From ordinary data frame to sf to construct SFE object — df2sf • SpatialFeatureExperiment

While the SpatialFeatureExperiment constructor and *Geometry replacement methods can convert properly formatted ordinary data frames into sf objects which are used to store the geometries internally, the user might want to do the conversion, check if the geometry is valid, and inspect and fix any invalid geometries.

Usage

df2sf(
  df,
  spatialCoordsNames = c("x", "y"),
  spotDiameter = NA,
  geometryType = c("POINT", "LINESTRING", "POLYGON", "MULTIPOINT", "MULTILINESTRING",
    "MULTIPOLYGON"),
  group_col = "group",
  id_col = "ID",
  subid_col = "subID",
  check = TRUE,
  ...
)

Arguments

df: An ordinary data frame, i.e. not sf. Or a matrix that can be converted to a data frame.
spatialCoordsNames: Column names in df that specify spatial coordinates.
spotDiameter: Spot diameter for technologies with arrays of spots of fixed diameter per slide, such as Visium, ST, DBiT-seq, and slide-seq. The diameter must be in the same unit as the coordinates in the *Geometry arguments. Ignored for geometries that are not POINT or MULTIPOINT.
geometryType: Type of geometry to convert the ordinary data frame to. If the geometry in df is de facto points, then this argument will be ignored and the returned sf will have geometry type POINT.
group_col: Column to indicate which coordinates for which MULTI geometry, such as to identify which MULTIPOLYGON or MULTIPOINT.
id_col: Column to indicate coordinates for which geometry, within a MULTI geometry if applicable, such as to identify which POLYGON or which polygon within a MULTIPOLYGON.
subid_col: Column to indicate coordinates for holes in polygons.
check: Logical, whether to check the input data frame for issues related to constructing the geometry of interese such as number of vertices per geometry. If FALSE, it will save a bit of time, which is useful when the input is already known to be good.
...: Other arguments passed to `sf::st_buffer`, mainly to make polygon shapes, eg Visium spot `endCapStyle = "ROUND"` and VisiumHD bin `endCapStyle = "SQUARE"`

Value

An sf object.

Examples

# Points, use spotDiameter to convert to circle polygons
# This is done to Visium spots
pts_df <- readRDS(system.file("extdata/pts_df.rds",
    package = "SpatialFeatureExperiment"
))
sf_use <- df2sf(pts_df, geometryType = "POINT", spotDiameter = 0.1)
# Linestring
ls_df <- readRDS(system.file("extdata/ls_df.rds",
    package = "SpatialFeatureExperiment"
))
sf_use <- df2sf(ls_df, geometryType = "LINESTRING")
# Polygon
pol_df <- readRDS(system.file("extdata/pol_df.rds",
    package = "SpatialFeatureExperiment"
))
sf_use <- df2sf(pol_df,
    geometryType = "POLYGON",
    spatialCoordsNames = c("V1", "V2")
)
# Multipolygon
mpol_df <- readRDS(system.file("extdata/mpol_df.rds",
    package = "SpatialFeatureExperiment"
))
sf_use <- df2sf(mpol_df,
    geometryType = "MULTIPOLYGON",
    spatialCoordsNames = c("V1", "V2")
)
# Multiple sample_ids present
multipts_df <- readRDS(system.file("extdata/multipts_df.rds",
    package = "SpatialFeatureExperiment"
))
sf_use <- df2sf(multipts_df, geometryType = "MULTIPOINT")