# Coverage struct

Namespace: [Grasshopper2.Data](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.data.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
public readonly struct Coverage
```

A coverage specifies items, twigs or even entire trees using two integers. Coverages ignore actual paths, opting instead to identify elements using indices alone.

## Properties

- [Access](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/access.md): Gets the scope of coverage.
- [ItemIndex](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/itemindex.md): Gets the item index.
- [TwigIndex](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/twigindex.md): Gets the twig index.

## Methods

- [CreateFromAccess](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/createfromaccess.md): (static) Create the initial coverage implied by an access flag.
- [CreateItemCoverage](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/createitemcoverage.md): (static) Create coverage for a specific item.
- [CreateTreeCoverage](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/createtreecoverage.md): (static) Create coverage for an entire tree.
- [CreateTwigCoverage](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/createtwigcoverage.md): (static) Create coverage for a specific twig.
- [IncrementItem](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/incrementitem.md): Move the coverage to the next item. This method can only be called if the coverage access is Access.Item.
- [IncrementTwig](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/incrementtwig.md): Move the coverage to the next twig. This method can only be called if the coverage access is not Access.Tree.
- [IsValidCoverage](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/isvalidcoverage.md): (2 overloads, static) Test whether a specific coverage validly applies to a tree.
- [Slice](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/slice.md): Create a new tree based on this coverage of an existing tree.
- [ToString](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/tostring.md): Gets a description of this coverage.
- [TryIncrementItem](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/tryincrementitem.md): Try and increment a coverage to the next item index.
- [TryIncrementItems](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/tryincrementitems.md): (static) Try and increment all coverages whose [Coverage.Access](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/access.md) is set to [Access.Item](https://developer.rhino3d.com/api/gh2/type/grasshopper2.parameters.access.md) to the next item index.
- [TryIncrementTwig](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/tryincrementtwig.md): Try and increment a coverage to the next twig index.
- [TryIncrementTwigs](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/tryincrementtwigs.md): (static) Try and increment all coverages whose [Coverage.Access](https://developer.rhino3d.com/api/gh2/type/grasshopper2.data.coverage/access.md) is set to either [Access.Item](https://developer.rhino3d.com/api/gh2/type/grasshopper2.parameters.access.md) or [Access.Twig](https://developer.rhino3d.com/api/gh2/type/grasshopper2.parameters.access.md) to the next twig index.