Implementation of Geospatial Reduce Methods

[Gopalverma062]

Summary

Implements the Reduce() function for both geometry and geography spatial types using the Douglas-Peucker algorithm to simplify geometries.

Changes

• Added sys.Reduce(tolerance, geometry) function
• Added sys.Reduce(tolerance, geography) function
• Added sys.Reduce_helper() for geography meter-to-degree conversion
• Added sys.geography_simplify_internal() wrapper for PostGIS
• Added upgrade script for spatial_types--5.5.0--5.6.0.sql
• Added comprehensive test cases

TSQL Compatibility

• Matches TSQL behavior for supported types
• Handles NULL, empty, and invalid geometries correctly
• Preserves SRID
• Returns original geometry when simplification produces invalid result

Test Coverage

• Geometry: LINESTRING, POLYGON, POINT with various tolerances (0, 0.1, 0.5, 1.0, 2.0, 10, 50)
• Geography: LINESTRING, POLYGON, POINT with meter-based tolerances (0, 10, 100, 1000, 10000, 100000)
• Edge cases: NULL, empty, invalid geometry, negative tolerance
• SQL patterns: SELECT, WHERE, CTE, Views, GROUP BY, ORDER BY
• Table column operations

Testing Done

• All existing tests pass
• New test cases pass
• Compared results with SQL Server - matches