topic Re: Getting Statistics on a field in ArcGIS Pro SDK Questions

Getting Statistics on a field

BrianBulla — Fri, 24 Nov 2017 13:48:23 GMT

In ArcObjects I would use Geodatabase.IDataStatistics to get stats on a field. Does anyone know if an equivalent exists in ArcPro SDK??

Thanks,

Re: Getting Statistics on a field

ColinZwicker — Mon, 27 Nov 2017 22:11:09 GMT

Brian,

ArcGIS Pro Core.Data has not exposed this functionality yet. We will look to do so in a future release.

Do you utilize the simple stats (count, min\max etc) or standard deviation?

Thanks,

Colin

Re: Getting Statistics on a field

BrianBulla — Tue, 28 Nov 2017 20:21:57 GMT

Hi Colin,

Just simple stats is all I am looking for.

Thanks!

Re: Getting Statistics on a field

GKmieliauskas — Wed, 29 Nov 2017 13:39:35 GMT

Hi Colin,

We are using UniqueValues, min, max. Please accelerate exposing of this functionality

Re: Getting Statistics on a field

Anonymous User — Thu, 12 Jul 2018 11:22:20 GMT

Hi Colin any word on when this might be exposed? Could do with an easy way of getting unique values from a field.

Re: Getting Statistics on a field

ColinZwicker — Fri, 13 Jul 2018 16:49:17 GMT

Good timing

With the release of 2.2 check out:

ProConcepts Geodatabase · Esri/arcgis-pro-sdk Wiki · GitHub

Edit: totally missed your unique value statement, let me check with the team.

Thanks,

Colin

Re: Getting Statistics on a field

Anonymous User — Tue, 17 Jul 2018 15:56:32 GMT

Thanks Colin, yes please confirm if unique vals can be retrieved

Cheers

Re: Getting Statistics on a field

RichRuh — Mon, 23 Jul 2018 17:49:30 GMT

Hi Luke,

Yes, it is possible to get the unique values of a field, but the way to do so isn't obvious.

As Colin pointed out, the key is to use the Table.CalculateStatistics() routine. This will allow you to generate statistics on one or more fields and includes the ability to execute a group by on these statistics. To get the unique values, you execute this code, passing in a "dummy" statistic to calculate.

In the example below, I build a list of unique values for the SUB_REGION field of a States table.

// Get field for Region

Field regionField = featureClassDefinition.GetFields().First(x => x.Name.Equals("SUB_REGION"));

// Create a "fake" StatisticsDescription object

StatisticsDescription statisticsDescription = new StatisticsDescription(regionField, new List<StatisticsFunction>() { StatisticsFunction.Count });

// Create a TableStatisticsDescription that will return unique Region values (and a

// count of how many rows have that value)

TableStatisticsDescription tableStatisticsDescription = new TableStatisticsDescription(new List<StatisticsDescription>() { statisticsDescription });

tableStatisticsDescription.GroupBy = new List<Field>(){ regionField };

// Generate the statistics (and list of unique values)

IReadOnlyList<TableStatisticsResult> results = statesFeatureClass.CalculateStatistics(tableStatisticsDescription);

// Table.CalculateStatistics() returns one TableStatisticsResult object for each unique

// GroupBy tuple.
// If you pass one field into the TableStatisticsDescription.GroupBy object, you'll get

// one TableStatisticsResult object for each unique value of that field

foreach(TableStatisticsResult result in results)
{
// TableStatisticsResult.GroupBy returns one KeyValuePair<Field,object> for each field

// in the TableStatisticsDescription.GroupBy list
// If you only pass one field into that list, we only get one

// KeyValuePair<Field,object>

KeyValuePair<Field, object> groupByPair = result.GroupBy.First();

// groupByPair.Field is the Field you passed into TableStatisticsDescription.GroupBy
// groupByPair.Value is a unique value of that field

string myFieldValue = (string) groupByPair.Value;
Console.WriteLine(myFieldValue);
}

We'll take a look at providing a more obvious way this to do in a future version of ArcGIS Pro.

Let me know if this helps,

--Rich

Re: Getting Statistics on a field

DaveFullerton — Fri, 26 May 2023 18:05:16 GMT

Did you ever provide a more obvious way to do this in the API, Rich? I am running into some issues with this not working so well, for example, with type CIMXYEventDataConnection and when CIMSqlQueryDataConnection becomes CIMRelQueryTableDataConnection via joining to a local table (it does work with a join when the data are all in the file geodatabase).

Re: Getting Statistics on a field

DaveFullerton — Thu, 21 Sep 2023 16:41:57 GMT

@RichRuh @KoryKramer @ColinZwicker

Repeating this question and tagging you guys in case you didn't see it before.

Did Esri ever provide a more obvious way to do this in the API, Rich? I am running into some issues with this not working so well, for example, with type CIMXYEventDataConnection and when CIMSqlQueryDataConnection becomes CIMRelQueryTableDataConnection via joining to a local table (it does work with a join when the data are all in the file geodatabase).

Re: Getting Statistics on a field

RichRuh — Thu, 21 Sep 2023 17:16:58 GMT

@DaveFullerton No changes here.

I'm not familiar with the CIM*** classes, but if you have a reproducible case you can share with tech support, they can send it to us for investigation.

--Rich

Re: Getting Statistics on a field

DaveFullerton — Thu, 21 Sep 2023 18:23:01 GMT

Thanks @RichRuh . It has been a while since I looked at this (was interrupted by other priorities). I will probably contact tech support as you suggest.

Re: Getting Statistics on a field

DaveFullerton — Wed, 06 Dec 2023 21:48:24 GMT

I have looked this over more carefully now and have worked around this as much as I think I need to. I am just using it to get a unique list of values, so in case anyone else is trying to do that or anyone has any further insights that they would be able to share, this is what I have concluded so far:

It is not surprising that I was unable to use Rich Ruh’s code snippet with XY Event Layers since in the Pro GUI you cannot run the “Summarize Statistics'' tool on fields in these layers. You get an error message about there being no OID field.

You can run the “Summarize Statistics” tool on a field in a layer with a joined table. However, for using the code snippet, FeatureClass.GetDefinition() and Table.GetDefinition() are expected to throw an exception if called when there is a table join. This can be found in the API documentation here:

https://pro.arcgis.com/en/pro-app/latest/3.2/api-reference/topic7713.html

https://pro.arcgis.com/en/pro-app/latest/sdk/api-reference/topic7014.html

So it seems that this is a known limitation and there is a reasonable sounding explanation provided for it, but since “Summarize Statistics” can be done through the Pro GUI when there is a joined table, it is surprising that we cannot do this using the SDK too.

To be clear, in my code, I start with a BasicFeatureLayer, get a Table from it with GetTable() and then use Table.GetDefinition().

The thing that initially confused me was that Table.GetDefinition() didn’t throw an exception when the data source of the BasicFeatureLayer was a FGDB feature class and it was joined with a table within that same FGDB.

For now, I want to allow users the opportunity to use my addin in the above mentioned FGDB joined table case (or any case that Table.GetDefinition() happens to work), so I decided to do something like this at the beginning when getting the TableDefinition:

Table table = myBasicFeatureLayer.GetTable(); TableDefinition tableDefinition; try { tableDefinition = table.GetDefinition(); } catch (Exception e) { if (table.IsJoinedTable()) { ArcGIS.Desktop.Framework.Dialogs.MessageBox.Show("Won't work with join…"); } else { MessageBox.Show("Please contact GIS staff…" + e.ToString()); } return; }