eccodes/definitions/grib1/scanning_mode.def

constant isGridded = true;

# Scanning mode
flags[1] scanningMode 'grib1/8.table' : edition_specific,no_copy;

# Not flagbit numbers 7 to 0, while wmo is 1 to 8
flagbit iScansNegatively(scanningMode,7)  : dump;
flagbit jScansPositively(scanningMode,6)  : dump;
flagbit jPointsAreConsecutive(scanningMode,5)  : dump;
constant alternativeRowScanning=0 : dump;

transient iScansPositively = !iScansNegatively : constraint;
transient jScansNegatively = !jScansPositively : constraint;

alias geography.iScansNegatively=iScansNegatively;
alias geography.jScansPositively=jScansPositively;
alias geography.jPointsAreConsecutive=jPointsAreConsecutive;

flagbit scanningMode4(scanningMode,4) = 0: read_only;
flagbit scanningMode5(scanningMode,3) = 0: read_only;
flagbit scanningMode6(scanningMode,2) = 0: read_only;
flagbit scanningMode7(scanningMode,1) = 0: read_only;
flagbit scanningMode8(scanningMode,0) = 0: read_only;

meta swapScanningX change_scanning_direction( values,Ni,Nj,
                 iScansNegatively,jScansPositively,
                 xFirst,xLast,x) : edition_specific,hidden,no_copy;
alias swapScanningLon = swapScanningX;

meta swapScanningY change_scanning_direction( values,Ni,Nj,
                 iScansNegatively,jScansPositively,
                 yFirst,yLast,y) : edition_specific,hidden,no_copy;
alias swapScanningLat = swapScanningY;

transient swapScanningAlternativeRows = 0; # Not available in grib1

if (jPointsAreConsecutive) {
    alias numberOfRows=Ni;
    alias numberOfColumns=Nj;
} else {
    alias numberOfRows=Nj;
    alias numberOfColumns=Ni;
}