<?php

$resultado = [
["lat" => 0.0,"lon" => 0.0,"horario" => "00:00",],
["lat" => 0.0,"lon" => 0.0,"horario" => "06:00",],
["lat" => 0.0,"lon" => 0.0,"horario" => "12:00",],
["lat" => 0.0,"lon" => 0.0,"horario" => "18:00",],
["lat" => 0.0,"lon" => 0.0,"horario" => "24:00",]];

$result = [];

foreach($resultado as $row)
{
    $result[] = [
        "latitude" => $row["lat"],
        "longitude" => $row["lon"],
        "conteudo" => $row["horario"]
    ];
}

var_export( $result );