Data Expression to show Value changed each Year

RosemaryHatch2013 — Thu, 08 Jun 2023 15:32:45 GMT

Hello!

I'm trying to show a line graph in a dashboard of the CHANGE in a value by year. I was able to get an arcade expression to create a featureset that shows the change by year, however I need to add the ability to filter that feature set by the 'UNIT_NAME'. So ideally, there would be a row for each year and unit combination, with the value being the change from the previous year for that unit.

Any help (I'm thinking either a nested dictionary, or something similar?) would be appreciated!

// Write an expression that returns a FeatureSet. // Documentation: https://arcg.is/3c419TD // Samples: https://arcg.is/38SEWWz var portal = Portal('https://arcgis.com'); //Feature Set from hosted var fs = FeatureSetByPortalItem( portal, 'examplelyr', 0, [ 'Year_Collected', 'UNIT_NAME', 'LAST_INFESTED_AREA' ], false ); //Group by Year Collected (and Ideally Unit Name) var sumfs = GroupBy( fs, ['Year_Collected', 'UNIT_NAME'], [{ name:'TotalInfestedArea', expression:'LAST_INFESTED_AREA', statistic:'SUM' }] ); //Create a new, ordered layer var sumfsOrder = Orderby(sumfs, 'Year_Collected') //Create an empty dictionary to hold values output by above groupby function var dictYearCount = {} //Create a dictionary to hold the change in values (AcresChanged) var dictYearChange = { 'fields': [ {name: "Year", type: "esriFieldTypeString" }, {name: "Unit", type: "esriFieldTypeString" }, {name: "AcresChanged", type: "esriFieldTypeDouble" } ], geometryType: "", features: [], } //Add Key/Value pairs to dictYearCount Dictionary //Key is Year Collected, Value is total infested area for (var f in sumfsOrder){ var yearKey = Text(f.Year_Collected) var yearValue = f['TotalInfestedArea'] //Somewhere in here add ability for a second key, or dictionary, or something to keep Unit as a variable dictYearCount[yearKey] = yearValue } //For each row in the grouping, create a variable for the current year // and the previous year value for (var t in sumfsOrder) { if (HasKey(dictYearCount, Text(t.Year_Collected-1)) == true) { var previousYearCount = dictYearCount[Text(t.Year_Collected-1)] var currentYearCount = dictYearCount[Text(t.Year_Collected)] //Subtract the two values var Diff = currentYearCount - previousYearCount //Add the new differenct to the Change Dictionary Push( dictYearChange['features'], { attributes: { Year: Text(t.Year_Collected), AcresChanged: Diff } } ) } //If no previous value (ie first year) leave value field empty else { Push( dictYearChange['features'], { attributes: { Year: Text(t.Year_Collected), AcresChanged: "" } } ) } } Console(dictYearChange) var YearChange = FeatureSet(Text(dictYearChange)) return YearChange

topic Data Expression to show Value changed each Year in ArcGIS Dashboards Questions

Data Expression to show Value changed each Year