<\/p>\n"},{"acf_fc_layout":"content","content":"
Take a look at these two attribute rules, the first one calculates the distance of the nearest point and the second one calculates a uniqueName every time the Name field is updated by appending a guid.<\/p>\n"},{"acf_fc_layout":"content","content":"
\/\/get the feature geometry<\/span>\r\nvar<\/span> g1 = Geometry($feature)\r\n\/\/get the object id<\/span>\r\nvar<\/span> oid = $feature.objectid\r\n\/\/get the entire class <\/span>\r\nvar<\/span> fsPointClass = FeatureSetByName($datastore, \"pointClass\"<\/span>, ['objectid'<\/span>], true<\/span>) \r\n\/\/filter all features except this feature (we don't want the current feature to be returned)<\/span>\r\nvar<\/span> allPointsExceptThis = Filter(fsPointClass , \"objectid <> @oid\"<\/span>)\r\n\/\/return if no rows <\/span>\r\nif<\/span> (count(allPointsExceptThis) == 0<\/span>) return<\/span> 0<\/span>;\r\n\/\/calculate the minimum distance<\/span>\r\nvar<\/span> distances = [];\r\nvar<\/span> c = 0<\/span>;\r\nfor<\/span> (var<\/span> f in<\/span> allPointsExceptThis) {\r\n var<\/span> d = Distance(g1, Geometry(f), 'feet'<\/span>)\r\n distances[c++] = d;\r\n}\r\n\/\/return <\/span>\r\nreturn<\/span> min(distances)\r\n<\/code><\/pre>\n"},{"acf_fc_layout":"content","content":"return<\/span> $feature.Name + Guid() \r\n<\/code><\/pre>\n"},{"acf_fc_layout":"content","content":"The scripts are executed regardless of any edit and that might not be desirable. Ideally, we want the distance to be calculated only when the feature geometry is updated (e.g. a feature is moved) and for the uniqueName to get calculated with a new guid only when the Name field is updated.<\/p>\n
Meet $originalFeature<\/strong>.<\/p>\n"},{"acf_fc_layout":"content","content":"What is the $originalFeature?<\/h1>\n
The $originalFeature<\/strong> is a new Arcade global that presents the state of the feature before the edit giving the script author flexibility to compare the current values $feature<\/strong> with the original values of the feature.<\/p>\nLet us rewrite the distance attribute rule so that we only execute the script if the geometry has changed.<\/p>\n"},{"acf_fc_layout":"content","content":"
\/\/check if the geometry has changed or not, if it didn't simply return<\/span>\r\nif<\/span> ( Equals(Geometry($feature), Geometry($originalFeature))) return<\/span> $feature.distance\r\n\r\n\/\/get the feature geometry<\/span>\r\nvar<\/span> g1 = Geometry($feature)\r\n\/\/get the object id<\/span>\r\nvar<\/span> oid = $feature.objectid\r\n\/\/get the entire class <\/span>\r\nvar<\/span> fsPointClass = FeatureSetByName($datastore, \"pointClass\"<\/span>, ['objectid'<\/span>], true<\/span>) \r\n\/\/filter all features except this feature (we don't want the current feature to be returned)<\/span>\r\nvar<\/span> allPointsExceptThis = Filter(fsPointClass , \"objectid <> @oid\"<\/span>)\r\n\/\/return if no rows <\/span>\r\nif<\/span> (count(allPointsExceptThis) == 0<\/span>) return<\/span> 0<\/span>;\r\n\/\/calculate the minimum distance<\/span>\r\nvar<\/span> distances = [];\r\nvar<\/span> c = 0<\/span>;\r\nfor<\/span> (var<\/span> f in<\/span> allPointsExceptThis) {\r\n var<\/span> d = Distance(g1, Geometry(f), 'feet'<\/span>)\r\n distances[c++] = d;\r\n}\r\n\/\/return <\/span>\r\nreturn<\/span> min(distances)\r\n<\/code><\/pre>\n"},{"acf_fc_layout":"content","content":"We can do the same for the UniqueName attribute rule by checking if the Name field has been updated or not and return the current unqiueName.<\/p>\n"},{"acf_fc_layout":"content","content":"
\/\/if the name didn't change don't generate a new uniquename guid<\/span>\r\nif<\/span> ($originalFeature.Name == $feature.Name) return<\/span> $feature.uniqueName\r\nreturn<\/span> $feature.Name + Guid() \r\n<\/code><\/pre>\n
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