3 - Generate tree cover#

Algorithm ID: hedgetools:generatetreecover

This tool generates a tree cover raster and vector layer using the DHM mask and NDVI mask obtained from Generate DHM and Generate NDVI, respectively. It intersects both masks, retaining only vegetation above the height threshold used to create the DHM mask.

The vector layer is generated from the sieved raster if a sieve operation is performed.

Parameters#

Label

Name

Type

Description

Input DHM mask

DHM

[raster]

Binary DHM mask raster.

DHM band

DHM_BAND

[raster band]
Default: 1

Band of the binary DHM raster to use in case of multiband.

Input NDVI mask

NDVI

[raster]

Binary NDVI mask raster.

NDVI band

NDVI_BAND

[raster band]
Default: 1

Band of the binary NDVI raster to use in case of multiband.

Extent of the study area
Optional

EXTENT

[extent]

Input extent from a layer, canvas, or other source to clip the rasters.

Compute sieved tree cover mask

SIEVE

[boolean]
Default: True

If enabled, the tree cover mask is sieved to remove small holes. Recommended to reduce noise in vegetation layers.

Threshold sieve value (pixel number)

THRESHOLD_SIEVE

[numeric: integer]
Default: 100

Minimum number of pixels for a feature to be kept in the sieved mask.

Handling of extent differences

EXTENT_OPT

[enumeration]
Default: 0

Determines how the tool handles differing DSM and DTM extents:

  • 0: Ignore – Only check input dimensions – raise error if dimensions differ.
  • 1: Fail – Check both CRS and dimensions – raise error if not equal.
  • 2: Union – Execute algorithm on the union of inputs.
  • 3: Intersect – Execute on intersection – raise error if no overlap.

Output resolution (meters)
Optional

RESOLUTION

[numeric: double]
Default: [same as input]

Change the output raster resolution to the desired value.

Resampling method
Optional

RESAMPLING

[enumeration]
Optional
Default: 0

Resampling method for output resolution:

  • 0: None
  • 1: Nearest Neighbour
  • 2: Bilinear (2x2 Kernel)
  • 3: Cubic (4x4 Kernel)
  • 4: Cubic B-Spline (4x4 Kernel)
  • 5: Lanczos (6x6 Kernel)
  • 6: Average
  • 7: Mode
  • 8: Maximum
  • 9: Minimum
  • 10: Median
  • 11: First Quartile (Q1)
  • 12: Third Quartile (Q3)

Output tree cover raster

OUTPUT_TREE_COVER

[raster]
Default: [Create temporary layer]

Output raster.

Output sieve tree cover raster

OUTPUT_SIEVE

[raster]
Default: [Create temporary layer]

Output raster.

Output vector tree cover

OUTPUT_VECTOR

[vector: polygon]
Default: [Create temporary layer]

Polygon vector layer.

Outputs#

Label

Name

Type

Description

Output tree cover raster

OUTPUT_TREE_COVER

[raster]

Tree cover raster. Intersection of the DHM and NDVI masks.

Output sieve tree cover raster

OUTPUT_SIEVE

[raster]

Tree cover raster with small holes removed based on the sieve threshold.

Output vector tree cover

OUTPUT_VECTOR

[vector: polygon]

Vectorized tree cover used in subsequent algorithms.