gdal_grid {gdalUtilities}

Interface to GDAL's gdal_grid utility

Description

This function provides an interface mirroring that of the GDAL command-line app gdal_grid. For a description of the utility and the arguments that it takes, see the documentation at https://gdal.org/programs/gdal_grid.html.

Usage

gdal_grid(
  src_datasource,
  dst_filename,
  ...,
  ot,
  of,
  txe,
  tye,
  tr,
  outsize,
  a_srs,
  zfield,
  z_increase,
  z_multiply,
  a,
  spat,
  clipsrc,
  clipsrcsql,
  clipsrclayer,
  clipsrcwhere,
  l,
  where,
  sql,
  co,
  q,
  config_options = character(0),
  dryrun = FALSE
)

Arguments

src_datasource

Character. Path to a GDAL-supported readable datasource.

dst_filename

Character. Path to a GDAL-supported output file.

...

Here, a placeholder argument that forces users to supply exact names of all subsequent formal arguments.

ot, of, txe, tye, tr, outsize, a_srs, zfield, z_increase, z_multiply

See the GDAL project's gdal_grid documentation for details.

a, spat, clipsrc, clipsrcsql, clipsrclayer, clipsrcwhere

See the GDAL project's gdal_grid documentation for details.

l, where, sql, co, q

See the GDAL project's gdal_grid documentation for details.

config_options

A named character vector with GDAL config options, of the form c(option1=value1, option2=value2). (See here for a complete list of supported config options.)

dryrun

Logical (default FALSE). If TRUE, instead of executing the requested call to GDAL, the function will print the command-line call that would produce the equivalent output.

Value

Silently returns path to dst_filename.

Author(s)

Joshua O'Brien

Examples

## Set up file paths
td <- tempdir()
dem_file <- file.path(td, "dem.csv")
vrt_header_file <- file.path(td, "tmp.vrt")
out_raster <- file.path(td, "tmp.tiff")

## Create file of points with x-, y-, and z-coordinates
pts <-
    data.frame(Easting = c(86943.4, 87124.3, 86962.4, 87077.6),
               Northing = c(891957, 892075, 892321, 891995),
               Elevation = c(139.13, 135.01, 182.04, 135.01))
write.csv(pts, file = dem_file, row.names = FALSE)

## Prepare a matching VRT file
vrt_header <- c(
'<OGRVRTDataSource>',
'  <OGRVRTLayer name="dem">',
paste0('    <SrcDataSource>',dem_file,'</SrcDataSource>'),
'    <GeometryType>wkbPoint</GeometryType>',
'    <GeometryField encoding="PointFromColumns" x="Easting" y="Northing" z="Elevation"/>',
'  </OGRVRTLayer>',
'</OGRVRTDataSource>'
)
cat(vrt_header, file = vrt_header_file, sep = "\n")

## Test it out
gdal_grid(src_datasource = vrt_header_file,
          dst_filename = out_raster,
          a = "invdist:power=2.0:smoothing=1.0",
          txe = c(85000, 89000), tye = c(894000, 890000),
          outsize = c(400, 400),
          of = "GTiff", ot = "Float64", l = "dem")

## Check that it works
if(requireNamespace("terra", quietly = TRUE)) {
    library(terra)
    plot(rast(out_raster))
    text(Northing ~ Easting, data = pts,
         labels = seq_len(nrow(pts)), cex = 0.7)
}