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Canopy Height Model Filter
Overview
The Canopy Height Model Filter allows you to dynamically filter and visualize forest canopy height data. This tool enables you to focus on specific height ranges and analyze forest structure across different elevation bands.
What is the Canopy Height Model?
The Canopy Height Model layer shows forest canopy heights in meters across the landscape. Each area contains a height value representing the canopy elevation at that location.
Data Information
- Source: Visual Tas
- Resolution: 50cm × 50cm per pixel (high-resolution detail)
- Coverage Area: PTPZ Land with 100m buffer zone
- Units: Meters above ground level
- Range: 0-100+ meters
- Display: Color gradient from low (green) to high (brown/red) heights
How the Filter Works
The Canopy Height Model Filter allows you to:
- Set minimum and maximum height thresholds
- Visualize only specific height ranges
- Hide areas outside your target range (appear transparent)
- Get information only for visible areas
Available Height Values
The filter provides discrete height values for precise analysis:
0m, 1m, 2m, 3m, 5m, 7m, 10m, 12m, 15m, 18m, 20m, 25m, 30m, 35m, 40m, 50m, 60m, 70m, 80m, 90m, 100m, 100+
Using the Filter
Step 1: Open the Canopy Height Model Layer
- Locate the Canopy Height Model (100m) layer in your Layers Panel
- Ensure the layer is visible (checkbox enabled)
Step 2: Access the Filter Controls
- Click on the Canopy Height Model (100m) layer in the Layers Panel
- Expand the layer panel to see the Canopy Height Filter section
- You'll see a dual-handle slider showing the current range
Step 3: Set Your Height Range
Using the Slider:
- Drag the left handle to set the minimum height
- Drag the right handle to set maximum height
- The range display shows your current selection (e.g., "Range: 0m - ∞")
- The map updates automatically as you adjust
Reset to Default:
- Click the Reset Range button to return to 0m - ∞
Step 4: Analyze Results
- Colored areas: Canopy heights within your selected range
- Transparent areas: Heights outside your range (filtered out)
- Click on the map: Get height information for visible areas only
- Popup data: Only shown for areas within your filter range
Common Use Cases
Forest Management
Identify Mature Forest Stands
- Set range: 50m - ∞
- Shows: All mature and tall forest areas
- Use for: Harvest planning, timber assessment
Locate Regeneration Areas
- Set range: 0m - 15m
- Shows: Young growth and saplings
- Use for: Replanting assessment, growth monitoring
Plan Selective Harvesting
- Set range: 35m - 60m
- Shows: Standard mature forest
- Use for: Selective logging operations
Environmental Analysis
Study Vertical Forest Structure
- Compare multiple ranges: 0-25m, 25-50m, 50m+
- Understand: Forest layering and complexity
- Apply to: Habitat assessment
Analyze Habitat Complexity
- Use overlapping ranges
- Identify: Multi-layered forest areas
- Support: Biodiversity studies
Monitor Forest Growth
- Set specific range for target age class
- Track: Canopy development over time
- Document: Succession patterns
Planning Applications
Visual Impact Assessment
- Set range: 60m - ∞
- Identify: Tall trees that may affect views
- Use for: Screening analysis
Buffer Zone Planning
- Set range based on screening requirements
- Visualize: Effective visual barriers
- Plan: Vegetation buffers
Wildlife Corridor Analysis
- Set range: 35m - ∞
- Identify: Continuous canopy connectivity
- Design: Wildlife movement corridors
Filter Strategies
Start Broad, Then Narrow
Begin with major categories
- Understory: 0-30m
- Canopy: 30-60m
- Tall forest: 60m+
Identify areas of interest
- Note patterns and concentrations
Refine with specific ranges
- Example: 45m - 65m for detailed mature forest
Use precise ranges
- Fine-tune for specific analysis needs
Consider Your Map Scale
- Large areas: Use broad ranges (25m increments)
- Local analysis: Use narrow ranges (5-10m increments)
- Detailed studies: Use precise custom ranges
- Overview: Use major forest categories
Compare Multiple Ranges
- Apply first range (e.g., 0-25m)
- Note the pattern
- Change to second range (e.g., 25-50m)
- Compare the distributions
- Identify forest structure differences
Tips for Best Results
Choosing the Right Range
For Timber Assessment:
- Use: 50m+ for merchantable timber
- Use: 15-35m for future harvest planning
- Use: 0-15m for regeneration monitoring
For Ecological Studies:
- Use: Multiple ranges for habitat layers
- Use: Narrow ranges for specific species needs
- Use: Broad ranges for general structure
For Visual Analysis:
- Use: 40-70m for dominant canopy
- Use: 60m+ for view obstruction
- Use: Relevant sight-line heights for screening
Combine with Other Layers
- Aerial imagery: Provides visual context
- Property boundaries: Define analysis areas
- Roads: Identify access points
- Slope layers: Understand terrain relationships
Understand the Display
- Color gradient: Shows height variation within range
- Transparent areas: Outside filter range, no data shown
- Opacity slider: Adjust layer transparency for better viewing
- Legend: Shows color-to-height relationship
Frequently Asked Questions
Q: Why don't I see popup data when I click? A: You're clicking on a transparent area outside your filter range. Only visible (colored) areas show popup data.
Q: How do I see all heights again? A: Click the "Reset Range" button to return to 0m - ∞ (shows all canopy heights).
Q: Can I export filtered data? A: The filter only affects the display.
Q: What does ∞ (infinity) mean? A: It represents "100+ meters"—all canopy heights above 100m.
Q: The map updates slowly when I move the slider A: This is normal—the system waits until you stop moving the slider before updating the map display.
Q: How accurate are the height measurements? A: The height data comes from Visual Tas with 50cm × 50cm resolution per pixel, providing very detailed canopy measurements. The data covers PTPZ Land with a 100m buffer zone around it.
Q: What area does this data cover? A: The canopy height data covers PTPZ Land and extends 100 meters beyond its boundaries to provide context for edge analysis.