Convex Hull

Applicability:

• Cadcorp SIS Map Modeller
• Cadcorp SIS Map Editor
• Cadcorp SIS ActiveX Modeller

Ribbon Group:

Create-Edit

Conditions for use:

• Item Class: All item classes
• Number selected: 1
• Minimum item status: Editable

Associated commands:

• Add Geometry
• Decompose
• Fill
• Process
• Remove Geometry
• Unfill

Description:

 Convex Hull converts the selected items into convex Polygon, LineString or Point items.

Convex Hull draws a convex outline around the selected geometry. This usually results in a Polygon item, but a convex hull created from a point item is a point, and a convex hull from a single LineString segment is a LineString.

If you select multiple LineStrings or points, you can create a convex hull from these if you first convert them to a MultiLineString or multi-point item, using, for example, Union.

A convex hull is the convex shape surrounding the MultiLineString or multi-point, as though each point is a nail and the boundary is a rubber band:

Alternatively, if you are using points in Map Modeller, you can generate a TIN:

See Creating a TIN from a grid.

This command is part of the OGC Simple Features Specification.

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