Topographic Exposure Index for Quebec at 50-Meter Resolution

Quebec's TOPEX dataset provides a raster index of topographic exposure to wind, calculated from NASA SRTM terrain data. The matrix file has a spatial resolution of 50 meters and covers the territory south of 52°40' and west of 61°10'. It was created by the Government of Quebec for windthrow hazard assessment.

Use Cases

• Incorporate the TOPEX raster values as an input layer in a GIS-based windfall vulnerability assessment system.
• Analyze the relationship between TOPEX index values and local topography derived from the SRTM Digital Terrain Model.
• Model wind exposure patterns across Quebec's landscape using the 50-meter resolution raster data.
• Combine TOPEX data with other factors for a complete windthrow risk analysis, noting its exclusion of wind channeling effects.

Strengths

• Derived from the authoritative NASA Shuttle Radar Topography Mission (SRTM) Digital Terrain Model.
• Provides consistent 50-meter spatial resolution across the covered region.
• Covers the entire territory of Quebec south of 52°40' and west of 61°10', extending 75 to 125 meters beyond borders for full coverage.

Limitations

• The TOPEX index does not account for the wind channeling effect, which can influence windfall in certain locations.
• As a static raster, it may not reflect recent topographic changes from events like landslides or construction.

Provenance

Source

Government and Municipalities of Québec

Collection Method

Calculated from a mosaic of NASA SRTM tiles, projected into NAD 1983 Quebec Lambert and resampled to 50-meter resolution.

Time Range

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Freshness

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Geography

Quebec, Canada, specifically the territory south of approximately 52°40' and west of 61°10'.