Arcade Data Expression - Create dictionary from Geometry

SteveRichards1 — Tue, 22 Mar 2022 22:23:30 GMT

Hello All,

I am new to Arcade Data Expressions and I would like to return a Feature Set that contains all of the "Fire Numbers" and the corresponding "District" (polygon) that it falls within. I started off with the code in the below link and tried to modify it a little to make it work for my situation. Mainly, I added an additional sub "for-loop" to iterate through the points and for each point determine the district it falls within and put that into an array and finally a dictionary.

https://github.com/Esri/arcade-expressions/blob/master/dashboard_data/SpatialAggregation.md

The Data Expression will be used within a Category Selector so I can filter the fire numbers out that only fall within a specific district (a district selector would filter out this data expression feature set to show only relevant fire numbers )

I am not able to get this to work and I am unsure what to try next. Can anyone potentially guide me in the right direction or maybe show another approach? Any help is very much appreciated!

// Portal var portal = Portal('https://governmentofbc.maps.arcgis.com/'); // Create FeatureSet for polygons var poly_fs = FeatureSetByPortalItem( portal, '5ccd439dd835451aa304468ebdce0427', 58, [ 'ORG_UNIT' ], true ); // Create Featureset for points var pt_fs = FeatureSetByPortalItem( portal, '397a1defe7f04c2b8ef6511f6c087dbf', 0, [ 'FIRE_NUMBER' ], true ); // Create empty feature array and feat object for output var features = []; var feat; // Iterate over fire points for (var pt in pt_fs) { // Iterate over districts for (var poly in poly_fs) { // Filter points by polygon var pts = Contains(poly, pt); // Create feature with aggregated values feat = { 'attributes': { 'district': poly['ORG_UNIT'], 'fire': pt['FIRE_NUMBER'] } }; // Push feature into array Push(features, feat); }; }; // Create dict for output FeatureSet var out_dict = { 'fields': [ {'name': 'district', 'alias': 'Districts', 'type': 'esriFieldTypeString'}, {'name': 'fire', 'alias': 'Fire Number', 'type': 'esriFieldTypeString'} ], 'geometryType': '', 'features': features }; // Convert dictionary to feature set. return FeatureSet(Text(out_dict));

Re: Arcade Data Expression - Create dictionary from Geometry

SteveRichards1 — Tue, 22 Mar 2022 22:58:28 GMT

OK. I was able to get it to work finally. The issue was that I was not passing in a FeatureSet for the inside geometry (points) as part of the Contains function, which caused an error. I looped through the returned points after creating the list of points that intersected each polygon. Working code below.

// Create empty feature array and feat object for output var features = []; var feat; // Iterate over districts for (var poly in poly_fs) { // Filter points by polygon var pts = Contains(poly, pt_fs); for (var pt in pts) { // Create feature with aggregated values feat = { 'attributes': { 'district': poly['ORG_UNIT'], 'fire': pt['FIRE_NUMBER'] } }; // Push feature into array Push(features, feat); }; }; // Create dict for output FeatureSet var out_dict = { 'fields': [ {'name': 'district', 'alias': 'Districts', 'type': 'esriFieldTypeString'}, {'name': 'fire', 'alias': 'Fire Number', 'type': 'esriFieldTypeString'} ], 'geometryType': '', 'features': features }; // Convert dictionary to feature set. return FeatureSet(Text(out_dict));

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Arcade Data Expression - Create dictionary from Geometry

Re: Arcade Data Expression - Create dictionary from Geometry