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fix: avoid division by zero for flat faces on PostgreSQL 18 #212

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Merged
jravani merged 3 commits into from
Oct 22, 2026
Merged

fix: avoid division by zero for flat faces on PostgreSQL 18 #212

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b2f3788
fix: avoid division by zero for flat faces on PostgreSQL 18
jravani Oct 21, 2026
b82923d
docs: changelog entry for the PostgreSQL 18 extraction fix
jravani Oct 22, 2026
d4069ce
Merge remote-tracking branch 'origin/main' into fix/surface-dimension…
jravani Oct 22, 2026
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5 changes: 5 additions & 0 deletions CHANGELOG.md
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Expand Up @@ -23,6 +23,11 @@ Fixes:
against every cell: for Deggendorf and Koeln in one database that
took 29 minutes before linking began. Each building's cell is now
computed from its coordinates; the batches are unchanged.
- Feature extraction works on PostgreSQL 18. There every batch holding
a flat roof or ground surface failed with division by zero in
surface_dimensions, so no building was extracted. PostgreSQL 16 and
17 were not affected. A database created by an earlier release gets
the fixed function on its next -reset-city2tabula.

## v0.11.4 (2026-10-20)

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4 changes: 3 additions & 1 deletion sql/functions/01_surface_area_corrected_geom.sql
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Expand Up @@ -78,7 +78,9 @@ CREATE FUNCTION {city2tabula_schema}.surface_dimensions(
WITH axes AS (
SELECT -ny / h AS ux, nx / h AS uy,
-nz * nx / h AS vx, -nz * ny / h AS vy, h AS vz
FROM (SELECT sqrt(nx * nx + ny * ny) AS h) s
-- NULLIF because PostgreSQL 18 computes the axes of a flat face (h = 0)
-- before the WHERE below discards it, and raises division by zero.
FROM (SELECT NULLIF(sqrt(nx * nx + ny * ny), 0) AS h) s
WHERE ABS(nz) <= 0.985
),
projected AS (
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