What three new USGS maps reveal about Mars

Re:What three new USGS maps reveal about Mars by defrost on Saturday January 14, 2023 @01:26AM (#34377816)

Have you ever read those irritating comments on HN where they assume all manner of domain knowledge like bits, bytes, containers, .. etc?

Who'd have thought articles from the United States Geological Survey would expect some modicum of knowledge about geology?

Anyhow, here we go - rivers cut courses through soft substances, light sands, etc ..

Rivers carry heavy sediments from eroding hard objects upstream, clays, metals, granites, etc.

Rivers dry up and leave a heavy hardening layer at the bottom of their former course.

Light sands dry up and blow away .. leaving the former course of the river as a higher ridge of harder material different to the surrounding layers.

There are, of course, many other geologic processes that can result in similar features, many of these are covered in introductory geology books and classes.

WRT Maps:

The linked maps have image and metadata components, and full wall display integrated map sheets with legends.

eg Scientific Investigations Map 3470 (aka Sim3470), Geologic Map of Olympus Mons Caldera, Mars [1]

has quite a detailed breakdown of the colours and their meanings.

[1] https://pubs.usgs.gov/sim/3470/sim3470_sheet.pdf

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Re:What three new USGS maps reveal about Mars by JumpCrisscross on Saturday January 14, 2023 @01:54AM (#34377924)

Thank you. More broadly, when a credible source irritates with conciseness, that's a font for exploration, not complaining the wine wasn't chilled appropriately.

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Re:What three new USGS maps reveal about Mars by Dalewyn on Saturday January 14, 2023 @04:02AM (#34378615)

I think the question to be asking is who the intended audience for this article is.

It's worded in a way that seems to be for the layman, but the map snippets featured in the article convey no useful information because of the aforementioned lack of legends.

The arcgis maps linked to in the article, on the other hand, have a full legend and are fully interactable. Plenty useful for both laymen and experts alike.

I think the article could be presented better so there's less dissonance in its intention.

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Re:What three new USGS maps reveal about Mars by moloch-hai on Saturday January 14, 2023 @05:25PM (#34384741)

It would have sufficed to put the legend in as one of the in-line images.

When looking with my phone, the big PDF does not display.

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