topic Re: Arcade expression for Min, Max, Avg and Count in ArcGIS Online Questions

Arcade expression for Min, Max, Avg and Count

User1RECS — Thu, 19 May 2022 12:03:47 GMT

I am working on the typology of urban blocks. Each block contains a number of buildings, each of which has an area and a height.
I would like to calculate the maximum, minimum, average and median area and height in each block on arcade. Can you help me please?

Re: Arcade expression for Min, Max, Avg and Count

JohannesLindner — Thu, 19 May 2022 12:33:04 GMT

You need a table with a block id, building height, and building area
You need one of the FeatureSetBy*() functions to load your building data
You need the GroupBy() function to group your building data by block id.

For the functions, look here:

https://developers.arcgis.com/arcade/function-reference/data_functions/#featuresetbyid

https://developers.arcgis.com/arcade/function-reference/data_functions/#groupby

As an example, you can use the following code in the Playground | ArcGIS Arcade | ArcGIS Developer

var fs_buildings = { "geometryType": "", "fields": [ {"name": "BlockID", "type": "esriFieldTypeInteger"}, {"name": "BuildingID", "type": "esriFieldTypeInteger"}, {"name": "BuildingHeight", "type": "esriFieldTypeDouble"}, {"name": "BuildingArea", "type": "esriFieldTypeDouble"} ], "features": [ {"attributes": {"BlockID": 1, "BuildingID": 1, "BuildingHeight": 10., "BuildingArea": 300.}}, {"attributes": {"BlockID": 1, "BuildingID": 2, "BuildingHeight": 30., "BuildingArea": 500.}}, {"attributes": {"BlockID": 1, "BuildingID": 3, "BuildingHeight": 15., "BuildingArea": 250.}}, {"attributes": {"BlockID": 2, "BuildingID": 4, "BuildingHeight": 16., "BuildingArea": 400.}}, {"attributes": {"BlockID": 2, "BuildingID": 5, "BuildingHeight": 10., "BuildingArea": 300.}}, {"attributes": {"BlockID": 3, "BuildingID": 6, "BuildingHeight": 10., "BuildingArea": 300.}} ] } fs_buildings = FeatureSet(Text(fs_buildings)) //return fs_buildings // actually use one of the FeatureSetBy*() functions: //var p = Portal(...) //var fs_buildings = FeatureSetByPortalItem(p, item, layer, ["BlockID", "BuildingID", "BuildingHeight", "BuildingArea"], false) var statistics = [ {"name": "Count", "expression": "BuildingID", "statistic": "COUNT"}, {"name": "HeightMax", "expression": "BuildingHeight", "statistic": "MAX"}, {"name": "HeightMin", "expression": "BuildingHeight", "statistic": "MIN"}, {"name": "HeightMean", "expression": "BuildingHeight", "statistic": "AVG"}, {"name": "AreaMax", "expression": "BuildingArea", "statistic": "MAX"}, {"name": "AreaMin", "expression": "BuildingArea", "statistic": "MIN"}, {"name": "AreaMean", "expression": "BuildingArea", "statistic": "AVG"}, ] var fs_grouped_buildings = GroupBy(fs_buildings, "BlockID", statistics) return fs_grouped_buildings

Re: Arcade expression for Min, Max, Avg and Count

User1RECS — Thu, 19 May 2022 13:13:44 GMT

Thank you very much for your quick response

in fact I already have a table with the BlockID, the ID of the buildings, the area and the height of each building. and I would like to calculate from this table.

Re: Arcade expression for Min, Max, Avg and Count

User1RECS — Thu, 19 May 2022 23:37:55 GMT

could you, please, tell me how to calculate each statistic by adding a new field on my buildings table and calculating the field?

Re: Arcade expression for Min, Max, Avg and Count

JohannesLindner — Fri, 20 May 2022 04:48:42 GMT

If you want to do this in the CalculateField tool, you can use this expression, modified for each statistic:

// load the whole feature class var fs_buildings = FeatureSetByName($datastore, "BuildingFC", ["BlockID", "BuildingID", "BuildingHeight", "BuildingArea"], false) // only select rows with the current feature's BlockID var id = $feature.BlockID var fs_buildings_block = Filter(fs_buildings, "BlockID = @ID") // edit this line for each statistic and field return Min(fs_buildings_block, "BuildingHeight")

Re: Arcade expression for Min, Max, Avg and Count

User1RECS — Fri, 20 May 2022 10:34:28 GMT

IT work...Thank you very much !!!!