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Interpolate a fieldset at a given point. The method used is bilinear interpolation. If a list is given, it must contain two numbers - latitude and longitude. If two numbers are given, the first is the latitude, the second the longitude. The field must be a gridded field. If the fieldset has only one field, a number is returned; otherwise a list is returned. Where it is not possible to generate a sensible value due to lack of valid data in the fieldset, nil is returned. Note that a similar function, nearest_gridpoint() , also exists.
geopoints interpolate ( fieldset,geopoints )
Generates a set of geopoints from a field. The first field of the input fieldset is used. The field is interpolated for each position of the geopoints given as a second parameter. The method used is bilinear interpolation. The output geopoints take their date, time and level from the fieldset. Where it is not possible to generate a sensible value due to lack of valid data in the fieldset, the internal geopoints missing value is used (this value can be checked for with the built-in variable geo_missing_value or removed with the function remove_missing_values). Note that a similar function, nearest_gridpoint() , also exists.
fieldset Anchor laplacian laplacian laplacian (f: fieldset)
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Note that a similar function, interpolate(), also exists.
geopoints nearest_gridpoint ( fieldset,geopoints )
Generates a set of geopoints from a field. The first field of the input fieldset is used. The result is a set of geopoints whose values are those of the nearest gridpoints in the field to the geopoints given as a second parameter. Where it is not possible to generate a sensible value due to lack of valid data in the fieldset, the internal geopoints missing value is used (this value can be checked for with the built-in variable geo_missing_value or removed with the function remove_missing_values). Note that a similar function, interpolate() , also exists.
list Anchor nearest_gridpoint_info nearest_gridpoint_info nearest_gridpoint_info ( fieldset,list[,string] )
list nearest_gridpoint_info ( fieldset,number,number[,string] )
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The function computes:
| Mathdisplay |
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\int_{bottomp_{top}}^{p_{topbottom}} f \frac{dp}{g} |
where
fis the fieldsetpis the pressuregis the acceleration of gravity (9.80665 m/s2).
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