Bearbeiten von „Tulsa Massacre“

''The buildings, maps and data presented in this article are based on historical records. In as many cases as possible, multiple sources were used to confirm details like the location of businesses and residences. When there were differing accounts or information, The Times used what was cited by the most sources. The number of killings in the massacre has been estimated to be up to 300, but a precise number was not available. Street addresses of some buildings were numbered in different ways, depending on the source.''

''The 3-D model of Tulsa, Okla., was created using a series of both computerized and manual steps that transformed historical material into digital data. First, we took images of Sanborn insurance maps from 1920 and 1915 and used a process called georeferencing to align them to modern geography. The 1920 maps came from the Tulsa Historical Society and Museum and were used to reconstruct as much of Greenwood and downtown Tulsa as possible. The 1915 maps were from the Library of Congress and were used to fill in other parts of Tulsa, where 1920 maps were not available.''

Die Karten von 1915 sind diese: 
https://www.loc.gov/item/sanborn07276_009/
Daraus:
* https://www.loc.gov/resource/g4024tm.g4024tm_g072761915/?sp=10&st=image
* https://www.loc.gov/resource/g4024tm.g4024tm_g072761915/?sp=11&st=image
* https://www.loc.gov/resource/g4024tm.g4024tm_g072761915/?sp=24&st=image

''Next, we wrote a computer program to extract the building outlines from those maps using a technique called machine learning. We also created an application to input the height information for each building from the Sanborn maps.''

''Archival photographs and maps were used to create a detailed model of the 100 block of Greenwood Avenue. Buildings or parts of buildings without photographic reference are shown without details. The street grid was created by georeferencing a 1921 street map of Tulsa from the Library of Congress.''

''We utilized a combination of optical character recognition and manual data entry to digitize the Polk-Hoffhine Tulsa City Directory from 1921, obtained from the Tulsa City-County Library. Those data were used to analyze and map businesses in Greenwood. Additional businesses were identified using the “Tulsa Colored Business Directory” in The Tulsa Star (1913-21) and The List of Losses published in “Events of The Tulsa Disaster” by Mary E. Jones Parrish. Owners of businesses on the 100 block were identified using The Tulsa Star and accounts of survivors and their descendants.''

''To create the maps of the occupations of African-American residents in Greenwood, we analyzed 1920 U.S. census data from Ancestry.com for residents for which occupation data was recorded. Our analysis included residents who the 1920 census classified as Black or mulatto. We then mapped the homes of thousands of those residents using the 1920 Sanborn maps.''

''Street maps from 1921 and Sanborn maps from 1939 were also used to help map addresses. The addresses of landmarks and other buildings were used to help determine the order of house numbers on a block. In some cases, Open Street Maps was used to locate addresses where the numbering system had not changed. Street name changes from the 1920 and 1921 city directories were incorporated in this process.''

''We categorized occupations into three broad categories: professionals, skilled craftspeople and service workers. Records in which occupations were illegible, or were without a house number or clear address were excluded.''

''While the Greenwood neighborhood boundary is not officially defined, the outline shown in this piece includes the predominantly African-American area shown in the 2001 state commission report as well as some additional areas, based on our analysis of census data.''