GTOPO30 is a digital elevation model for the world, developed by United States Geological Survey (USGS). It has a 30-arc second resolution (approximately 1 km),  and is split into 33 tiles stored in the USGS DEM file format.
This map is derived from GTOPO30 data that describes the elevation of Earth's terrain at intervals of 30 arcseconds (approximately 1 km). It uses hypsometric tints instead of contour lines to indicate elevation.
|Each tile is available at a resolution of 1800 × 1800 pixels (approximate file size 1 MB, 60 pixels = 1 degree, 1 pixel = 1 minute)|
- USGS EROS Archive - Digital Elevation - Global 30 Arc-Second Elevation (GTOPO30)
- "Accuracy". Retrieved July 26, 2017.
- GTOPO30 Page.