MeteoIODoc 20240411.d3bdb3cb

Format

This reads a grid file in PGM format (see http://www.fileformat.info/format/pbm/egff.htm). This is a graphic format that is supported by a wide range of graphics programs (Gimp, Irfanview, Paint Shop Pro, gqview, etc). This allows to write a grid as an image (one pixel equals one cell), read an image as a grid (useful for creating synthetic DEMs). Since there is no geolocalization information in this format, such data is either encoded as a comment (when writing a file) or read from io.ini (for reading). Finally, the naming scheme for meteo grids should be: YYYY-MM-DDTHH.mm_{MeteoGrids::Parameters}.pgm

Please keep in mind that only a finite number of greyscales are used, making a discretization of the data. Moreover, we consider that a color of "0" is NODATA.

Units

Cellsize is in meters, x/y coords in the section's coordinate system.

Keywords

This plugin uses the following keywords:

  • COORDSYS: coordinate system (see Coords); [Input] and [Output] section
  • COORDPARAM: extra coordinates parameters (see Coords); [Input] and [Output] section
  • GRID2DPATH: meteo grids directory where to read/write the grids; [Input] and [Output] sections
  • PGM_XCOORD: lower left x coordinate; [Input] section
  • PGM_YCOORD: lower left y coordinate; [Input] section
  • PGM_CELLSIZE: cellsize in meters; [Input] section
  • PGM_MIN: minimum value in real world coordinates to match with the minimum value read out of the PGM file (such minimum being greater than 0 because 0 is NODATA)
  • PGM_MAX: maximum value in real world coordinates to match with the maximum value read out of the PGM file

Example:

[Input]
DEM = PGM
DEMFILE = ./input/surface-grids/synthetic.pgm
PGM_XCOORD = 479500.
PGM_YCOORD = 73500.
PGM_CELLSIZE = 1000.
PGM_MIN = 193.
PGM_MAX = 4204.