Functions to convert among spatial indices

These functions convert among different ways of referencing locations in BirdFlow models and output. They convert among the spatial coordinates (x and y), raster row and col indices, and the index i along a location vector. latlon_to_xy() and xy_to_latlon() convert between WGS 1984 latitude and longitude and x and y coordinates in a BirdFlow object's coordinate reference system (CRS).

Usage

x_to_col(x, bf)

y_to_row(y, bf)

row_to_y(row, bf)

col_to_x(col, bf)

i_to_rc(i, bf)

i_to_row(i, bf)

i_to_col(i, bf)

i_to_x(i, bf)

i_to_y(i, bf)

i_to_xy(i, bf)

rc_to_i(row, col, bf)

xy_to_i(x, y, bf)

latlon_to_xy(lat, lon, bf)

xy_to_latlon(x, y, bf)

Arguments

x, y

x and y coordinates in the BirdFlow model's CRS. This typically represents an easting and northing in meters. For functions that require both x and y a two column matrix or data.frame containing x and y columns in that order can be passed to x in which case y should be omitted.

bf

A BirdFlow model.

row, col

The row and column index of a cell in the BirdFlow model and associated raster data. Alternatively, a two column matrix or data.frame containing row and column indices in columns 1 and 2 respectively can be passed to row in which case the col argument should be omitted.

i

The index along a state vector that contains the data for unmasked cells.

lat, lon

The latitude and longitude in WGS 1984 (EPSG:4326). A two column matrix or data frame can also be passed to lat.

Value

x_to_col(x, bf) and y_to_row(y, bf)

Return the column or row index that each x or y coordinate falls within.

row_to_y(row, bf) and col_to_x(col, bf)

Return the y or x coordinate of the center each row or column.

i_to_row(i, bf) and i_to_col(i, bf)

Return the row or column index corresponding to the vector state index, i.

i_to_rc(i, bf)

Returns a two column matrix of the row and column index in the raster corresponding to the index, i of the vector state.

i_to_x(i, bf) and i_to_y(i, bf)

Return the x or y coordinate from the vector state index, i.

i_to_xy(i, bf)

Returns a two column matrix of the x and y coordinates corresponding to the index, i of the vector state space.

rc_to_i(row, col, bf) and xy_to_i(x, y, bf)

Return the state space index corresponding to x and y coordinates or row and column indices.

latlon_to_xy(lat, lon, bf)

Returns a two column matrix of the x and y coordinates corresponding to the supplied latitude and longitude. The output is in the CRS of bf (crs(bf)).

xy_to_latlon(x, y, bf)

Returns a two column matrix of the latitude and longitude of points in WGS84 given their coordinates in the BirdFlow object's CRS.

Details

In general, these functions mirror NA input in output; and functions that return rows, columns, or the index (i) will return NA if the input isn't within the extent; or for (i) within the active cells.

For most CRSs longitude translates to the x coordinate and latitude to the y coordinate. The traditional order of coordinates latitude and longitude; row and column, and x and y are not consistent, but that is still what is used here, i.e. latitude, row, and y are generally correlated, and are first, first, and second in argument order.

See also

• expand_distr() converts a vector distribution into it's raster (matrix) equivalent or a matrix (representing multiple distributions) into an array equivalent.

• rasterize_distr() converts a vector distribution into a terra::SpatRaster - similar to those created by terra::rast().