Adding HOLC indicator (#1579)

Added HOLC indicator (Historic Redlining Score) from NCRC work; included 3.25 cutoff and low income as part of the housing burden category.
This commit is contained in:
Emma Nechamkin 2022-05-12 12:07:08 -04:00 committed by Emma Nechamkin
commit 1782d022a9
10 changed files with 202 additions and 40 deletions

View file

@ -47,16 +47,21 @@ class MappingInequalityETL(ExtractTransformLoad):
self.HOLC_GRADE_AND_ID_FIELD: str = "holc_id"
self.CITY_INPUT_FIELD: str = "city"
self.HOLC_GRADE_D_FIELD: str = "HOLC Grade D"
self.HOLC_GRADE_D_FIELD: str = "HOLC Grade D (hazardous)"
self.HOLC_GRADE_C_FIELD: str = "HOLC Grade C (declining)"
self.HOLC_GRADE_MANUAL_FIELD: str = "HOLC Grade (manually mapped)"
self.HOLC_GRADE_DERIVED_FIELD: str = "HOLC Grade (derived)"
self.COLUMNS_TO_KEEP = [
self.GEOID_TRACT_FIELD_NAME,
field_names.HOLC_GRADE_C_TRACT_PERCENT_FIELD,
field_names.HOLC_GRADE_C_OR_D_TRACT_PERCENT_FIELD,
field_names.HOLC_GRADE_C_OR_D_TRACT_50_PERCENT_FIELD,
field_names.HOLC_GRADE_D_TRACT_PERCENT_FIELD,
field_names.HOLC_GRADE_D_TRACT_20_PERCENT_FIELD,
field_names.HOLC_GRADE_D_TRACT_50_PERCENT_FIELD,
field_names.HOLC_GRADE_D_TRACT_75_PERCENT_FIELD,
field_names.REDLINED_SHARE,
]
self.df: pd.DataFrame
@ -113,34 +118,58 @@ class MappingInequalityETL(ExtractTransformLoad):
how="left",
)
# Create a single field that combines the 'derived' grade D field with the
# manually mapped grade D field into a single grade D field.
merged_df[self.HOLC_GRADE_D_FIELD] = np.where(
(merged_df[self.HOLC_GRADE_DERIVED_FIELD] == "D")
| (merged_df[self.HOLC_GRADE_MANUAL_FIELD] == "D"),
True,
None,
)
# Create a single field that combines the 'derived' grade C and D fields with the
# manually mapped grade C and D field into a single grade C and D field.
## Note: there are no manually derived C tracts at the moment
# Start grouping by, to sum all of the grade D parts of each tract.
grouped_df = (
merged_df.groupby(
by=[
self.GEOID_TRACT_FIELD_NAME,
self.HOLC_GRADE_D_FIELD,
],
# Keep the nulls, so we know the non-D proportion.
dropna=False,
)[self.TRACT_PROPORTION_FIELD]
for grade, field_name in [
("C", self.HOLC_GRADE_C_FIELD),
("D", self.HOLC_GRADE_D_FIELD),
]:
merged_df[field_name] = np.where(
(merged_df[self.HOLC_GRADE_DERIVED_FIELD] == grade)
| (merged_df[self.HOLC_GRADE_MANUAL_FIELD] == grade),
True,
None,
)
redlined_dataframes_list = [
merged_df[merged_df[field].fillna(False)]
.groupby(self.GEOID_TRACT_FIELD_NAME)[self.TRACT_PROPORTION_FIELD]
.sum()
.rename(new_name)
for field, new_name in [
(
self.HOLC_GRADE_D_FIELD,
field_names.HOLC_GRADE_D_TRACT_PERCENT_FIELD,
),
(
self.HOLC_GRADE_C_FIELD,
field_names.HOLC_GRADE_C_TRACT_PERCENT_FIELD,
),
]
]
# Group by tract ID to get tract proportions of just C or just D
# This produces a single row per tract
grouped_df = (
pd.concat(
redlined_dataframes_list,
axis=1,
)
.fillna(0)
.reset_index()
)
# Create a field that is only the percent that is grade D.
grouped_df[field_names.HOLC_GRADE_D_TRACT_PERCENT_FIELD] = np.where(
grouped_df[self.HOLC_GRADE_D_FIELD],
grouped_df[self.TRACT_PROPORTION_FIELD],
0,
grouped_df[
field_names.HOLC_GRADE_C_OR_D_TRACT_PERCENT_FIELD
] = grouped_df[
[
field_names.HOLC_GRADE_C_TRACT_PERCENT_FIELD,
field_names.HOLC_GRADE_D_TRACT_PERCENT_FIELD,
]
].sum(
axis=1
)
# Calculate some specific threshold cutoffs, for convenience.
@ -154,15 +183,14 @@ class MappingInequalityETL(ExtractTransformLoad):
grouped_df[field_names.HOLC_GRADE_D_TRACT_PERCENT_FIELD] > 0.75
)
# Drop the non-True values of `self.HOLC_GRADE_D_FIELD` -- we only
# want one row per tract for future joins.
# Note this means not all tracts will be in this data.
# Note: this singleton comparison warning may be a pylint bug:
# https://stackoverflow.com/questions/51657715/pylint-pandas-comparison-to-true-should-be-just-expr-or-expr-is-true-sin#comment90876517_51657715
# pylint: disable=singleton-comparison
grouped_df = grouped_df[
grouped_df[self.HOLC_GRADE_D_FIELD] == True # noqa: E712
]
grouped_df[field_names.HOLC_GRADE_C_OR_D_TRACT_50_PERCENT_FIELD] = (
grouped_df[field_names.HOLC_GRADE_C_OR_D_TRACT_PERCENT_FIELD] > 0.5
)
# Create the indicator we will use
grouped_df[field_names.REDLINED_SHARE] = (
grouped_df[field_names.HOLC_GRADE_C_OR_D_TRACT_PERCENT_FIELD] > 0.5
) & (grouped_df[field_names.HOLC_GRADE_D_TRACT_PERCENT_FIELD] > 0)
# Sort for convenience.
grouped_df.sort_values(by=self.GEOID_TRACT_FIELD_NAME, inplace=True)