ORMGP Topological Watercourses

Description

The Ontario Hydro Network (OHN) - Watercourse layer offered by the Ontario Ministry of Natural Resources and Forestry has been analyzed based on a spatial analysis to define a connectivity network and a directional graph. Watercourse channel segments are topologically correct, meaning that every segments is defined by its upstream and downstream segments.

• Type
  • Vector - Polyline shapefile.
• Geographic Extent
  • The extended ORMGP Study Area covering the Niagara peninsula to the Bay of Quinty.
• Maintenance Standard
  • Periodically updated in coordination with OHN updates.

Georeferencing and Accuracy

• Horizontal Datum
  • North American Datum 1983
• Ellipsoid
  • GRS 1980
• Prime meridian
  • Greenwich
• Projection
  • Ontario MNR Lambert (EPSG 3161)
• Horizontal Accuracy
  • 1.5m
• Unit
  • metre
• Information source
  • Ontario Ministry of Natural Resources via Conservation Ontario.

Data Sources and Restrictions

• Use Constraint
  • None - in accordance with ORMGP disclaimer
• Citation
  • Oak Ridges Moraine Ground Water Program (2023) Sub-Watersheds.
• Agency Originator
  • Oak Ridges Moraine Groundwater Program (ORMGP)
• Agency Distributor
  • Oak Ridges Moraine Groundwater Program (ORMGP)

Methodology

• Data Source - Ontario Hydro Network (OHN) - Watercourse
  • See Source metadata
• Vector Processing

  • OHN watercourse layer is reprojected to EPGS 3161

  • Watercourses are “segmentized”: polylines are defined as single linear features from junction to junction.

  • Certain stream segments were manually removed in order to prevent “unnatural” flow connectivity. (This commonly occurs along man-made canal routes such as the Trent-Severn waterway.)

  • An adjacency matrix is built to collect segment endpoints that are close to one another. Adjacency is assumed to imply segment connectivity.

  • topological ordering is then performed, attributing segments with their appropriate Strahler (1952) code.

• Replaces or Updates
  • Oak Ridges Moraine Groundwater Program (v2020) sub-watershed layer.
• References
  • Strahler, A.N., 1952. Hypsometric (area-altitude) analysis of erosional topology, Geological Society of America Bulletin 63(11): 1117–1142.
• Contact
  • email (support@owrc.ca)

Last Modified: 2024-03-24