+
+
+@_migration(4, 0, 99, 2)
+def add_step_column_for_interpolation(conn, **_):
+ """ Add a new column 'step' to the interpolations table.
+
+ Also convers the data into the stricter format which requires that
+ startnumbers comply with the odd/even requirements.
+ """
+ with conn.cursor() as cur:
+ # Mark invalid all interpolations with no intermediate numbers.
+ cur.execute("""UPDATE location_property_osmline SET startnumber = null
+ WHERE endnumber - startnumber <= 1 """)
+ # Align the start numbers where odd/even does not match.
+ cur.execute("""UPDATE location_property_osmline
+ SET startnumber = startnumber + 1,
+ linegeo = ST_LineSubString(linegeo,
+ 1.0 / (endnumber - startnumber)::float,
+ 1)
+ WHERE (interpolationtype = 'odd' and startnumber % 2 = 0)
+ or (interpolationtype = 'even' and startnumber % 2 = 1)
+ """)
+ # Mark invalid odd/even interpolations with no intermediate numbers.
+ cur.execute("""UPDATE location_property_osmline SET startnumber = null
+ WHERE interpolationtype in ('odd', 'even')
+ and endnumber - startnumber = 2""")
+ # Finally add the new column and populate it.
+ cur.execute("ALTER TABLE location_property_osmline ADD COLUMN step SMALLINT")
+ cur.execute("""UPDATE location_property_osmline
+ SET step = CASE WHEN interpolationtype = 'all'
+ THEN 1 ELSE 2 END
+ """)
+
+
+@_migration(4, 0, 99, 3)
+def add_step_column_for_tiger(conn, **_):
+ """ Add a new column 'step' to the tiger data table.
+ """
+ with conn.cursor() as cur:
+ cur.execute("ALTER TABLE location_property_tiger ADD COLUMN step SMALLINT")
+ cur.execute("""UPDATE location_property_tiger
+ SET step = CASE WHEN interpolationtype = 'all'
+ THEN 1 ELSE 2 END
+ """)