![]() ![]() Venus was mapped by radar altimetry where the footprint of the radar is ~10 km so the map is provided on about a 10 km grid but the ½ wavelength resolution is only about 20 km. Mercury, Mars, and the Moon all have topographic maps that have much better than 1 km spatial resolution. The other 89% is mapped by satellite altimetry at a ½ wavelength resolution of 6 km. For the latest bathymetry, “11% of the oceans is mapped by ships at 500 m or better resolution. So it is very safe to say that our maps of most of the ocean floor don’t even come close to the resolution of maps we have of for the whole of the surfaces of Mars and the Moon.”ĭavid Sandwell brought to our attention that Mercury has also been mapped at a resolution of 665 m, ten times better than the seabed. That is the worst-case scenario but still applies to big chunks of the ocean. The satellite altimetry data used by Smith and Sandwell (1997) to fill in the holes where actual soundings are missing provides +/- 100 m vertical estimates at 12.5 km spacing. A resolution of 1 km is 100 times lower resolution than the 100 m DTM of the moon and 400 times worse than Mars!īut we don’t really have a 1 km map for the ocean because even though the grid is 1 km, the underlying data are spaced much further apart in most places. The resolution of the SRTM 30 arc second ( Shuttle Radar Topography Mission) DTM for the ocean is supposedly 1 km (Becker et al., 2009). ![]() “For the ocean floor we can’t even get close to the resolution of these models. stereo images from the one-year nominal mission and the first months of the science mission phase are combined to produce a near-global digital terrain model (DTM) with a pixel spacing of 100 m, the Global Lunar DTM 100 m, or GLD100. Its website states “ Wide-angle Camera (WAC) …. ![]() You can download a 100 m Digital Terrain Model for the Moon. The DTM elevation data derived from these images is provided in pixels of up to 50 m, with a height accuracy of 10 m.” The website states “ The high-resolution images used have a resolution of 10 m/pixel. You can download from the web a 50 m Digital Terrain Model (DTM) of the surface of Mars. I thank Peter Harris and David Sandwell for providing links to the evidence that shows indeed maps of other planets (and at least one asteroid) are at a finer spatial resolution and with better coverage than our oceans. However, I had not noticed papers that provided evidence for this or cited primary sources. I have often read and heard it stated that the seabed is less well mapped than the surface of other planets. ![]()
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