ConvexHullAggregate (geography Data Type)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
SQL database in Microsoft Fabric
Returns a convex hull for a given set of geography objects.
Syntax
ConvexHullAggregate ( geography_operand )
Arguments
geography_operand
Is a geography type table column that represents a set of geography objects.
Return Types
SQL Server return type: geography
Exception
Throws a FormatException when there are input values that are not valid. See STIsValid (geography Data Type)
Remarks
Method returns null when the input is empty or the input has different SRIDs. See Spatial Reference Identifiers (SRIDs)
Method ignores null inputs.
Note
Method returns null if all inputted values are null.
Examples
The following example returns a convex hull of the set of geography objects.
USE AdventureWorks2022
GO
SELECT geography::ConvexHullAggregate(SpatialLocation).ToString() AS SpatialLocation
FROM Person.Address
WHERE City LIKE ('Bothell')