Lava Field versus Lava Flow?

I’m wondering if the distinction between a “lava field” versus a “lava flow” is important to maintain in OSM. The two concepts are mentioned in Proposal:Volcanic features - OpenStreetMap Wiki

I’m asking because a recent sequence of 28 changesets have completely removed the geological=volcanic_lava_flow tag from OSM and replaced it with geological=volcanic_lava_field.

I don’t know that these changes have been discussed, but if so, I’d be interested to follow the discussion.

What do other mappers think, especially those with some background in geology?

Maybe he simple changes flows (possible lines) to fields (ways / areas)?

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For me a lava flow is hot fluid material making its way down from a crater/fissure.
This is a feature typically only present for some days or months before the lava solidifies to a lava field.

Because of the temporary nature I would not map lava flows neither as line nor as area.
At least after some months the tagging gets wrong and shold turn to volcanic_lava_field.

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It looks like this is a “campaign” by one mapper. Many people have commented about their edits (including you - thanks for that) and many people have not received replies.

Unless anyone speaks up in favour of this edits I’d suggest that they are reverted, given the number of people have commented about problems with them. If @Krako73 would like to make a case for keeping these edits in OSM, then this thread would be an excellent place to do that.

– Andy (from the DWG)


I suppose you can review the changesets and come to your own conclusions, but I’m really asking about whether it is important to preserve these two different tag values.

This was my initial impression as well. However, I have noticed that geological literature describes lava fields as being composed of sequential lava flows that occurred at different times. And I noticed that some mappers have been careful enough to preserve this information in OSM by mapping each lava flow individually.


Ok, that’s a more precise clarification that lava flow means solidified flow. But then the tagging of the occurence becomes important since lava flows often supersede former solidified flows.


It looks like the consensus here is that keeping both volcanic_lava_flow and volcanic_lava_field tags is valuable. Based on that, I may revert the recent tag changes to restore the volcanic_lava_flow tags in OSM.

If anyone is opposed to restoring these tags, please let me know within the next day or so.

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I don’t oppose a revert, but it should be accompanied by an explanation of volcanic_lava_flow based on our discussion at least in the changeset, even better by an entry in the wiki table for geological to avoid/reduce further misinterpretation.

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That’s a good idea.

Both tags were originally proposed in Proposal:Volcanic features - OpenStreetMap Wiki and the geological=volcanic_lava_field tag was documented separately. The geological=volcanic_lava_flow tag did not have its own Wiki page but I have added one based on this discussion.

I would welcome comments and revisions on the new geological=volcanic_lava_flow page!

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