NASA Global Earth Day/Night Images

_images/nasa-logo-web-rgb.png
_images/GMT_daynight.jpg

We serve two NASA image products: The Blue and Black marble mosaics. We have filtered and down-ampled those as well at the same resolutions that are available for the Earth DEMs. However, all images are pixel-registered only. These images may be plotted with grdimage or grdview and manipulated by grdmix. The above example mixes both images according to a day-night mask and adds illumination from a corresponding Earth DEM.

Usage

You access a global daytime image by specifying the special names

@earth_day[_rru]

Similarly for the nighttime view:

@earth_night[_rru]

The following codes for rru are supported:

NASA Global Earth Day/Night Images.

Code

Dimensions

Size

Description

01d

360 x 180

128 KB

1 arc degree image view (Blue|Black Marble mosaic @ 111 km)

30m

720 x 360

435 KB

30 arc minute image view (Blue|Black Marble mosaic @ 55 km)

20m

1080 x 540

918 KB

20 arc minute image view (Blue|Black Marble mosaic @ 37 km)

15m

1440 x 720

1.6 MB

15 arc minute image view (Blue|Black Marble mosaic @ 28 km)

10m

2160 x 1080

3.4 MB

10 arc minute image view (Blue|Black Marble mosaic @ 18 km)

06m

3600 x 1800

8.8 MB

6 arc minute image view (Blue|Black Marble mosaic @ 10 km)

05m

4320 x 2160

13 MB

5 arc minute image view (Blue|Black Marble mosaic @ 9 km)

04m

5400 x 2700

19 MB

4 arc minute image view (Blue|Black Marble mosaic @ 7.5 km)

03m

7200 x 3600

33 MB

3 arc minute image view (Blue|Black Marble mosaic @ 5.6 km)

02m

10800 x 5400

71 MB

2 arc minute image view (Blue|Black Marble mosaic @ 3.7 km)

01m

21600 x 10800

258 MB

1 arc minute image view (Blue|Black Marble mosaic @ 1.9 km)

30s

43200 x 21600

935 MB

30 arc second image view (Blue|Black Marble mosaic original)

See GMT remote dataset usage for when resolution codes are optional or required. All of these images will, when downloaded, be placed in your ~/.gmt/server director under the earth/earth_day and earth/earth_night sub-directories.

Technical Information

The 01m and lower resolution images are derivatives of NASA’s Blue and Black marble image mosaics. We have downsampled them via Cartesian Gaussian filtering to prevent aliasing while preserving the latitude-dependent resolution in the original images. The full (6 sigma) filter-widths are indicated in parenthesis. The dimensions above reflect the number of nodes covered by the global images and the sizes refer to the geotiff files on the remote server. Note: This data set is experimental and the format and delivery is likely to change in the future (e.g., via image tiles). To make the files as small as possible we have also downgraded them from 24-bit to 8-bit indexed images.

Data References

  1. Blue Marble: [https://visibleearth.nasa.gov/images/57752/blue-marble-land-surface-shallow-water-and-shaded-topography].

  2. Black Marble: [https://earthobservatory.nasa.gov/features/NightLights/page3.php].