Is the “is_in” field from Overpass API coming directly from the OSM database?
I’m wondering why it’s populated only for very few cities… it seems that it would be easy enough to populate it from the areas the city is in?.. Otherwise, what would be the point of this field? About 59,000 place=city|town don’t have it populated and 29,000 do.
Example of a node that has it specified:
It’s only necessary if the containment relationships are not obvious. Wiltshire is mapped as an area, so there is no need to use is_in.
The example you gave is incorrectly punctuated. The punctuation should be semicolons, not commas. That is the general rule for multiple values.
That makes sense. I think in most cases when it’s populated it’s obvious, but I understand what this field is for now.