# 3-dimensional objects

#### Adam B. Smith

#### 2025-06-19

fasterRaster has limited support for 3-dimensional `GRaster`s and `GVector`s. A `GRaster` is like a multi-layered raster, except that layers contain values in “voxels” (3-dimensional pixels), where each layer has a z-resolution, in addition to its normal x- and y-resolutions. These layers are called “depths”. A 3-dimensional vector has a z-dimension, so any point (i.e., an actual point, or points that together define a line or polygon) has a third dimension. You can test if an object is 3-dimensional using `topology()`, `is.2d()`, or `is.3d()`, or by looking at its metadata (i.e., just enter the name of the object in R and look at what is displayed).

Thus far, no functions that handle 3-dimensional `GRaster`s or `GVector`s have been tested. Some functions like `spatSample()` have arguments that allow you to do something with a z-component. Also, some of the “getter” functions can report information about the third dimension of a `GRaster` or `GVector`.

Three-dimensional `GRaster`s and `GVector`s should (?… remember, no testing yet!) work with most functions. In some cases, the third dimension will be ignored or removed. You should get a warning in these cases.

## fasterRaster functions that specifically work with 3-dimensional objects

Function | Object type
--- | ---
`bottom()` | `GRaster` or `GVector`
`dim3d()` | `GRaster`
`is.2d()` | `GRaster` or `GVector`
`is.3d()` | `GRaster` or `GVector`
`ncell3d()` | `GRaster`
`ndepth()` | `GRaster`
`res3d()` | `GRaster`
`top()` | `GRaster` or `GVector`
`topology()` | `GRaster` or `GVector`
`zext()` | `GRaster` or `GVector`
`zres()` | `GRaster`

~ FINIS ~