eccodes/definitions/grib1/grid_definition_1.def

# (C) Copyright 2005- ECMWF.

# GRID DEFINITION Mercator projection
# grib 1 -> 2
constant gridDefinitionTemplateNumber     = 20;

signed[2] Ni : dump;
alias numberOfPointsAlongAParallel=Ni;
alias Nx=Ni;
alias geography.Ni=Ni;
alias numberOfPointsAlongXAxis=Ni;

signed[2] Nj : dump;
alias numberOfPointsAlongAMeridian=Nj;
alias Ny=Nj;
alias geography.Nj=Nj;
alias numberOfPointsAlongYAxis=Nj;

include "grib1/grid_first_last_resandcomp.def";

signed[3] Latin : edition_specific,no_copy;
meta geography.LaDInDegrees scale(Latin,oneConstant,grib1divider,truncateDegrees) : dump;

pad padding_grid1_1(1);

# for change_scanning_direction
alias yFirst=latitudeOfFirstGridPointInDegrees;
alias yLast=latitudeOfLastGridPointInDegrees;
alias xFirst=longitudeOfFirstGridPointInDegrees;
alias xLast=longitudeOfLastGridPointInDegrees;

include "grib1/scanning_mode.def";

signed[3] DiInMetres: dump;
alias longitudinalDirectionGridLength=DiInMetres;
alias Di=DiInMetres;
alias geography.DiInMetres=DiInMetres;
alias DxInMetres = DiInMetres;

signed[3] DjInMetres: dump;
alias latitudinalDirectionGridLength=DjInMetres;
alias Dj=DjInMetres;
alias geography.DjInMetres=DjInMetres;
alias DyInMetres = DjInMetres;

constant orientationOfTheGridInDegrees=0;

pad padding_grid1_2(8);

meta numberOfDataPoints number_of_points(Ni,Nj) : dump;
alias numberOfPoints=numberOfDataPoints;
meta numberOfValues number_of_values(values,bitsPerValue,numberOfDataPoints,bitmapPresent,bitmap,numberOfCodedValues) : dump;
#alias ls.valuesCount=numberOfValues;

iterator mercator(numberOfPoints,missingValue,values,
          radius,Ni,Nj,
          latitudeOfFirstGridPointInDegrees, longitudeOfFirstGridPointInDegrees,
          LaDInDegrees,
          latitudeOfLastGridPointInDegrees, longitudeOfLastGridPointInDegrees,
          orientationOfTheGridInDegrees,
          DiInMetres,DjInMetres,
          iScansNegatively,
          jScansPositively,
          jPointsAreConsecutive,
          alternativeRowScanning);

nearest mercator(values,radius,Nx,Ny);

meta latLonValues latlonvalues(values);
alias latitudeLongitudeValues=latLonValues;
meta latitudes latitudes(values,0);
meta longitudes longitudes(values,0);
meta distinctLatitudes latitudes(values,1);
meta distinctLongitudes longitudes(values,1);