pgh_raster

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:

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_raster CASCADE;  -- requires: plpgsql, postgis, postgis_raster, pghydro

Usage

Sources: PGHydro README, pgh_raster SQL

pgh_raster adds raster-based hydrological products to PgHydro. It stores DEM, flow-path, flow-direction, and flow-accumulation rasters, then exposes functions for upstream/downstream pixel tracing, drainage-area analysis, elevation lookup, elevation profiles, and raster clipping.

Enable

CREATE EXTENSION postgis;
CREATE EXTENSION postgis_raster;
CREATE EXTENSION pghydro;
CREATE EXTENSION pgh_raster;

Raster Tables

The extension creates the pgh_raster schema with tables such as:

Load raster products with PostGIS Raster tooling such as raster2pgsql, using the SRID and tiling scheme that matches the drainage dataset.

Analysis Functions

Function groups include downstream and upstream pixel traversal, upstream area lookup, downstream drainage point and area lookup, elevation pixel values, elevation profiles, and raster clipping.

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

Notes

pgh_raster depends on both pghydro and postgis_raster. Keep raster alignment, SRID, and nodata handling consistent with the vector drainage layers before deriving hydrogeomorphological metrics.