The contributing hub must provide three services:
publication of ISO19115-3 metadata through a catalogue service - nominally GeoNetwork
publication of Web Mapping Service and Web Coverage Service according to AusSeabed protocols
direct download of Local Hub products through HTTP protocol
The contributing hub must also provide a description of their holdings in an Excel format that can be read by the Exploring For The Future Portal.
Publication of ISO19115-3 metadata
Most large organisations that distribute spatial data catalogue the existence of that data using a metadata catalogue system such as GeoNetwork. AusSeabed contributing hubs must provide a catalogue that can be harvested by AODN (and others) using GeoNetwork. AusSeabed requires that metadata entries be systematised to support downstream search and filter.
General Background
There are several metadata standards for describing spatial data, but ISO19115 continues to grow in popularity. The standard itself provides a wide range of flexibility in the forms of XML that it accepts. It is rarely possible for a system to understand the semantics of every component of XML that meets the standard. Likewise, the standard permits different ways of representing the same information. What has emerged are profiles of the ISO19115 that have agreed meaning among subsets of the spatial community. These can also include variations such as additional mandatory fields. In AusSeabed’s case the most notable is the marine community profile (ISO19115-3) that is designed for marine purposes (most notably documenting marine specimen samples). Worthy of similar mention is GA’s Community Profile that forces some metadata tags to be mandatory.
Technical Details
Geonetwork provides at least three method of editing metadata: a) a simple interface; b) the full interface; and c) an XML editor. Most metadata can be entered in the simple interface; however, a number of fields require the full editing interface or XML editor (or import) including:
Attribute | Location in XML | Interface |
|---|---|---|
Abstract | IdentificationInfo/Abstract | Simple |
Title | IdentificationInfo/Citation/Title | Simple |
Keyword (marine) | <mri:descriptiveKeywords>
<mri:MD_Keywords>
<mri:keyword>
<gco:CharacterString>marine</gco:CharacterString>
</mri:keyword>
<mri:type>
<mri:MD_KeywordTypeCode codeList="codeListLocation#MD_KeywordTypeCode" codeListValue="theme"/>
</mri:type>
</mri:MD_Keywords>
</mri:descriptiveKeywords>
| Simple |
Start Date | IdentificationInfo/Extent/TemporalExtent/TimePeriod/BeginPosition | Simple |
End Date | IdentificationInfo/Extent/TemporalExtent/TimePeriod/EndPosition | Simple |
Vessel (for surveys, not compilations) | Acquisition Information/Platform/Identifier | Full/XML |
Instrument (for surveys, not compilations) | Acquisition Information/Platform/Instrument/Identifier | Full/XML |
Vessel and instrument should also link to a valid vocabulary entry in a vocabulary server. E.g.
<mcc:code> <gcx:Anchor xlink:href="http://vocab.nerc.ac.uk/collection/C17/current/09SS">Southern Surveyor</gcx:Anchor> </mcc:code>
Likewise, start and end ports should link to a valid vocabulary entry. E.g. SeaDataNet Ports:
http://vocab.nerc.ac.uk/collection/C38/current/BSH244/
AusSeabed protocols for publishing Web Mapping Service and Web Coverage Services
For consistency, L3 products need to be presented through web services in the same way. Each L3 product served through a Web Mapping Service (WMS) must be presented as a group layer:
Presentation Order | Product | Type | Style |
|---|---|---|---|
Bottom | Extent Polygon | Polygon | |
Middle | Hillshade | Raster | |
Top | Bathymetry | Raster |
Naming of layers
The layers should follow a consistent form. The form chosen for GA’s holdings is:
{Location}_{Product Type}_{Publication Date}_{Resolution}{Product Code}
Element | Value |
Location | Name of survey feature |
Product Type | Bathymetry (for extension to Backscatter) |
Publication Date | Year of publication (with publication style referencing when multiple publications in the same year) |
Resolution (Horizontal) | 1m (with metric unit name attached). Where multiple resolution are present this should be represented as: {number}{unit} - {number}{unit}. For example, 2m - 25m. Units are in metric length (where reasonable). |
Product Code | Empty for group presentation layer, “_OV” for bathymetry, “_HS” for hillshade, “_Coverage_L3” for coverage extent. |
Special characters are replaced with underscores.
For example:
Beagle_Commonwealth_Marine_Reserve_Bathymetry_2018_1m_OV
Element | Value |
Location | Beagle Commonwealth Marine Reserve |
Product Type | Bathymetry |
Publication Date | 2018 |
Resolution | 1m |
Product Code | OV |
Bathymetry
All GeoTIFF images must be provided in Cloud Optimised form. For large images we have image overlays at 2 4 8 16 32 scales.
Hillshade
The hillshade must be produced with azimuth 30 degrees, altitude 45 degrees and z scaling factor of 2. For geographic projection images, a scaling factor of 111120 must be applied.
Extent Polygon
The extent polygon must contain metadata attributes of the layer (in any order):
Field | Example | |
|---|---|---|
AREA_KM2 | Area covered by the survey in square kilometres | 6654 |
BATHY_TYPE | Type of product (e.g. Multibeam, Backscatter) | Multibeam |
NAME | Title of product | Mentelle Basin Survey (GA-0293/SS08/2005) - Bathymetry grids |
START_DATE | Date that acquisition commenced | 28/09/2005 |
END_DATE | Date that acquisition completed | 19/10/2005 |
VESSEL | Name of Vessel | Southern Surveyor |
INSTRUMENT | Name of Instrument | Kongsberg EM300 |
BATHY_URL | Web resolvable link to bathymetry data | |
META_URL | Web resolvable link to metadata (persistent identifier preferred) |
For surveys, the follow attributes are to be used:
Field | Example | |
|---|---|---|
START_PORT | The port where the vessel departed | Hobart, Australia |
END_PORT | The port where the vessel arrived | Hobart, Australia |
Direct download of Local Hub products
All L3 products must be downloadable using standard HTTP protocols (http/https). They should have a consistent file format. Individual AusSeabed Data Hubs may have limitations on their capacity to define file names (i.e. because of integration with other systems). However, where they do have capacity to define names, the following convention may be useful:
{Location}_{Product Type}_{Vertical Datum}_{Publication Date}_{Resolution}_{Product Identifier?}_{Version Identifier}_{Format Extension}
We would want to replace any special characters with _, and version information could simply be the date in an appropriate text format.
Element | Value |
Location | Name of survey feature |
Product Type | Bathymetry (for extension to Backscatter) |
Publication Date | Year of publication (with publication style referencing when multiple publications in the same year) |
Resolution (Horizontal) | 1m (with metric unit name attached) |
Vertical Datum | ‘Ellipsoid’, ‘MSL’, ‘LAT’ (note ellipsoid rather than WGS84 to avoid confusion with horizontal projection) |
Product Identifier | For non-GA records, an identifier that is used in other catalogues |
Version Identifier | An appropriate mechanism for distinguishing between versions. At GA, the plan is to use a date timestamp in ISO format – universal time without separators. |
Format Extension | A standard string defining the format of the product – e.g. “cog.tif” for cloud optimised geotiff. |
For examples:
Beagle_Commonwealth_Marine_Reserve_Bathymetry_Ellipsoid_2018_3m_20200827T053422Z_cog.tif
Element | Value |
Location | Beagle Commonwealth Marine Reserve |
Product Type | Bathymetry |
Vertical Datum | Ellipsoid |
Publication Date | 2018 |
Resolution | 3m |
Version Identifier | 20200827T053422Z - The product generated at Thu Aug 27 2020 15:34:22 GMT+1000 (Australian Eastern Standard Time). |
Identifier | N/A |
Description of holdings for inclusion in EFTF Portal
Portal Category | Definition | Example |
PRIMARY THEME | The first level category in the Portal (shown in the panel on the left hand side) | Elevation and Depth |
SECONDARY THEME | The second level category in the Portal (shown in the panel on the left hand side) | Bathymetry - Survey |
NAME | Name of the layer (see conventions below) | Apollo Bay Bathymetry 2020 0.5m |
WMS LAYER NAMES | Comma separated list of layers should be shown under this heading (should point to one or more group layers) | ausseabed:Apollo_Bay_Bathymetry_2020_0_5m |
WCS LAYER NAMES | Comma separated list of bathymetry layers that have WCS endpoints | ausseabed:Apollo_Bay_City_of_Rayville_Bathymetry_2020_0_5m_OV |
TYPE | Type of service - always WMS? | WMS |
DESCRIPTION | Should be empty which means it is picked up from the WMS Service GetCapabilities document | empty |
TILECACHEURL | If there is a tilecache url | null |
SINGLETILE | Openlayers and WMS can work nicely together if single tile is set to true. | FALSE |
WMS URL | Url of the WMS service | |
WCS URL | Url of the WCS service | |
CSV URL | Ignore - for urls of CSV products | empty |
LEGEND URL | Ignore - legend should be defined by WMS service | empty |
xmin | If this is blank, the portal will use the WMS service’s get capabilities to calculate extent. It may still be required for group layers. | 143.4895 |
ymin | If this is blank, the portal will use the WMS service’s get capabilities to calculate extent. It may still be required for group layers. | -38.993 |
xmax | If this is blank, the portal will use the WMS service’s get capabilities to calculate extent. It may still be required for group layers. | 143.5608 |
ymax | If this is blank, the portal will use the WMS service’s get capabilities to calculate extent. It may still be required for group layers. | -38.9669 |
GEOMETRY | This should be RASTER for all raster bathymetry | RASTER |
POLYGON KEY | empty | |
TIME SERIES | null | |
PERSONA | This should be Marine for all AusSeabed products | Marine |
JSON | This is a placeholder for the excel spreadsheet to generate the values | empty |
PRODUCTION | NO for nonprod.portal.ga.gov.au, YES for portal.ga.gov.au as well | NO |
FILTER JSON | empty | |
INITIALISE_FOR_PERSONAS | Show this layer switched on by default for a particular persona - leave empty | empty |
RELATED_RECORDS | empty |
Display names on the portal
{Location} {Product Type} {Publication Date} {Resolution} ({Organisation if not GA}) [{Identifier}]
Element | Value |
Location | Name of survey feature |
Product Type | Bathymetry (for extension to Backscatter) |
Publication Date | Year of publication (with publication style referencing when multiple publications in the same year) |
Resolution (Horizontal) | 1m (with metric unit name attached) |
Organisation | For organisations other than Geoscience Australia use a short name (e.g. GA) |
Identifier | For non-GA records, an identifier that is used in other catalogues |
Examples:
Beagle Commonwealth Marine Reserve Bathymetry 2018 1m
Element | Value |
Location | Beagle Commonwealth Marine Reserve |
Product Type | Bathymetry |
Publication Date | 2018 |
Resolution | 1m |
Organisation | GA |
Identifier | N/A |
Boags Marine Reserve Bathymetry 2018 1m (CSIRO) bf2018_v01
Element | Value |
Location | Boags Marine Reserve |
Product Type | Bathymetry |
Publication Date | 2018 |
Resolution | 1m |
Organisation | CSIRO |
Identifier | bf2018_v01 |