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Specifies the coordinates of a transect line along which the cross-section is calculated. Enter coordinates (lat/long) of a line separated by a "/" (easternmost lat and long, westernmost lat and long). Alternatively, use the coordinate assist button.
The cross section is calculated from a set of geographical points taken along the input transect line. The point selection takes into consideration the resolution of the data and assures that a minimum of 64 points will be generated. Parameter Horizontal Point Mode selects the algorithm used to compute these points.
Note that it is possible to define a line through either pole by describing the line’s coordinates as follows. First, when specifying the latitudes of the two points, imagine that the latitude values go above 90 when you cross the North Pole and below -90 when you cross the South Pole. Next, if you wish a straight line, ensure that the two longitude values are the same as each other. An example demonstrates this. Say you wanted to defined a straight-line cross-section from 60S/25E to 60S/155W. This would be specified as -60/25/-120/25. The fact that one of the latitude values is below -90 indicates to Metview that a cross-section going through the South Pole is desired. Once this has been established, the fact that the two longitude values are identical tells Metview to use a straight line through the pole. If this is the intent, then only one unique longitude value is required, as the other one can be deduced. Giving Metview two different longitude values will cause a cross-section consisting of two curves to be produced.
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Specifies the parameter number of the W wind component data, if you are using non-ECMWF data - ECMWF uses specific parameter numbers different from the WMO ones. Enter whichever parameter number is appropriate for your data.
Horizontal Point Mode
Specifies how the geographical points along the input transect line will be computed. These points will be used to calculate the cross-section. Valid values are Interpolate and Nearest Gridpoint. Setting this option to Interpolate will create a regular (taking into consideration the resolution of the data and assuring that a minimum of 64 points will be generated) set of interpolated geographical points along the transect line. Setting this option to Nearest Gridpoint will filter the previous set of points by selecting only instead select the nearest points to from the original grid pointsdata.
Vertical Coordinates
Setting this option to User will enable the use of general height-based coordinates. In this mode, additional GRIB fields should be supplied (one per model level) where the values of the grid points represent the heights of their locations. Valid values are Default andUser.
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