hydro-snap 0.1.1

DEM reconditioning for hydrological applications

hydro-snap

Hydro-snap is an efficient tool for seamlessly aligning digital elevation models (DEMs) with mapped stream networks, ensuring accurate hydrological flow paths with minimal terrain alteration.

Example of a flow accumulation before (left) and after (right) alignment with HydroSnap. The DEM on the right has been aligned with the mapped stream network, ensuring accurate hydrological flow paths.

Hydro-snap allows users to:

• Align a DEM with a mapped stream network
• (Optionally) delineate a catchment from a provided outlet point
• (Optionally) force the flow accumulation to be consistent with a provided catchment boundary

The flow direction and accumulation are computed after the DEM has been aligned with the stream network, using the pysheds library.

Installation

Hydro-snap can be installed using pip:

pip install hydro-snap

Data requirements

You will need the following data to use hydro-snap:

• A digital elevation model (DEM) in GeoTIFF format
• A mapped stream network in shapefile format
• (Optional) A shapefile containing the outlet point of the catchment
• (Optional) A shapefile containing the catchment boundary
• (Optional) A shapefile containing the breaches in catchment boundary

Usage

Hydro-snap can be used to align a DEM with a mapped stream network using the following code:

from hydro_snap import recondition_dem

recondition_dem('path/to/DEM', 'path/to/streams.shp', 'output/dir')

When the catchment outlet is provided, the catchment can be delineated:

from hydro_snap import recondition_dem

# Recondition the DEM
recondition_dem('path/to/DEM', 'path/to/streams.shp', 'output/dir', 
                outlet_shp='path/to/outlet.shp')

A catchment delineation can be provided to force the flow accumulation to be consistent with its boundary. In order to allow the water to flow out of the catchment, breach(es) in the catchment boundary (outlet) must be provided:

from hydro_snap import recondition_dem

# Recondition the DEM
recondition_dem('path/to/DEM', 'path/to/streams.shp', 'output/dir', 
                catchment_shp='path/to/catchment.shp',
                breaches_shp='path/to/breaches.shp')