avmap: Create a difference map compared to average

In jsta/DataflowR: Toolbox for Processing and Viewing Underway Dataflow Output

Create a difference map compared to average

Description

takes a survey date as input and searches the DF_Surfaces folder for maps of the same parameter within the range of 1-2 months from yearmon for each year. These surfaces are averaged and compared to the surface from yearmon.

Usage

avmap(yearmon, params, diffpath = NULL, avpath = NULL, percentcov = 0.6,
  tolerance = 1, fdir = getOption("fdir"))

Arguments

yearmon	survey of interest to compare against average
params	variable name generally choice of "sal" or "chlext"
diffpath	file.path to write output difference surface
avpath	file.path to write output average surface
percentcov	numeric account for the different raster extents by setting the percent of all surveys required before a pixel is included in difference from average computations
tolerance	numeric number of months on either side of yearmon to include in the set of surfaces averaged . defaults to 1.
fdir	character file path to local data directory

Details

resulting surfaces are written to disk if the avpath or diffpath arguments are specified

Examples

## Not run: 
avmap(yearmon = 201505, params = "sal", diffpath = file.path(getOption("fdir"),
"DF_Surfaces", 201505, paste0("diff", "sal", ".tif")),
 percentcov = 0.6, tolerance = 1)
avmap(yearmon = 201505, params = "sal")

## End(Not run)

jsta/DataflowR documentation built on Sept. 27, 2022, 11:13 p.m.