问题
I'm trying to display geospatial data in a hexagonal grid on a Google Map.
In order to do so, given a hexagon tile grid size X I need to be able to convert ({lat, lng}) coordinates into the ({lat, lng}) centers of the hexagon grid tiles that contain them.
In the end, I would like to be able to display data on a Google Map like this:
Does anybody have any insight into how this is done?
I've tried porting this Python hexagon binning script, binner.py to Javascript but it doesn't seem to be working properly- the output values are all the same as the input ones.
For the sake of this example, I don't care if there are multiple polygons in a single location, I just need to figure out how to bin them into the correct coordinates.
Code below, (Plunker here!)
var map;
var pointCount = 0;
var locations = [];
var gridWidth = 200000; // hex tile size in meters
var bounds;
var places = [
[44.13, -69.51],
[45.23, -67.42],
[46.33, -66.53],
[44.43, -65.24],
[46.53, -64.15],
[44.63, -63.06],
[44.73, -62.17],
[43.83, -63.28],
[44.93, -64.39],
[44.13, -65.41],
[41.23, -66.52],
[44.33, -67.63],
[42.43, -68.74],
[44.53, -69.65],
[40.63, -70.97],
]
var SQRT3 = 1.73205080756887729352744634150587236;
$(document).ready(function(){
bounds = new google.maps.LatLngBounds();
map = new google.maps.Map(document.getElementById("map_canvas"), {center: {lat: 0, lng: 0}, zoom: 2});
// Adding a marker just so we can visualize where the actual data points are.
// In the end, we want to see the hex tile that contain them
places.forEach(function(place, p){
latlng = new google.maps.LatLng({lat: place[0], lng: place[1]});
marker = new google.maps.Marker({position: latlng, map: map})
// Fitting to bounds so the map is zoomed to the right place
bounds.extend(latlng);
});
map.fitBounds(bounds);
// Now, we draw our hexagons! (or try to)
locations = makeBins(places);
locations.forEach(function(place, p){
drawHorizontalHexagon(map, place, gridWidth);
})
});
function drawHorizontalHexagon(map,position,radius){
var coordinates = [];
for(var angle= 0;angle < 360; angle+=60) {
coordinates.push(google.maps.geometry.spherical.computeOffset(position, radius, angle));
}
// Construct the polygon.
var polygon = new google.maps.Polygon({
paths: coordinates,
position: position,
strokeColor: '#FF0000',
strokeOpacity: 0.8,
strokeWeight: 2,
fillColor: '#FF0000',
fillOpacity: 0.35,
geodesic: true
});
polygon.setMap(map);
}
// Below is my attempt at porting binner.py to Javascript.
// Source: https://github.com/coryfoo/hexbins/blob/master/hexbin/binner.py
function distance(x1, y1, x2, y2){
console.log(x1, y1, x2, y2);
result = Math.sqrt(((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2)));
console.log("Distance: ", result);
return result;
}
function nearestCenterPoint(value, scale){
div = (value / (scale / 2));
mod = value % (scale / 2);
if(div % 2 == 1){
increment = 1;
} else {
increment = 0;
}
rounded = (scale / 2) * (div + increment);
if(div % 2 === 0){
increment = 1;
} else {
increment = 0;
}
rounded_scaled = (scale / 2) * (div + increment)
result = [rounded, rounded_scaled];
return result;
}
function makeBins(data){
bins = [];
data.forEach(function(place, p){
x = place[0];
y = place[1];
console.log("Original location:", x, y);
px_nearest = nearestCenterPoint(x, gridWidth);
py_nearest = nearestCenterPoint(y, gridWidth * SQRT3);
z1 = distance(x, y, px_nearest[0], py_nearest[0]);
z2 = distance(x, y, px_nearest[1], py_nearest[1]);
console.log(z1, z2);
if(z1 > z2){
bin = new google.maps.LatLng({lat: px_nearest[0], lng: py_nearest[0]});
console.log("Final location:", px_nearest[0], py_nearest[0]);
} else {
bin = new google.maps.LatLng({lat: px_nearest[1], lng: py_nearest[1]});
console.log("Final location:", px_nearest[1], py_nearest[1]);
}
bins.push(bin);
})
return bins;
}
回答1:
Use google.maps.geometry.poly.containsLocation.
for (var i = 0; i < hexgrid.length; i++) {
if (google.maps.geometry.poly.containsLocation(place, hexgrid[i])) {
if (!hexgrid[i].contains) {
hexgrid[i].contains = 0;
}
hexgrid[i].contains++
}
}
Example based off this related question: How can I make a Google Maps API v3 hexagon tiled map, preferably coordinate-based?. The number in the white box in the center of each hexagon is the number of markers contained by it.
proof of concept fiddle
code snippet:
var map = null;
var hexgrid = [];
function initMap() {
var myOptions = {
zoom: 8,
center: new google.maps.LatLng(43, -79.5),
mapTypeControl: true,
mapTypeControlOptions: {
style: google.maps.MapTypeControlStyle.DROPDOWN_MENU
},
navigationControl: true,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map"),
myOptions);
createHexGrid();
var bounds = new google.maps.LatLngBounds();
// Seed our dataset with random locations
for (var i = 0; i < hexgrid.length; i++) {
var hexbounds = new google.maps.LatLngBounds();
for (var j = 0; j < hexgrid[i].getPath().getLength(); j++) {
bounds.extend(hexgrid[i].getPath().getAt(j));
hexbounds.extend(hexgrid[i].getPath().getAt(j));
}
hexgrid[i].bounds = hexbounds;
}
var span = bounds.toSpan();
var locations = [];
for (pointCount = 0; pointCount < 50; pointCount++) {
place = new google.maps.LatLng(Math.random() * span.lat() + bounds.getSouthWest().lat(), Math.random() * span.lng() + bounds.getSouthWest().lng());
bounds.extend(place);
locations.push(place);
var mark = new google.maps.Marker({
map: map,
position: place
});
// bin points in hexgrid
for (var i = 0; i < hexgrid.length; i++) {
if (google.maps.geometry.poly.containsLocation(place, hexgrid[i])) {
if (!hexgrid[i].contains) {
hexgrid[i].contains = 0;
}
hexgrid[i].contains++
}
}
}
// add labels
for (var i = 0; i < hexgrid.length; i++) {
if (typeof hexgrid[i].contains == 'undefined') {
hexgrid[i].contains = 0;
}
var labelText = "<div style='background-color:white'>" + hexgrid[i].contains + "</div>";
var myOptions = {
content: labelText,
boxStyle: {
border: "1px solid black",
textAlign: "center",
fontSize: "8pt",
width: "20px"
},
disableAutoPan: true,
pixelOffset: new google.maps.Size(-10, 0),
position: hexgrid[i].bounds.getCenter(),
closeBoxURL: "",
isHidden: false,
pane: "floatPane",
enableEventPropagation: true
};
var ibLabel = new InfoBox(myOptions);
ibLabel.open(map);
}
}
function createHexGrid() {
// === Hexagonal grid ===
var point = new google.maps.LatLng(42, -78.8);
map.setCenter(point);
var hex1 = google.maps.Polygon.RegularPoly(point, 25000, 6, 90, "#000000", 1, 1, "#00ff00", 0.5);
hex1.setMap(map);
var d = 2 * 25000 * Math.cos(Math.PI / 6);
hexgrid.push(hex1);
var hex30 = google.maps.Polygon.RegularPoly(EOffsetBearing(point, d, 30), 25000, 6, 90, "#000000", 1, 1, "#00ffff", 0.5);
hex30.setMap(map);
hexgrid.push(hex30);
var hex90 = google.maps.Polygon.RegularPoly(EOffsetBearing(point, d, 90), 25000, 6, 90, "#000000", 1, 1, "#ffff00", 0.5);
hex90.setMap(map);
hexgrid.push(hex90);
var hex150 = google.maps.Polygon.RegularPoly(EOffsetBearing(point, d, 150), 25000, 6, 90, "#000000", 1, 1, "#00ffff", 0.5);
hex150.setMap(map);
hexgrid.push(hex150);
var hex210 = google.maps.Polygon.RegularPoly(EOffsetBearing(point, d, 210), 25000, 6, 90, "#000000", 1, 1, "#ffff00", 0.5);
hex210.setMap(map);
hexgrid.push(hex210);
hex270 = google.maps.Polygon.RegularPoly(EOffsetBearing(point, d, 270), 25000, 6, 90, "#000000", 1, 1, "#ffff00", 0.5);
hex270.setMap(map);
hexgrid.push(hex270);
var hex330 = google.maps.Polygon.RegularPoly(EOffsetBearing(point, d, 330), 25000, 6, 90, "#000000", 1, 1, "#ffff00", 0.5);
hex330.setMap(map);
hexgrid.push(hex330);
var hex30_2 = google.maps.Polygon.RegularPoly(EOffsetBearing(EOffsetBearing(point, d, 30), d, 90), 25000, 6, 90, "#000000", 1, 1, "#ff0000", 0.5);
hex30_2.setMap(map);
hexgrid.push(hex30_2);
var hex150_2 = google.maps.Polygon.RegularPoly(EOffsetBearing(EOffsetBearing(point, d, 150), d, 90), 25000, 6, 90, "#000000", 1, 1, "#0000ff", 0.5);
hex150_2.setMap(map);
hexgrid.push(hex150_2);
var hex90_2 = google.maps.Polygon.RegularPoly(EOffsetBearing(EOffsetBearing(point, d, 90), d, 90), 25000, 6, 90, "#000000", 1, 1, "#00ff00", 0.5);
hex90_2.setMap(map);
hexgrid.push(hex90_2);
// This Javascript is based on code provided by the
// Community Church Javascript Team
// http://www.bisphamchurch.org.uk/
// http://econym.org.uk/gmap/
//]]>
}
google.maps.event.addDomListener(window, 'load', initMap);
// EShapes.js
//
// Based on an idea, and some lines of code, by "thetoy"
//
// This Javascript is provided by Mike Williams
// Community Church Javascript Team
// http://www.bisphamchurch.org.uk/
// http://econym.org.uk/gmap/
//
// This work is licenced under a Creative Commons Licence
// http://creativecommons.org/licenses/by/2.0/uk/
//
// Version 0.0 04/Apr/2008 Not quite finished yet
// Version 1.0 10/Apr/2008 Initial release
// Version 3.0 12/Oct/2011 Ported to v3 by Lawrence Ross
google.maps.Polygon.Shape = function(point, r1, r2, r3, r4, rotation, vertexCount, strokeColour, strokeWeight, Strokepacity, fillColour, fillOpacity, opts, tilt) {
var rot = -rotation * Math.PI / 180;
var points = [];
var latConv = google.maps.geometry.spherical.computeDistanceBetween(point, new google.maps.LatLng(point.lat() + 0.1, point.lng())) * 10;
var lngConv = google.maps.geometry.spherical.computeDistanceBetween(point, new google.maps.LatLng(point.lat(), point.lng() + 0.1)) * 10;
var step = (360 / vertexCount) || 10;
var flop = -1;
if (tilt) {
var I1 = 180 / vertexCount;
} else {
var I1 = 0;
}
for (var i = I1; i <= 360.001 + I1; i += step) {
var r1a = flop ? r1 : r3;
var r2a = flop ? r2 : r4;
flop = -1 - flop;
var y = r1a * Math.cos(i * Math.PI / 180);
var x = r2a * Math.sin(i * Math.PI / 180);
var lng = (x * Math.cos(rot) - y * Math.sin(rot)) / lngConv;
var lat = (y * Math.cos(rot) + x * Math.sin(rot)) / latConv;
points.push(new google.maps.LatLng(point.lat() + lat, point.lng() + lng));
}
return (new google.maps.Polygon({
paths: points,
strokeColor: strokeColour,
strokeWeight: strokeWeight,
strokeOpacity: Strokepacity,
fillColor: fillColour,
fillOpacity: fillOpacity
}))
}
google.maps.Polygon.RegularPoly = function(point, radius, vertexCount, rotation, strokeColour, strokeWeight, Strokepacity, fillColour, fillOpacity, opts) {
rotation = rotation || 0;
var tilt = !(vertexCount & 1);
return google.maps.Polygon.Shape(point, radius, radius, radius, radius, rotation, vertexCount, strokeColour, strokeWeight, Strokepacity, fillColour, fillOpacity, opts, tilt)
}
function EOffsetBearing(point, dist, bearing) {
var latConv = google.maps.geometry.spherical.computeDistanceBetween(point, new google.maps.LatLng(point.lat() + 0.1, point.lng())) * 10;
var lngConv = google.maps.geometry.spherical.computeDistanceBetween(point, new google.maps.LatLng(point.lat(), point.lng() + 0.1)) * 10;
var lat = dist * Math.cos(bearing * Math.PI / 180) / latConv;
var lng = dist * Math.sin(bearing * Math.PI / 180) / lngConv;
return new google.maps.LatLng(point.lat() + lat, point.lng() + lng)
}html,
body,
#map {
height: 100%;
width: 100%;
margin: 0px;
padding: 0px
}<script src="https://maps.googleapis.com/maps/api/js?libraries=geometry"></script>
<script src="https://google-maps-utility-library-v3.googlecode.com/svn/trunk/infobox/src/infobox.js"></script>
<div id="map"></div>来源：https://stackoverflow.com/questions/35468510/binning-data-into-a-hexagonal-grid-in-google-maps