dash.closest.site

Returns the coordinates of sites closest to a set of coordinates

Syntax



coordinates = dash.closest.site(coordinates, siteCoordinates)


[coordinates, siteIndices] = dash.closest.site(…)

Description



coordinates = dash.closest.site(coordinates, siteCoordinates)

Searches through latitude-longitude points to find the points that are closest to a set of latitude-longitude coordinates. The first input is the set of coordinates for which to find the closest points. The second input lists the set of available latitude-longitude coordinates. This method is often used to locate the elements of a non-spatially gridded dataset that are closest to a specific set of coordinates.

This function uses a haversine function to calculate the distance between sites. Since the haversine function is agnostic to longitude coordinate systems, you may use longitudes on -180:180, 0:360, or even a mix of both coordinate systems.



[coordinates, siteIndices] = dash.closest.site(…)

Also returns the index of the closest site within the set of examined points. These indices can be used to index into the closest element

Input Arguments

coordinates

numeric matrix [nCoordinates x 2]
A set of latitude-longitude coordinates in decimal degrees. The method will search for site coordinates that are closest to these points. A numeric matrix with two columns. The first column holds the latitude points, and the second column is longitude.

siteCoordinates

numeric matrix
A second set of latitude-longitude coordinates in decimal degrees. The method will determine which of these site coordinates is closest to each of the coordinate in the first input.

Output Arguments

coordinates

numeric matrix [nCoordinates x 2]
The site coordinate closest to each of the input coordinates. First column is latitude, second column is longitude.

siteIndices

vector, linear indices [nCoordinates]
The index of the site coordinate closest to each coordinate. These indices are relative to the rows of the “siteCoordinates” input.