latlon2cell: Get grid cell (x and y) for given lon and lat coordinates of...

In neumannd/riverdata: Reads river runoff and load data in different formats into R

Description

We insert lat and lon coordinates (note the order: not lon and lat) and provide grid information as parameter 'grid'. 'grid' is a nested list, which contains sub-lists denoted as 'lon' and 'lat'. The sub-list 'lon' has to contain numeric values denoted as 'lonw' (westerly boundary of the grid), 'lone' (easterly boundary of the grid), and 'dlon' (delta-longitude; distance between two grid cells). The sub-list 'lat' has to contain numeric values denoted as 'latn' (northern boundary of the grid), 'lats' (southern boundary of the grid), 'dlat' (delta-latitude), and 'nlat' (the number of grid cells in latitudal direction). THE ORIGIN OF THE GRID IS CONSIDERED TO BE IN THE TOP LEFT CORNER.

Usage

latlon2cell(lat, lon, grid)

Arguments

lat	numeric (single value or 1d array); latitude coordinate
lon	numeric (single value or 1d array); longitude coordinate
grid	grid definition (see description or example for structure)

Value

list('x'=..., 'y'=...); list of x- and y-coordinates of the grid cells

Author(s)

Daniel Neumann, [e-mail]

Examples

  # grid definition
  grid <- list(lon = list(lonw=-5.0, lone=10.0, dlon=0.5),
              lat = list(lats=49.0, latn=65.0, dlat=0.5, nlat=(65.0-49.0)/0.5))
  
  # OR
  # grid <- get.infos.grids.hbm.basic()$coarse
  
  # some coordinates
  lon <- c(-4.9, -4.1, 5.6)
  lat <- c(64.9, 64.9, 53.2)
  
  # get grid cells 
  grid_cells <- latlon2cell(lat, lon, grid)
  # result should be:
  #  - grid_cells$x: 1, 2, 22
  #  - grid_cells$y: 1, 1, 24
  

neumannd/riverdata documentation built on March 4, 2020, 4:22 a.m.