[Tagging] Large fire perimeter tagging?
steveaOSM at softworkers.com
Thu Sep 24 22:07:05 UTC 2020
On Sep 24, 2020, at 2:53 PM, Joseph Eisenberg <joseph.eisenberg at gmail.com> wrote:
> Most large wildfires do not burn the canopy (the tallest trees) in forests with trees over 10 meters in height.
Noted, thank you.
> The perimeter of the wildfire, shown commonly on public maps, does not determine which areas have been burned. Often there are large areas of vegetation along canyon bottoms and streambeds which are unburned, within the perimeter.
Something I already DID know, also noted, thank you.
> You will need new aerial imagery or detailed on-the-ground survey to determine the surviving areas of vegetation.
Something I have anticipated (apparently correctly), yet which isn't available now (though I assume will be, in the regular course of imagery being updated), so also noted, thank you.
> I would not recommend attempting to map the current official perimeter of the fire, since this changes on a daily or hourly basis: it is a temporary event which is not really verifiable from the standpoint of an OpenStreetMap volunteer mapper.
It isn't anticipated, it was completed about a month ago, containing only two versions, creation with start_date and one a couple days ago to add the end_date tag. It is a lightweight data structure: one polygon with three tags. I don't intend to delete it, as it marks a distinct boundary in the real world regarding real world components (like landuse and land cover) that OSM already maps — indeed which OSM already 100% maps in the area noted —yet these (existing landuse and land cover) polygons may have their nature / character quite substantially altered from the fire.
The event WAS temporary (and determinable from start_date and end_date keys), the aftermath will indisputably last years, perhaps decades. OSM will be mapping in the area during the meantime.
> Database users who need these perimeters should download the latest version from the official sources.
Yes, AND OSM users who map in areas affected by the fire want (likely need) fire perimeter data to delineate where substantial "re-mapping" almost certainly must take place.
Thank you for your quick reply!
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