What are these lines on satellite imagery of earth’s oceans?



Someone explained to me that these may be areas where higher resolution sonar imaging is available as opposed to the surrounding areas of which would be low resolution.

Could someone explain in more detail/lay man’s terms?
Also, if the above explanation is along the right lines (pun unintended) are such images readily available to the public?

In: 261

From what a brief search turned up, that’s likely from [echosoundIng](https://en.m.wikipedia.org/wiki/Echo_sounding). It’s where ships measure the depth of the ocean using acoustic waves.

What you see on Google Maps is not always satellite images. If you zoom in on land, you mainly the images taken by aircraft, and only if you zoom out far enough do you get satellite images — for land and freshwater lakes.

For the seas and oceans, it’s not images at all, but a 3D rendering showing how deep the sea is.

To do so, they use depth measurements taken with echo sounding: a ship sends a sound wave down and measures how long it takes to hear the echo coming back from the ground.

Google seems to mainly use data from surveys mapping out the depth along a rather loosely spaced grid of points of the ocean, as such data has been used for making nautical maps since long.

Along the lines you see, they have finer data: obviously a ship was going slowly along the line and mapping the depth directly below and a bit to the sides with much higher precision than usual.

Most of the ocean floor is mapped by measuring gravity with satellites. The lines are where a ship turned on the sonar while going somewhere else.