topic Re: How to select the date of most recent record in featurelayer to automatically configure time slider in ArcGIS JavaScript Maps SDK Questions

How to select the date of most recent record in featurelayer to automatically configure time slider

EmilyGoldsmith — Fri, 17 May 2024 10:39:56 GMT

Hello,

I'm in a bit of an tricky situation where a layer with automatic refreshes in one of our ArcGIS JavaScript apps has been configured to have an incorrect, static time extent in its timeinfo - with us being unable to make changes to said layer currently. This has led our time slider to have the wrong time extent info in our ArcGIS JavaScript 4.27 app.

A quick fix I came up with was to overwrite the time extent when setting up the timeslider, which has fixed the time extent issue temporarily - see here:

//create time slider for layer const timeSlider = new TimeSlider({ container: "timeSlider", view: view, timeVisible: true, // show the time stamps on the timeslider loop: true, fullTimeExtent: { // entire extent of the timeSlider start: new Date(2003, 5, 19), end: new Date(2024, 5, 16) }, }); view.whenLayerView(layer).then((lv) => {timeSlider.fullTimeExtent.expandTo("weeks"); timeSlider.stops = {interval: layer.timeInfo.interval}; }); view.ui.add(timeSlider, "bottom-left");

However, I would like to have a way to automatically get the most recent date from the feature layer's time field 'DATE_CREATED' and have this set to be the 'end' value in TimeSlider()'s 'fullTimeExtent.'

Does anybody know if this is possible?

Thank you.

Re: How to select the date of most recent record in featurelayer to automatically configure time slider

AngelaSchirck — Fri, 17 May 2024 12:43:44 GMT

Assuming you referenced the layer and can query its features you can try something like this:

// Assuming your layer variable holds a reference to the layer
layer.queryFeatures().then((featureSet) => {
const endDateAttribute = featureSet.features[0].attributes.DATE_CREATED;

// Create a Date object from the attribute value
const endDate = new Date(endDateAttribute);

// Create a time slider with the dynamic end date
const timeSlider = new TimeSlider({
container: "timeSlider", // ID of the HTML element where the time slider will be placed
view: view, // MapView or SceneView instance
timeVisible: true, // Show the time stamps on the time slider
loop: true, // Enable looping of time animation
fullTimeExtent: { // Entire extent of the time slider
start: new Date(2003, 5, 19), // Start date
end: endDate // End date based on the feature attribute
}
});

// When the layer view is ready, configure the time slider
view.whenLayerView(layer).then((lv) => {
timeSlider.fullTimeExtent.expandTo("weeks"); // Expand the time extent to weeks
timeSlider.stops = { interval: layer.timeInfo.interval }; // Set stops based on the layer's time interval
});

// Add the time slider to the view's UI (bottom-left position)
view.ui.add(timeSlider, "bottom-left");
});

Re: How to select the date of most recent record in featurelayer to automatically configure time slider

EmilyGoldsmith — Fri, 17 May 2024 15:03:48 GMT

Hello,

Many thanks for your help.

I gave your code a go and it was perfect in querying the earliest date in the dataset (which is at the top of the layer's table) but not the latest.

I gave finding the length of the feature layer a go and then putting that as the feature to be queried, however this just returned an error, which occurred whenever featureset.features[x] was over 999.

//Find the length of the entire feature layer layer.queryFeatureCount().then(function(numFeatures){ // prints the total count to the console console.log(numFeatures); //49880 layer.queryFeatures().then((featureSet) => {const endDateAttribute = featureSet.features[numFeatures].attributes.DATE_CREATED; // Create a Date object from the attribute value const enddate = new Date(endDateAttribute); console.log("enddate" , {enddate}); //create time slider for layer const timeSlider = new TimeSlider({ container: "timeSlider", view: view, timeVisible: true, // show the time stamps on the timeslider loop: true, fullTimeExtent: { // entire extent of the timeSlider start: new Date(2003, 5, 18), end: enddate} }); view.whenLayerView(layer).then((lv) => {timeSlider.fullTimeExtent.expandTo("weeks"); timeSlider.stops = {interval: layer.timeInfo.interval}; }); view.ui.add(timeSlider, "bottom-left"); }); });

I'm a bit unsure of where to go from here. Do you think I have to set a 'wait until layer loaded' function prior to ensure the query can select the latest record?

Re: How to select the date of most recent record in featurelayer to automatically configure time slider

EmilyGoldsmith — Mon, 20 May 2024 10:38:54 GMT

Hi, just to give an update on this but I think I figured out how to do it by adding a statistical query to your code.

Essentially, the following queries by the 'maximum' date in the FeatureLayer and then selects this date to be the timeslider's new 'enddate.'

//Get the 'maximum' date (most recent) const query = new Query(); query.outStatistics = [{ onStatisticField: "DATE_CREATED", outStatisticFieldName: "MAX_DATE", statisticType: "max" }]; //Query by the maxmimum date query set above layer.queryFeatures(query).then((featureSet) => { const endDateAttribute = featureSet.features[0].attributes.MAX_DATE; console.log("Most Recent Date", endDateAttribute); //Print this date // Create a Date object from the attribute value const enddate = new Date(endDateAttribute); console.log("enddate" , {enddate}); //Ensure date converted successfully //create time slider for layer const timeSlider = new TimeSlider({ container: "timeSlider", view: view, timeVisible: true, // show the time stamps on the timeslider loop: true, fullTimeExtent: { // entire extent of the timeSlider start: new Date(2003, 5, 19), end: enddate} }); view.whenLayerView(layer).then((lv) => {timeSlider.fullTimeExtent.expandTo("weeks"); timeSlider.stops = {interval: layer.timeInfo.interval}; }); view.ui.add(timeSlider, "bottom-left"); });

A solution to why the code in my previous message didn't work is because QueryTasks have a limit of 1000 (see here.) Reading this post, I was concerned I might have had to query by the maximum OBJECTID but this solution seems to work surprisingly well for now. Though I will keep an eye on it to ensure that it functions as it should.

Thanks again for your help!

Re: How to select the date of most recent record in featurelayer to automatically configure time slider

AngelaSchirck — Mon, 20 May 2024 11:35:55 GMT

Great, glad you got it to work!