Disaggregated object width¶
Summary¶
Calculate a poylgon width (ex. active channel or valley bottom) with the VariableLengthTransects tool and resume the result by DGO.
Tags:metric, width, dgo, polygon, transects
Usage¶
Algorithm:
- Create orthogonal transects from medial axis DGOs, spaced by the sampling interval and with a length defined by MAX_WIDTH parameter
- Intersect transects by input polygon and measure length of each resulting intersection
- Use the QGIS “Statistics by category” tool to calculate statistics by DGO
To simply make orthogonal transects along a medial axis, use directly the VariableLengthTransect tool.
Parameters¶
| Parameter | Description | Type |
|---|---|---|
Disaggregated objects to measure
INPUT_POLYGONS
|
Input disaggregated polygons | Polygon |
Disaggregated axis along which the measurements will be made perpendicularly
INPUT_MEDIAL_AXIS
|
Axis of the polygon you want to compute the width. The measurement will be made perpendiculary to this axis | LineString |
DGO FID field on objects
INPUT_POLYGONS_FID
|
Field containing DGOs ID in the polygons layer
Default value: DGO_FID
|
Field |
DGO FID field on axis
INPUT_MEDIAL_AXIS_FID
|
Field containing DGOs ID in the axis layer
Default value: DGO_FID
|
Field |
Length between sampling transects
SAMPLING_INTERVAL
|
Interval between two width measures along the axis.
Default value: 5
|
Number |
Maximum transects width
MAX_WIDTH
|
Maximum width of the polygon to measure (eq. maximum transects length)
Default value: 1000.0
|
Number |
Output measurement summary table
OUTPUT_TABLE
|
Output statistics on the measurement transects of each DGOs. The "mean" field contains the mean transect length (eq. the min width) for this DGO | Table |
Output measurement transects
OUTPUT_TRANSECTS
(Optional)
|
Output measurement transects | LineString |