Extraction of the GMRT grid for the Caribbean region

Ryan, W.B.F., S.M. Carbotte, J.O. Coplan, S. O'Hara, A. Melkonian, R. Arko, R.A. Weissel, V. Ferrini, A. Goodwillie, F. Nitsche, J. Bonczkowski, and R. Zemsky (2009), Global Multi-Resolution Topography synthesis, Geochem. Geophys. Geosyst., 10, Q03014, doi: 10.1029/2008GC002332


Extraction of the GMRT grid for the Caribbean region of EMODnet bathymetry.

The extraction is updated in June 2024.


GMRT overview from https://www.gmrt.org/about/index.php

The Global Multi-Resolution Topography (GMRT) Synthesis is a multi-resolution Digital Elevation Model (DEM) maintained in three projections and managed with a scalable global architecture that offers infrastructure for accessing the DEM as grids, images, points and profiles. A mask layer is available that highlights the location of high-resolution data. Most curatorial effort for GMRT is focused on cleaning and processing ship-based multibeam sonar data acquired by the US Academic Research Fleet (ARF) so they can be gridded at their full spatial resolution (~100m in the deep sea). These data are seamlessly overlain on lower resolution observed and predicted bathymetry data and are integrated with terrestrial elevation data to deliver to users the best resolution data that have been curated for a particular area area of interest.

 
Citation proposal
Lamont-Doherty Earth Observatory, Columbia University. Extraction of the GMRT grid for the Caribbean region. https://services.mspdata.eu:/geonetwork/srv/api/records/SDN_CPRD_1384_GMRT2022_Caribbean

Simple

Alternate title
Date ( Creation )
2022-07-01
Date ( Revision )
2024-07-01
Identifier

GMRT2022_Caribbean

  Originator

  +1 (845) 359-2931 
Website
web site  

  Custodian

  +1 (845) 359-2931 
Website
web site  
Project name ( Theme )
SeaDataNet device categories ( Theme )

  • single-beam echosounders

    ,

    multi-beam echosounders

http://vocab.ndg.nerc.ac.uk/ ( Stratum )
Parameter Discovery Vocabulary (P02) ( parameter )

  • Bathymetry and Elevation

GEMET - INSPIRE themes, version 1.0 ( Theme )

  • Hydrography

SeaDataNet depth measurement reference planes ( Theme )

  • sea level

Use limitation
Access constraints
unrestricted
Use constraints
academic
Other constraints

Citation

Ryan, W.B.F., S.M. Carbotte, J.O. Coplan, S. O'Hara, A. Melkonian, R. Arko, R.A. Weissel, V. Ferrini, A. Goodwillie, F. Nitsche, J. Bonczkowski, and R. Zemsky (2009), Global Multi-Resolution Topography synthesis, Geochem. Geophys. Geosyst., 10, Q03014, doi: 10.1029/2008GC002332

Use limitation
Spatial representation type
Grid
Denominator
100000
Distance
3.75  Arc second
Metadata language
English
Character set
UTF8
Topic category
  • Oceans
N
S
E
W


Unique resource identifier
Description

Map projection parameters, values and units :

Axes units :

Unique resource identifier
Codespace

EPSG

Version

7.4

Unique resource identifier
Codespace

EPSG

Version
Number of dimensions
3
Dimension name
Column
Dimension size
11652
Dimension name
Row
Dimension size
8672
Dimension name
Time
Dimension size
1
Cell geometry
Point
Transformation parameter availability
false
Checkpoint Availability
false
Point in Pixel
  • Center
Distribution format
  • ()

    Specification

  Distributor

Distributor

No information provided.
Protocol

WWW:LINK

Name
Description
Function
Information
Hierarchy level
Dataset

Vertical extent

Minimum value
8680
Maximum value
0

Vertical CS

Vertical datum

Statement

no information

Hierarchy level
Feature
Dataset

accuracy

Gridded data positional accuracy

Name of measure

horizontal accuracy

Measure identification

horizontal accuracy of coordinate

Measure description
Evaluation method description

Quantitative result

Value type
horizontal accuracy

Quantitative attribute accuracy

Name of measure

depth

Measure identification

depth accuracy

Measure description
Evaluation method description

Quantitative result

Value
not defined

Conformance result

Date
Explanation
Hierarchy level
Software
Description
Other

software

Hierarchy level
Property type
Description

parameters of data processing

Attributes
Statement

Description of data processing in https://www.gmrt.org/about/index.php


How are swath data processed?

We use a combination of software developed in-house and open source software to process swath data for GMRT. MB-System provides the backbone of the code that we use for our data cleaning and processing. Raw multibeam sonar ping files available for each cruise are first run through a series of crude filters (e.g. ocean depth), and are then used to generate a development set of 100-m resolution tiled images and grids. These images and grids are reviewed and quantitatively interrogated using a custom version of GeoMapApp. This allows our team to assess data coverage and data quality, and to identify problems in the data that can be addressed using multibeam processing tools and techniques available through MB-System.


Data are typically processed to 100-m resolution. While our overall goal is to include only high-quality data, we sometimes include lower quality data in areas where data coverage is sparse (e.g. Southern Ocean). The data are reviewed, edited as necessary and re-gridded iteratively until the quality is suitable for inclusion in the tile set. During this process, we also determine the maximum data resolution for the cruise, the data are either gridded at 100m (default), 50m, and 25m resolution depending on sonar system capabilities and survey area. The chosen resolution is applied to the entire cruise and is therefore limited by maximum water depth. During QA/QC we also assign a quality value to the cruise on the range of 1-10 with 10 being applied to the highest quality cruises. This value is applied to the data and affects the degree of blending that happens when the data are merged into the compilation.


After extraction from the GMRT website, the grid is converted in the specified format of the EMODnet Bathymetry project before integration.

Description

Multisources bathymetry

Data sources for GMRT grid is described in https://www.gmrt.org/contributors/index.php

Hierarchy level
Dataset

Absolute external positional accuracy

Name of measure

emodnet-bathymetry.QI.Horizontal

Value
1 - Between 500m and 50m

Absolute external positional accuracy

Name of measure

emodnet-bathymetry.QI.Vertical

Value
2 - MBES low frequency (lower than 100kHz) (similar than 1+2%d)

Domain consistency

Name of measure

emodnet-bathymetry.QI.Purpose

Value
0 - Undefined

Metadata

File identifier
SDN_CPRD_1384_GMRT2022_Caribbean   XML
Metadata language
English
Character set
UTF8
Hierarchy level name

Product record

Date stamp
2024-07-05T08:29:57.372Z
Metadata standard name

ISO 19115:2003/19139 - EMODNET - BATHYMETRY

Metadata standard version

1.0

  Author

  +33(0)2 98.22.45.70 
Website
web site  
 
 

  Overviews

Capture_gmrt2022.png

Provided by

Access to the portal

Associated resources

Not available