I am new to google earth engine and not so familiar with javascript. I want to display the cleared images (B4,B3,B2 bands) of Sentinel 2 by each dates in layers (each layer represent each date). The code is shown as below, but always get error 'no Band 4, constant band'. Can anyone help me to solve this problem? Thanks!
var lakes=table.geometry();
Map.centerObject(lakes, 15);
function maskS2clouds(image) {
var qa = image.select('QA60');
// Bits 10 and 11 are clouds and cirrus, respectively.
var cloudBitMask = 1 << 10;
var cirrusBitMask = 1 << 11;
// Both flags should be set to zero, indicating clear conditions.
var mask = qa.bitwiseAnd(cloudBitMask).eq(0)
.and(qa.bitwiseAnd(cirrusBitMask).eq(0));
return image.updateMask(mask).divide(10000);
}
var start = ee.Date('2015-06-20');
var finish = ee.Date('2018-06-01');
var collection = ee.ImageCollection('COPERNICUS/S2')
.filterDate(start, finish)
.filterBounds(lakes)
.filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 10))
.map(maskS2clouds);
var rgbVis = {
min: 0.0,
max: 0.3,
bands: ['B4', 'B3', 'B2'],
};
function addImage(imageL) { // display each image in collection
var id = imageL.id;
var image = ee.Image(imageL.id);
Map.addLayer(image.select(['B4','B3','B2']).clip(lakes),rgbVis,id)
}
collection.evaluate(function(collection) { // use map on client-side
print(collection.features);
collection.features.map(addImage);
})
I have a 12 month calendar. When a user clicks on the month I am calling my function toggleZoom
$monthNode.onclick = function(){toggleZoom(this)};
at the moment I cam controlling the zoom using this JS:
function toggleZoom(month) {
var zoomed = window.getComputedStyle(month).zIndex;
var m = document.getElementsByClassName("month");
for(var i = 0; i < m.length; i++)
{
m[i].style ='' ;
}
if (zoomed != 2) {
month.style = 'transform:scale(1.1,1.1); z-index:2';
}
}
Is there a cleaner way (one line of code, maybe) to reset all of my month classes to un-zoomed without looping through all 12? Something like document.getElementsByClassName("month").style=""
You can use the map() function to loop through your array in a single line without creating a for loop, like so: m.map(function(mo){ mo.style = ''; });
function toggleZoom(month) {
var zoomed = window.getComputedStyle(month).zIndex;
var m = document.getElementsByClassName("month");
m.map(function(mo){ mo.style = ''; });
if (zoomed != 2) {
month.style = 'transform:scale(1.1,1.1); z-index:2';
}
}
Or, using ES6's arrow function:
function toggleZoom(month) {
var zoomed = window.getComputedStyle(month).zIndex;
var m = document.getElementsByClassName("month");
m.map(mo => mo.style = '');
if (zoomed != 2) {
month.style = 'transform:scale(1.1,1.1); z-index:2';
}
}
I'm a social science person increasingly getting into web programming for data vis work so apologies if this question is dumb. I'm working on a polymaps implementation to visualize country level data over time. I reads in json temporal data and a geojson world map and spits out a quantile chloropleth map that iterates over monthly entries. The heart of this is a country formating function that binds a colorbrewer class to the country geojson objects (see below). This works find for the animation portion. The problem is that I am using a custom d3 layer that displays the date of the data currently displayed and acts as a mouseover control to stop the animation and choose a date or to choose a date once the animation is through. It does this by creating an blank svg element that uses the d3.scale() function to round mouse input to an integer that matches the index of the month desired. I've front loaded all the other calculations on load so that the only thing that happens at mouse over is the change of svg class (this is basically the same as Tom Carden's wealth of nations implementation on Bostock's d3 page here). Unfortunately, this still overloads the browser pretty quickly. Is there another way to do this that I'm totally missing? I admit im new to geojson so maybe some way to construct an array of classes with in the class attribute of the geojson object? Thanks a ton of any help.
function foo(local, geojson){
for(var x=0;x<geojson.length;x++){
var n = geojson[x].data.properties.name;
n$(geojson[x].element)
.attr("class", geojson[x].data.formats[local])
.add("svg:title");
}
}
EDIT: I'm adding the full script below.
<meta charset="utf-8">
<script src="scripts/d3.v3.js"></script>
<script src="scripts/polymaps.js"></script>
<script src="scripts/nns.js"></script>
<script>
//Polymaps namespace
var po = org.polymaps;
//Chart dimensions
var margin = {top: 20, right: 20, bottom: 20, left: 20};
var w = 960 - margin.right;
var h = 500 - margin.top - margin.bottom;
// Create the map object, add it to #map div
var map = po.map()
.container(d3.select("#map").append("svg:svg").attr("width", w + margin.left + margin.right).attr("height",h +margin.top + margin.bottom).node())
.center({lat: 28, lon: 0})
.zoom(1.85)
.zoomRange([1.5, 4.5])
.add(po.interact());
// Add the CloudMade image tiles as a base layer…
map.add(po.image()
.url(po.url("http://{S}tile.cloudmade.com"
+ "/1a1b06b230af4efdbb989ea99e9841af" // http://cloudmade.com/register
+ "/20760/256/{Z}/{X}/{Y}.png")
.hosts(["a.", "b.", "c.", ""])));
//Import contribution data
d3.json("assets/contributionsTCC1990-1991.json", function(data){
//find length of json data object and loop over it at interval
var dataLength = Object.keys(data).length;
//Create date key/value array using construtor
function date_array_constructor() {
var dateArray = {};
for(var i = 0; i < dataLength; i++) {
var d = i + 1;
dateArray[d] = data[i].date;
}
return dateArray;
}
var dateArray = date_array_constructor();
// Insert date label/control layer and add SVG elements that take on attributes determined by load function
var labelLayer = d3.select("#map svg").insert("svg:g");
map.add(po.geoJson()
.url("assets/world.json")
.tile(false)
.zoom(3)
.on("load", load));
map.container().setAttribute("class", "Blues");
map.add(po.compass()
.pan("none"));
function find_max(data, dataLength) {
var max = 0;
for(var i in data) {
if(data[i] > max) {
max = data[i] + 1;
}
}
return max;
}
function max_array_constructor(data, dataLength) {
var maxArray = {};
for(var i=0;i<dataLength;i++) {
var d = i+1;
maxArray[d] = find_max(data[i].contributions);
}
return maxArray;
}
var maxArray = max_array_constructor(data, dataLength);
function contribution_array_constructor(data, dataLength, tccName, feature) {
var contributions = {};
//iterate over date entries
for(var i=0;i<dataLength;i++) {
//contribution iterator
contributions[i+1] = 0;
for(x in data[i].contributions){
if(x == tccName) {
contributions[i+1] = data[i].contributions[x];
}
}
}
return contributions;
}
function format_array_constructor(data, dataLength, maxArray, feature) {
var formats = {};
// console.log(feature.data.contributions);
//iterate over date entries
for(var i=0;i<dataLength;i++) {
var percentile = feature.data.contributions[i+1] / maxArray[i+1];
if(percentile != 0){
var v = "q" + ((~~(percentile*7)) + 2) + "-" + 9;
}else{
var v = "countries";
}
formats[i+1] = v;
}
return formats;
}
///////////////////////////////
//load function
///////////////////////////////
function load(e) {
//Bind geojson and json
var geojson = e.features;
console.log(geojson);
geojson.dates = dateArray;
for(var x = 0; x < geojson.length; x++) {
// var tccID = geojson[x].data.id;
var tccName = geojson[x].data.properties.name;
geojson[x].data.contributions = contribution_array_constructor(data, dataLength, tccName, geojson[x]);
geojson[x].data.formats = format_array_constructor(data, dataLength, maxArray, geojson[x]);
}
//Insert date label
var dateLabel = labelLayer.append("text")
.attr("class", "date label")
.attr("text-anchor", "end")
.attr("x", w-670)
.attr("y", h )
.text(dateArray[1]);
//Add interactive overlay for date label
var box = dateLabel.node().getBBox();
var overlay = labelLayer.append("rect")
.attr("class", "overlay")
.attr("x", box.x)
.attr("y", box.y)
.attr("opacity",0)
.attr("width", box.width)
.attr("height", box.height)
.on("mouseover",enable_interaction);
function country_class_constructor(local, geojson){
for(var x=0;x<geojson.length;x++){
var n = geojson[x].data.properties.name;
n$(geojson[x].element)
.attr("class", geojson[x].data.formats[local])
.add("svg:title");
}
}
function foo(local, geojson){
for(var x=0;x<geojson.length;x++){
var n = geojson[x].data.properties.name;
n$(geojson[x].element)
.attr("class", geojson[x].data.formats[local])
.add("svg:title");
}
}
//incrementor function
function incrementor(local, geojson, dateArray) {
setTimeout(function() {
//set date label to current iteration
d3.transition(dateLabel).text(dateArray[local]);
//construct country classes
country_class_constructor(local, geojson);
// console.log(geojson);
}, 500*local);
}
///////////////////////////////
//Increment on load
///////////////////////////////
country_class_constructor(1, geojson)
for(var i=1; i< dataLength; i++) {
//Set incrementer as local variable
var local = i+1;
var timer = incrementor(local, geojson, dateArray);
}
///////////////////////////////
//interaction element
///////////////////////////////
function enable_interaction(){
var dateScale = d3.scale.linear()
.domain([1,Object.keys(dateArray).length])
.range([box.x + 10, box.x + box.width - 10])
.clamp(true);
timer = null;
overlay
.on("mouseover", mouse_over)
.on("mouseout",mouse_out)
.on("mousemove",mouse_move)
.on("touchmove",mouse_move);
function mouse_over() {
dateLabel.classed("active", true);
}
function mouse_out() {
dateLabel.classed("active", false);
}
function mouse_move() {
update_map(dateScale.invert(d3.mouse(this)[0]),data);
// displayYear(dateScale.invert(d3.mouse(this)[0]));
}
function update_map(userInput) {
var date = Math.floor(userInput);
d3.transition(dateLabel).text(dateArray[date]);
// console.log(date);
// country_class_constructor(date, geojson);
foo(date, geojson);
}
}
}
});
</script>
Edit 2: I forgot to add the JSON format. See below for two months of data:
[
{"date":"11/90",
"contributions":{
"Algeria":7,
"Argentina":39,
"Australia":41,
"Austria":967,
"Bangladesh":5,
"Belgium":4,
"Brazil":27,
"Canada":1002,
"Chile":7,
"China":5,
"Colombia":12,
"Czech Republic":6,
"Denmark":374,
"Ecuador":21,
"Fiji":719,
"Finland":992,
"France":525,
"Germany":13,
"Ghana":892,
"Hungary":15,
"India":40,
"Indonesia":5,
"Ireland":814,
"Italy":79,
"Jordan":6,
"Kenya":7,
"Malaysia":15,
"Nepal":851,
"Netherlands":15,
"New Zealand":22,
"Nigeria":2,
"Norway":924,
"Poland":165,
"Republic of the Congo":6,
"Russia":35,
"Senegal":4,
"Serbia":17,
"Spain":63,
"Sweden":738,
"Switzerland":5,
"Turkey":2,
"United Kingdom":769,
"United States":33,
"Uruguay":10,
"Venezuela":23,
"Zambia":6
}
},
{"date":"12/90",
"contributions":{
"Algeria":7,
"Argentina":39,
"Australia":41,
"Austria":967,
"Bangladesh":5,
"Belgium":4,
"Brazil":27,
"Canada":1002,
"Chile":7,
"China":5,
"Colombia":12,
"Czech Republic":6,
"Denmark":374,
"Ecuador":21,
"Fiji":719,
"Finland":992,
"France":525,
"Germany":13,
"Ghana":892,
"Hungary":15,
"India":40,
"Indonesia":5,
"Ireland":814,
"Italy":79,
"Jordan":6,
"Kenya":7,
"Malaysia":15,
"Nepal":851,
"Netherlands":15,
"New Zealand":22,
"Nigeria":2,
"Norway":924,
"Poland":165,
"Republic of the Congo":6,
"Russia":35,
"Senegal":4,
"Serbia":17,
"Spain":63,
"Sweden":738,
"Switzerland":5,
"Turkey":2,
"United Kingdom":769,
"United States":33,
"Uruguay":10,
"Venezuela":23,
"Zambia":6
}
}
]
After hours of debugging, it turns out that the nns.js library was causing me problems. Each iteration of the animation was creating a new set of DOM objects which started to max out the browser at 25,000. The solution was to use nss to create the initial state and then using the following function to change the class of each svg element.
function country_class_constructor(local, geojson){
for(var x=0;x<geojson.length;x++){
var n = geojson[x].data.properties.name;
element = document.getElementById(n);
element.className["animVal"] = geojson[x].data.formats[local];
element.className["baseVal"] = geojson[x].data.formats[local];
}
I am using Google Maps Distance Matrix and what I need is two different distances,
at the moment I have the following:-
var start = arrObjLatLngs[0];
var end = arrObjLatLngs[arrObjLatLngs.length - 1];
var base = new google.maps.LatLng(52.781048888889, -1.2110222222222546);
var service = new google.maps.DistanceMatrixService();
service.getDistanceMatrix(
{
origins: [base],
destinations: [start, end],
travelMode: google.maps.TravelMode.DRIVING,
unitSystem: google.maps.DirectionsUnitSystem.METRIC,
avoidHighways: false,
avoidTolls: false
}, callback);
function callback(response, status) {
if (status == google.maps.DistanceMatrixStatus.OK) {
var origins = response.originAddresses;
var destinations = response.destinationAddresses;
for (var i = 0; i < origins.length; i++) {
var results = response.rows[i].elements;
for (var j = 0; j < results.length; j++) {
var element = results[j];
var distance = Math.round(parseFloat(element.distance.text));
alert(distance);
var duration = element.duration.text;
var from = origins[i];
var to = destinations[j];
}
}
}
}
When I alert($distance); I get two responses, e.g. 15 and 10
What I need is two seperate values, i.e. if I alert($runinPickup); I get 15 , if I alert alert($runinDestination); I get 10.
I thought they were in an array so I have tried alert(distance[0]) but this comes back as undefined.
Do I have to do two seperate getDistanceMatrix requests or is there a way to seperate the two values?
I want to know how to show infowindow on polyline in using Google Maps Api V3? and to appear in the middle of the polyline ?!
Firstly you will need to calculate the middle/center of the polyline. This has been discussed and answered here;
https://stackoverflow.com/a/9090409/787921
Then you will have to open the infowindow;
var infowindow = new google.maps.InfoWindow({
content: "infowindow text content"});
infowindow.setPosition(midLatLng);
infowindow.open(map);
find the middle point and set your custom view .
func showPath(polyStr :String){
polyline?.map = nil
mapView1.reloadInputViews()
pathDraw = GMSPath(fromEncodedPath: polyStr)!
polyline = GMSPolyline(path: pathDraw)
polyline?.strokeWidth = 4.0
polyline?.strokeColor = UIColor.init(red: 247/255.0, green: 55/255.0, blue: 76/255.0, alpha: 1.0)
polyline?.map = mapView1
let poinsCount = pathDraw.count()
let midpoint = pathDraw.coordinate(at: poinsCount)
DispatchQueue.main.async
{
self.addMarkerPin(corrdinate: midCordinate, distance: "10 min")
}
}
func addMarkerPin(corrdinate:CLLocationCoordinate2D, distance: String)
{
let marker = GMSMarker()
marker.position = corrdinate
PathTimeView = PathInfoView.loadFromNib() //here i am load Xib file, you can use your custom view
let DynamicView=PathTimeView
DynamicView.timelbl.text = distance
UIGraphicsBeginImageContextWithOptions(DynamicView.frame.size, false, UIScreen.main.scale)
DynamicView.layer.render(in: UIGraphicsGetCurrentContext()!)
let imageConverted: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
marker.icon = imageConverted
marker.map = self.mapView1
marker.infoWindowAnchor = CGPoint(x: -1900 , y: -2000)
}
First you should got center/middle of polyline and this what works for me
private fun centerPos(points: MutableList<LatLng>): LatLng {
val middleDistance = SphericalUtil.computeLength(points).div(2)
return extrapolate(points, points.first(), middleDistance.toFloat()) ?: points[0]
}
private fun extrapolate(path: List<LatLng>, origin: LatLng, distance: Float): LatLng? {
var extrapolated: LatLng? = null
if (!PolyUtil.isLocationOnPath(
origin,
path,
false,
1.0
)
) { // If the location is not on path non geodesic, 1 meter tolerance
return null
}
var accDistance = 0f
var foundStart = false
val segment: MutableList<LatLng> = ArrayList()
for (i in 0 until path.size - 1) {
val segmentStart = path[i]
val segmentEnd = path[i + 1]
segment.clear()
segment.add(segmentStart)
segment.add(segmentEnd)
var currentDistance = 0.0
if (!foundStart) {
if (PolyUtil.isLocationOnPath(origin, segment, false, 1.0)) {
foundStart = true
currentDistance = SphericalUtil.computeDistanceBetween(origin, segmentEnd)
if (currentDistance > distance) {
val heading = SphericalUtil.computeHeading(origin, segmentEnd)
extrapolated = SphericalUtil.computeOffset(
origin,
(distance - accDistance).toDouble(),
heading
)
break
}
}
} else {
currentDistance = SphericalUtil.computeDistanceBetween(segmentStart, segmentEnd)
if (currentDistance + accDistance > distance) {
val heading = SphericalUtil.computeHeading(segmentStart, segmentEnd)
extrapolated = SphericalUtil.computeOffset(
segmentStart,
(distance - accDistance).toDouble(),
heading
)
break
}
}
accDistance += currentDistance.toFloat()
}
return extrapolated
}
then You can add infoWindow with normal way with your platform at it is differ from each platform