pgh_consistency

Overview

Version

Build

You can build the RPM / DEB packages for pghydro using pig build:

pig build pkg pghydro         # build RPM / DEB packages

Install

You can install pghydro directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:

pig repo add pgsql -u          # Add repo and update cache

Install the extension using pig or apt/yum/dnf:

• Install
• pig
• dnf
• apt

pig install pghydro;          # Install for current active PG version

pig ext install -y pghydro -v 18  # PG 18
pig ext install -y pghydro -v 17  # PG 17
pig ext install -y pghydro -v 16  # PG 16
pig ext install -y pghydro -v 15  # PG 15
pig ext install -y pghydro -v 14  # PG 14

dnf install -y pghydro_18       # PG 18
dnf install -y pghydro_17       # PG 17
dnf install -y pghydro_16       # PG 16
dnf install -y pghydro_15       # PG 15
dnf install -y pghydro_14       # PG 14

apt install -y postgresql-18-pghydro   # PG 18
apt install -y postgresql-17-pghydro   # PG 17
apt install -y postgresql-16-pghydro   # PG 16
apt install -y postgresql-15-pghydro   # PG 15
apt install -y postgresql-14-pghydro   # PG 14

Create Extension:

CREATE EXTENSION pgh_consistency CASCADE;  -- requires: plpgsql, postgis, pghydro

Usage

Sources: PGHydro README, pgh_consistency SQL

pgh_consistency is a PgHydro companion extension for checking and cleaning hydrographic network data. It creates the pgh_consistency schema with quality-control tables and functions for drainage-line and drainage-area geometry, topology, and Pfafstetter consistency checks.

Enable

Install it after PostGIS and the core pghydro extension:

CREATE EXTENSION postgis;
CREATE EXTENSION pghydro;
CREATE EXTENSION pgh_consistency;

Inspect Check Tables

The extension stores findings in tables named after the issue being detected:

SELECT tablename
FROM pg_tables
WHERE schemaname = 'pgh_consistency'
ORDER BY tablename;

Examples include pghft_drainagelineisdisconnected, pghft_drainagelineisnotvalid, pghft_drainageareaisnotvalid, pghft_drainageareaoverlapdrainagearea, pghft_pointvalencevalue2, and pghft_pointdivergent.

Main Workflows

Use the functions in pgh_consistency to prepare and validate the drainage network before running analytical PgHydro routines. The SQL objects include helpers to split drainage lines at multipoints, snap drainage lines to a grid, remove repeated points, create drainage-line vertex intersections, break drainage lines, and detect invalid, non-simple, disconnected, overlapping, looping, or misclassified drainage features.

SELECT nspname, proname
FROM pg_proc p
JOIN pg_namespace n ON n.oid = p.pronamespace
WHERE nspname = 'pgh_consistency'
ORDER BY proname;

Notes

The extension assumes PgHydro’s base drainage tables are already populated. Run consistency checks before exporting or calculating higher-level hydrological products so invalid geometries and broken network links are visible early.