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Now one needs to decide where the "LAM grid" should be located on the "global grid".
It In general, it is best to center the "LAM grid" over the grid(!) equator of the "global grid" to keep the grid boxes as square as possible. However, if the LAM grid region is not too large and fairly close to or even covering the "real" equator, some people prefer not to rotate the grid and therefore shift the "LAM grid" a little north- or southward.
Imagine the "LAM grid" is a piece of paper and you want to pin it in a certain location on a global map. First you would put a pin in the piece of paper in the "reference point", defined by 'Grd_iref' and 'Grd_jref'. Then you would pin it at a certain location on the "global grid", defined by 'Grd_lon1' and 'Grd_lat1' (in longitude and latitude of the rotated grid!).
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