dot_flip_y: Flip values on the y-axis direction, and negate the...

In plotthis: High-Level Plotting Built Upon 'ggplot2' and Other Plotting Packages

Flip values on the y-axis direction, and negate the Y-Coordinates of SpatRaster, SpatVector Object and data.frame

Description

These internal functions flip the y-coordinates of SpatRaster and SpatVector objects from the terra package. For rasters, the function vertically flips the raster and adjusts its extent accordingly. For vectors, the function negates the y-coordinates of all geometries. For data frames, it negates the values in the specified y column.

Usage

.flip_y(data, ...)

## S3 method for class 'SpatRaster'
.flip_y(data, ...)

## S3 method for class 'SpatVector'
.flip_y(data, ...)

## S3 method for class 'data.frame'
.flip_y(data, y = "y", ...)

Arguments

data	A SpatRaster or SpatVector object from the terra package, or a data.frame with x and y columns.

Details

These functions are intended for internal use to facilitate coordinate transformations. When visualizing spatial data, it is often necessary to flip the y-axis to put the origin at the top left corner. However, a lot of elements have to be visualized with ggplot2::geom_sf(), which won't work with ggplot2::scale_y_reverse(). See also this GitHub issue comment. So we need these functions to flip the values along the y-axis and negate the y-coordinates. This way, we can remove the negative sign from the y-axis labels to mimick the behavior of scale_y_reverse().#'

Value

For SpatRaster input, a SpatRaster object with flipped y-coordinates and adjusted extent. For SpatVector input, a SpatVector object with y-coordinates negated. For data.frame input, a data frame with the specified y column negated.

plotthis documentation built on June 21, 2025, 1:07 a.m.