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Returns geopoints with the value of each point being the distance in meters from the given geographical location. The location may be specified by supplying either two numbers (latitude and longitude respectively) or a 2-element list containing latitude and longitude in that order. The location should be specified in degrees. A geopoint with either latitude or longitude set to missing value will have a distance of missing value.
Anchor filter filter
geopoints filter ( geopoints,geopoints )
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Generates a set of geopoints from a field. The first parameter must contain a single field. The field is interpolated for each position of 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 ). This function will return a missing value where the geopoints have missing lat/lon.
Anchor latitudes latitudes
vector latitudes ( geopoints )
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Computes the mean of the geopoints. Missing values are bypassed in this calculation. If there are no valid values, then nil is returned.
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geopoints mask ( geopoints,list )
Creates a geopoints variable containing point values of 0 or 1 according to whether they are inside (1) or outside (0) a defined geographical area.
The list parameter must contain exactly four numbers representing a geographical area. These numbers should be in the order north, west, south and east (negative values for western and southern coordinates). Points with missing latitudes or longitudes are considered to be outside any area. See the documentation for the fieldset version of this function to see how to compose more complex regions than a simple rectangular area.
Anchor nearest_gridpoint nearest_gridpoint
geopoints nearest_gridpoint ( fieldset,geopoints )
Generates a set of geopoints from a field. The first field of the input fieldset
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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 locations are from the original geopoints, but 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). This function will return a missing value where the geopoints have missing lat/lon.
Anchor offset offset
geopoints offset ( geopoints,number,number )
geopoints offset ( geopoints,list)
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Returns a new geopoints variable that contains just one instance of any duplicate geopoint. Two geopoints are considered to be duplicates of each other if the files have the same format and the points have the same coordinates, height, date, time and valuestime and values.
Anchor remove_missing_latlons remove_missing_latlons
geopoints remove_missing_latlons ( geopoints )
Returns a new geopoints variable that contains just the points that do not have missing latitudes or longitudes from the input geopoints variable.
Anchor remove_missing_values remove_missing_values
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Returns a geopoints variable containing the same locations (latitude, longitude and height) as the second geopoints variable, but whose values are from the first geopoints variable (or a missing value if point not found in the first variable). Note that the resulting geopoints variable is sorted in the same way as performed by the geosort() function. This means that you need to be careful if performing functions between the results of a subsample() operation and another geopoints variable; if the locations in the two geopoints are the same, then you should geosort() the second geopoints beforehand. Points with missing latitudes or longitudes will still be in the output, but the rule is that such a point is defined not to be at the same location as another point, even if its lat/lon are also missing. Advice: remove missing lat/lon points using remove_missing_latlons() before using subsample() or geosort().
You can use function remove_missing_values() if you need to get rid of the missing valued points in the returned geopoints variable.
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