Data - Preparation#

This module allows you to create topological hedge layers:

  • A line layer representing the median axis of each polygon.

  • A point layer representing line extremities.

  • A polygon layer split at each node with a degree greater than or equal to 3.

These three layers together represent your hedge objects. The hedge geometries are linked via unique index fields created by this module:

  • pid – Polygon ID.

  • eid – Edge ID.

  • vid – Vertex ID.

Remark

These fields act as Primary Keys (PK) and Foreign Keys (FK):

  • A Primary Key (PK) is a unique identifier for each record in a table (e.g. each polygon, line, or point has its own unique ID).

  • A Foreign Key (FK) is a field that references a Primary Key in another table, creating a link between related data.

In HedgeTools, these IDs allow us to:

  • uniquely identify each geometry element (polygon, line, point)

  • maintain relationships between them (e.g. which line belong to a polygon, which points define a line) and build the hedge object.

An optional algorithm can be applied to simplify the median axis, reducing geometric irregularities and smoothing the line.

Hedge creation steps