicBoundingBox> </gmd:geographicElement> </gmd:EX_Extent> </gmd:extent> </gmd:MD_DataIdentification> </gmd:identificationInfo> ... </gmd:MD_Metadata>
BoundingPolygon
Requirement | Reference | DS-META-007 |
Element Name | Geographical extent of the data set | |
Obligation / Condition | Mandatory. One of the three options must be provided. | |
Multiplicity | 1..* | |
ISO 19115 (2003) | Number | 342 |
Name | polygon | |
Definition | set of points defining the bounding polygon | |
XPath | gmd:MetaData/gmd:identificationInfo/gmd:DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_BoundingPolygon/gmd:polygon | |
Data type | Class | |
Domain | GM_Object | |
Example | 30 30 30 40 60 40 60 30 | |
Implementing Instructions | - |
<gmd:MD_Metadata> ... <gmd:identificationInfo> <gmd:DataIdentification> <gmd:extent> <gmd:geographicElement> <gmd:EX_BoundingPolygon> <gmd:polygon> - various options exist for completing the polygon. Please refer to the "Guidance and Profile of GML for use with Aviation Data".</gmd:polygon> </gmd:EX_BoundingPolygon> </gmd:geographicElement> </gmd:extent> </gmd:DataIdentification> <gmd:identificationInfo> ... </gmd:MD_Metadata>