Source code for iwfm.nearest

# nearest.py
# Return nearest IWFM node to an (x,y) location
# Copyright (C) 2020-2026 University of California
# -----------------------------------------------------------------------------
# This information is free; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This work is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# For a copy of the GNU General Public License, write to the Free Software
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# -----------------------------------------------------------------------------


'''Find the nearest node to a point from a node dictionary.'''



def nearest(d_nodes, x, y):
    '''Find the nearest node to a point from a node dictionary.

    Parameters
    ----------
    d_nodes : dictionary
        key = model node, value = x and y locations

    x : float
        x location of point

    y : float
        y location of point

    Returns
    -------
    nearest : int
        node ID of node closest to (x,y)
    '''
    import math

    point = [x, y]
    dist = 9.9e30
    nearest = -1
    for key in d_nodes:
        pt = d_nodes[key]
        new_dist = math.hypot(point[0] - pt[0], point[1] - pt[1])  # Euclidean distance
        if dist > new_dist:
            dist = new_dist
            nearest = key
    return nearest