GEBCO Global Earth Relief

_images/igpp.png
_images/GMT_gebcosi.jpg

Usage

You access the GEBCO global relief grid by specifying the special name

@earth_gebco[_rru[_reg]]

This grid only contains observed relief and inferred relief via altimetric gravity. A second grid that gives sub-ice (si) elevations is also available and can be accessed via

@earth_geocosi[_rru[_reg]]

and is the one displayed above. The following codes for rru and the optional reg are supported (dimensions are listed for pixel-registered grids; gridline-registered grids increment dimensions by one):

GEBCO Global Earth Relief. An asterisk denotes tiled datasets.

Code

Dimensions

Reg

Size

Description

01d

360 x 180

g,p

114 KB

1 arc degree global relief (GEBCO 2021 @ 111 km)

30m

720 x 360

g,p

395 KB

30 arc minute global relief (GEBCO 2021 @ 55 km)

20m

1080 x 540

g,p

832 KB

20 arc minute global relief (GEBCO 2021 @ 37 km)

15m

1440 x 720

g,p

1.4 MB

15 arc minute global relief (GEBCO 2021 @ 28 km)

10m

2160 x 1080

g,p

3.0 MB

10 arc minute global relief (GEBCO 2021 @ 18 km)

06m

3600 x 1800

g,p

8.0 MB

6 arc minute global relief (GEBCO 2021 @ 10 km)

05m*

4320 x 2160

g,p

11 MB

5 arc minute global relief (GEBCO 2021 @ 9 km)

04m*

5400 x 2700

g,p

17 MB

4 arc minute global relief (GEBCO 2021 @ 7.5 km)

03m*

7200 x 3600

g,p

30 MB

3 arc minute global relief (GEBCO 2021 @ 5.6 km)

02m*

10800 x 5400

g,p

65 MB

2 arc minute global relief (GEBCO 2021 @ 3.7 km)

01m*

21600 x 10800

g,p

237 MB

1 arc minute global relief (GEBCO 2021 @ 1.9 km)

30s*

43200 x 21600

g,p

864 MB

30 arc second global relief (GEBCO 2021 @ 1.0 km)

15s*

86400 x 43200

p

2.9 GB

15 arc second global relief (GEBCO 2021)

03s*

432000 x 216000

g

6.8 GB

3 arc second global relief (SRTM3S)

01s*

1296000 x 432000

g

41 GB

1 arc second global relief (SRTM1S)

See GMT remote dataset usage for when resolution codes are optional or required. All of these data will, when downloaded, be placed in your ~/.gmt/server directory, with the earth_gebco files being placed in an earth/earth_gebco sub-directory, and earth_gebcosi files in an earth/earth_gebcosi sub-directory. If you do not specify a CPT then the default CPT (the GMT master geo CPT) will be used.

Technical Information

As you see, the 30s and lower resolutions are all derivatives of GEBCO’s 2021 15 arc second grids (GEBCO_Compilation_Group, 2020). We have downsampled it via Cartesian Gaussian filtering to prevent aliasing while preserving the latitude-dependent resolution in the original 15 arc sec grid. The full (6 sigma) filter-widths are indicated in parenthesis. The 3 and 1 arc second data are the SRTM 1x1 degree tiles from NASA. Note: The 3 and 1 arc second grids only extend to latitudes ±60˚ and are only available over land. When these grids are accessed as @earth_gebco_01s or @earth_gebco_03s we will automatically up-sample the relevant @earth_gebco_15s tiles to fill in the missing ocean values. If you just want the original land-only SRTM tiles you may use the special names @srtm_relief_03s or @srtm_relief_01s instead. Almost all grids are available in both gridline- and pixel-registered formats except the original pixel-registered GEBCO 2021 (here called @earth_gebco_15s) and the gridline-registered SRTM tiles.

Data References

  1. GEBCO 2021: [https://www.gebco.net/data_and_products/gridded_bathymetry_data/].

  2. SRTMGL3 tiles: [https://lpdaac.usgs.gov/products/srtmgl3v003].

  3. SRTMGL1 tiles: [https://lpdaac.usgs.gov/products/srtmgl1v003].