This sample demonstrates how to query a feature table to get aggregated statistics back for a specific field.
How it works
Select the appropriate switch to filter features by attributes and/or within the current extent. Click the button to see basic statistics displayed for world cities.
An AGSServiceFeatureTable is created with a URL to the REST endpoint of a feature service. AGSStatisticsQueryParameters are created, and several AGSStatisticDefinition objects are created and added to the parameters. These definitions defines the various statistics that we would like to compute, such as average, minimum and maximum of a given field. When the button is clicked, queryStatistics is executed on the AGSServiceFeatureTable. Depending on the state of two switches, additional paramters are set. This process runs asynchronously, and once completed, returns AGSStatisticsQueryResult, which contains key/value pairs as the result.