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In irregular grids the grid has a fixed number of rows and columns, but the cell height and width is not equal in each row and column. For these grids additional information is required on the location of each individual cell in the grid to allow display in the grids display as well as for use in the spatial interpolation routine.
For regular grids it is sometimes not required to add the location to the grids.xml when you only want to import/export the grid. Most grid transformations will not work when the output location is missing in the grids.xml. Regular grids that need a custom projection (projectionFile, polarStereoGraphic, geostationarySatelliteView, transverseMercator, mercator, albersEqualArea, azimuthalEquidistant, lambertAzimuthalEqualArea, rotatedCartesian, lambertConformalConic, rotatedSouthPole, rotatedNorthPole, rotatedCartesian, azimuthalEquidistant) should ALWAYS be listed in the grids.xml. The grid geometry should be available in the imported file (netcdf/grib).
When available on the file system, the name of the XML file is for example:
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