readXenium: Read 10X Xenium output as SpatialFeatureExperiment

In pachterlab/SpatialFeatureExperiment: Integrating SpatialExperiment with Simple Features in sf

Read 10X Xenium output as SpatialFeatureExperiment

Description

This function reads the standard 10X Xenium output into an SFE object.

Usage

readXenium(
  data_dir,
  sample_id = "sample01",
  image = c("morphology_focus", "morphology_mip"),
  segmentations = c("cell", "nucleus"),
  row.names = c("id", "symbol"),
  flip = c("geometry", "image", "none"),
  max_flip = "50 MB",
  filter_counts = FALSE,
  add_molecules = FALSE,
  min_phred = 20,
  BPPARAM = SerialParam(),
  file_out = file.path(data_dir, "tx_spots.parquet")
)

Arguments

data_dir	Top level output directory.
sample_id	A character sample identifier, which matches the sample_id in imgData. The sample_id will also be stored in a new column in colData, if not already present. Default = sample01.
image	Which image(s) to load, can be "morphology_mip", "morphology_focus" or both. Note that in Xenium Onboarding Analysis (XOA) v2, there is no longer "morphology_mip" and "morphology_focus" is a directory with 4 images corresponding to 4 channels: DAPI, "Cadherin", 18S, and Vimentin. So this argument is ignored for XOA v2.
segmentations	Which segmentation outputs to read, can be "cell", "nucleus", or both.
row.names	String specifying whether to use Ensembl IDs ("id") or gene symbols ("symbol") as row names. If using symbols, the Ensembl ID will be appended to disambiguate in case the same symbol corresponds to multiple Ensembl IDs. Always "symbol" if 'add_molecules = TRUE' because only gene symbols are used in the transcript spot files.
flip	To flip the image, geometry coordinates, or none. Because the image has the origin at the top left while the geometry has origin at the bottom left, one of them needs to be flipped for them to match. If one of them is already flipped, then use "none". The image will not be flipped if it's GeoTIFF.
max_flip	Maximum size of the image allowed to flip the image. Because the image will be loaded into memory to be flipped. If the image is larger than this size then the coordinates will be flipped instead.
filter_counts	Logical, whether to keep cells with counts > 0.
add_molecules	Logical, whether to add transcripts coordinates to an object.
min_phred	Minimum Phred score to keep spot. By default 20, the conventional threshold indicating "acceptable", meaning that there's 1 chance that the spot was decoded in error.
BPPARAM	A BiocParallelParam object specifying parallel processing backend and number of threads to use for parallelizable tasks: To load cell segmentation from HDF5 files from different fields of view (FOVs) with multiple cores. A progress bar can be configured in the BiocParallelParam object. When there are numerous FOVs, reading in the geometries can be time consuming, so we recommend using a server and larger number of threads. This argument is not used if use_cellpose = TRUE and the parquet file is present. To get the largest piece and see if it's larger than min_area when there are multiple pieces in the cell segmentation for one cell.
file_out	Name of file to save the geometry or raster to disk. Especially when the geometries are so large that it's unwieldy to load everything into memory. If this file (or directory for multiple files) already exists, then the existing file(s) will be read, skipping the processing. When writing the file, extensions supplied are ignored and extensions are determined based on 'dest'.

Value

An SFE object. If reading segmentations, the cell or nuclei segmentation will be saved to 'cell_boundaries_sf.parquet' and 'nucleus_boundaries_sf.parquet' respectively in 'data.dir' so next time the boundaries can be read much more quickly. If reading transcript spots ('add_molecules = TRUE'), then the reformatted transcript spots are saved to file specified in the 'file_out' argument, which is by default 'tx_spots.parquet' in the same directory as the rest of the data. If images are present, then the images will be of the BioFormatsImage class and not loaded into memory until necessary in later operations.

Note

Sometimes when reading images, you will see this error the first time: 'java.lang.NullPointerException: Cannot invoke "loci.formats.DimensionSwapper.setMetadataFiltered(boolean)" because "RBioFormats.reader" is null'. Rerun the code and it should work the second time.

Examples

library(SFEData)
library(RBioFormats)
fp <- tempdir()
dir_use <- XeniumOutput("v2", file_path = file.path(fp, "xenium_test"))
# RBioFormats issue
try(sfe <- readXenium(dir_use, add_molecules = TRUE))
sfe <- readXenium(dir_use, add_molecules = TRUE)
unlink(dir_use, recursive = TRUE)

pachterlab/SpatialFeatureExperiment documentation built on May 17, 2024, 12:24 a.m.