This is more like the construction date of buildings that have survived. Some early neighborhoods (like palms) have been completely replaced building by building so they really appear as dark here when they weren't. It had a downtown in the 1890s but all those buildings are gone. https://en.wikipedia.org/wiki/Palms,_Los_Angeles#/media/File...

it's basically this data: https://portal.assessor.lacounty.gov/ through this portal https://data.lacity.org/