IEDA: Marine Geoscience Data System

GMRT GridServer Web Service


The GridServer service provides access to gridded data from the Global Multi-resolution Topography (GMRT) Synthesis. Requested data may be up to 2GB, or approximately 20 by 20 degrees at 100 meters per node (maximum available resolution). A variety of output formats are supported.

  • Data Formats
    • GMT v3 Compatible NetCDF (GMT id=cf)
    • COARDS/CF1.6 Compliant NetCDF (GMT id=nd)
    • GeoTIFF
  • Metadata Formats
    • XML (metadata)
    • JSON (metadata)
    • Plain text (metadata)


Data Request Base URL


Metadata Request Base URL


Query Parameters

name example description
(OR: south)
-10.0 The southernmost latitude.
(OR: north)
10.0 The northernmost latitude.
(OR: west)
-10.0 The westernmost longitude.
(OR: east)
10.0 The easternmost longitude.
format netcdf The output file format for data requests. Metadata requests will return information about the specified file format.
(valid formats: netcdf, coards, esriascii, geotiff)
resolution default Resolution keyword.
(valid keywords: default, med, high, max)
mresolution 200 The grid resolution in meters/node. Max resolution ≈ 100m at the equator. If specified resolution is above file size limit, GridServer will get the resolution closest to the file size limit.

Notes about Resolution

The "resolution" query parameter can be used to quickly retrieve a grid. The "default" keyword returns the largest grid resolution of less than 1000 nodes in width or height. The "med" keyword is double this resolution, and likewise the "high" keword is 4x this resolution. The "max" keyword returns the resolution closest to 100 m/node without going over the 2GB file limit. If "mresolution" is specified, the "resolution" parameter is ignored.

layer topo The data layer to retrieve
topo: The unmasked grid. Unmasked grids are filled with GEBCO_2014 where high-resolution data do not exist in the ocean.
topo-mask: The masked grid. Masked grids contain only high-resolution data (≈100 m) in the ocean, NaNs elsewhere.
metadata: An alternative means to request metadata for a region.
mformat xml The output format for metadata requests.
(valid formats: xml, json, text)
See Description tab for more information about service.