TemperateReefBase Geonetwork Catalogue
Weddell seal reporting grid of the Vestfold Hills, Antarctica
This is a digital version of the grid reference map used to plot all sightings of Weddell seals in the Vestfold Hills. The point of origin is the same as the original map and each grid cell is numbered with the same numbering scheme. This can be used to plot any data using the same numbering scheme by joining (ArcInfo) or linking (ArcView) records to this coverage's polygon attribute table (pat) through the item GRIDREF.
The original map was a 1:100 000 map of the Vestfolds, provided by Harry Burton, with a grid drawn over it. The grid references were given as either six or four figure values on which field scientists are to plot their data.
This map has the following Antarctic Division drawing reference number:
M/75/05A
Some research with John Cox revealed that this grid was drawn up over a map digitised from another map with the following specifications:
Scale 1: 100 000
Date: 1958 (reprinted 1972)
Projection: Polyconic
Published by: Division of National Mapping, Canberra
Reference number: NMP/58/084
Data are referenced to a 'grid' of 1 minute spacing in x axis and 30 second spacing in y axis. The point of origin is apparently 68 20 S 77 48 E. There are 45 rows and 47 columns.
The 'grid reference' is in fact in geographic coordinates (but using arbitrary units) so the projection of the original map became irrelevant.
The procedure adopted to create a new digital grid was as follows:
(Carried out in Arc/Info)
1. Generate a coverage using the original 'grid references'.
2. Tics were also generated using the corners of the 'grid reference' system.
3. A new coverage was created with tics at the same locations but given the true latitude/longitude vales.
4. The original coverage was then transformed to the new coverage based on the new tic values.
5. The new coverage was then projected from geographic coordinates to UTM metres.
The data locations were then viewed in Arc/Info using a coverage of the coastline supplied by the Mapping Officer, Antarctic Division. This had previously been determined to be in the UTM projection.
An offset was clearly visible between the data locations and the coastline. In order to determine whether the offset was more or less uniform, ten locations were plotted from the original data onto the original map using the 'grid'. Finally a manual corrected was made by moving all the data locations by a uniform distance of 508 metres north and 68 metres west.
Information from John van den Hoff, February 2019:
The grid cells were originally labelled from 1 to 47 along the x axis and 1 to 45 along the y axis. The four digit values in the GRIDREF field of the attribute table are the x value followed by the y value.
To avoid confusion between x and y values, the grid was later revised so that the y values were prefixed with a ‘1’ so for example 01 became 101. The GRIDREF_X and GRIDREF_Y fields have the x and y values of the revised grid.
This needs to be kept in mind when data is sourced from field books.
The map shows the revised grid.
Simple
Identification info
- Alternate title
- Weddell seal reporting grid of the Vestfold Hills, Antarctica
- Date (Publication)
- 2019-02-28
- Edition
- 2
- Citation identifier
-
Dataset DOI
- Title
- Information and documentation - Digital object identifier system
- Date (Publication)
- 2012-04-23
- Citation identifier
- ISO 26324:2012
- Citation identifier
- doi:10.4225/15/59dc39c4610f6
Originator
Publisher
Principal investigator
Principal investigator
Principal investigator
Collaborator
- Name
- CAASM Metadata
- Status
- Completed
Custodian
- Topic category
-
- Biota
- Oceans
Extent
))
Extent
- Description
- Temporal Coverage
Temporal extent
- TimePeriod
- 1989-09-30 1990-03-31
- NASA/GCMD Earth Science Keywords
-
- EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > TERRESTRIAL ECOSYSTEMS > ISLANDS
- EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MAMMALS > CARNIVORES > SEALS/SEA LIONS/WALRUSES
- NASA/GCMD Earth Science Keywords
-
- Computer > Computer
- NASA/GCMD Earth Science Keywords
-
- MAPS
- NASA/GCMD Earth Science Keywords
-
- AMD/AU
- CEOS
- AMD
- NASA/GCMD Earth Science Keywords
-
- CONTINENT > ANTARCTICA
- GEOGRAPHIC REGION > POLAR
Resource constraints
- Use limitation
- This metadata record is publicly available.
Resource constraints
- Access constraints
- licence
- Other constraints
- These data are publicly available for download from the provided URL. A link to the map in the map catalogue is also provided.
Resource constraints
- File type
- Portable Network Graphic
- Title
- Attribution 4.0 International (CC BY 4.0)
- Website
-
https://creativecommons.org/licenses/by/4.0/legalcode
Legal code for Creative Commons by Attribution 4.0 International license
- Use constraints
- licence
- Other constraints
- This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=Wed_map when using these data.
- Language
- English
- Character encoding
- UTF8
Distribution Information
Distributor
Distributor
Distributor
- Fees
- Free
- Planned available datetime
- 2019-02-28T00:00:00
- Units of distribution
- kb
- Transfer size
- 85
- Distribution format
-
- Shapefiles
- OnLine resource
-
GET DATA
Download the dataset
- OnLine resource
-
PROJECT HOME PAGE
Public information for ASAC project 89
- OnLine resource
-
PROJECT HOME PAGE
Public information for ASAC project 95
- OnLine resource
-
VIEW RELATED INFORMATION
Vestfold Hills: Map for Weddell Seal sightings
- OnLine resource
-
VIEW RELATED INFORMATION
Citation reference for this metadata record and dataset
Resource lineage
- Statement
- Positional Accuracy 1 m to 10 m There are several sources of error: 1. Inaccuracies in the original map, both in the shape of the coastline and in the geodetic framework. In 1958, the geodetic control for the aerial photography would have been done using astronomical observations. 2. Inaccuracies in the 'modern' (UTM) coastline. There are known to be inaccuracies in the map from which this was digitised and there are question marks about the quality of the digitising. 3. Inaccuracies in plotting the location data in the field which were presumably done by estimating position from local landmarks rather than by measurement eg compass bearing. 4. The correction of the offset manually is only a 'best fit' for all points. Values provided in temporal coverage are approximate only.
- Hierarchy level
- Dataset
- Maintenance and update frequency
- As needed
- Maintenance note
- 2017-10-10 - record updated by Dave Connell to link data recovered by David Smith. 2019-02-28 - record updated by David Smith after discussion with John van den Hoff.
Metadata
- Metadata identifier
- string/Wed_map
- Language
- English
- Character encoding
- UTF8
Author
Sponsor
Owner
- Title
- Parent Metadata Record
- Citation identifier
- AADC-00048
Type of resource
- Resource scope
- Dataset
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Citation identifier
- ca02315a-f969-40c3-bd1b-a07c3d78000e
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Date (Last Revision)
- 2019-02-28T16:08:08
Identifier
- Description
- metadata.extraction_date
Alternative metadata reference
- Title
- gov.nasa.gsfc.gcmd
- Citation identifier
- 8.6
- Metadata linkage
-
http://data.aad.gov.au/metadata/records/Wed_map
Point of truth for the metadata record
- Date info (Creation)
- 2000-07-03T00:00:00
- Date info (Last Update)
- 2019-02-28
Metadata standard
- Title
- ISO 19115-3
- Edition
- 2014
- Other citation details
- Version 1
- Title
- DIF to ISO 19115-1 Profile
Overviews
Spatial extent
Provided by
