Query Spatial with PostGIS

Overview

Querying spatial data effectively starts with understanding how geography is modeled, indexed, and analyzed inside a relational database. In this hands-on course, you’ll move beyond basic SQL by learning how to query geospatial data using PostGIS, PostgreSQL’s spatial extension. You’ll begin by working with core geometry types and spatial reference systems, building a foundation for how location data is stored and interpreted. From there, you’ll write spatial queries that perform distance calculations, proximity searches, and spatial joins to answer real-world questions. As you progress, you’ll explore spatial indexing and query patterns that improve performance and reliability as datasets grow. By the end of the course, you’ll produce reusable spatial SQL queries and analysis patterns that support practical use cases in areas such as logistics, urban planning, and geospatial data engineering—equipping you to work confidently with location-based data in production environments.

Syllabus

Index First: Creating Spatial Indexes in PostGIS

In this lesson, you will create spatial indexes on geometry columns using PostGIS to enable efficient spatial queries. The lesson focuses on why spatial indexing is essential for scalable proximity analysis in compliance workflows.

Finding Nearby Features with Spatial SQL

In this lesson, you will apply spatial SQL concepts to answer a common real-world question: identifying parcels located within a specific distance of schools. Learners will move from understanding spatial relationships to executing practical PostGIS queries that use distance-based logic. By the end of the lesson, learners will be able to run spatial SQL queries that identify parcels within 100 meters of schools, building confidence in applying PostGIS functions to real analysis tasks.

Understanding Query Performance with EXPLAIN ANALYZE

In this lesson, you will shift focus from writing spatial queries to understanding how those queries perform. Learners are introduced to EXPLAIN ANALYZE and learn how to interpret query execution output to diagnose performance issues. By the end of the lesson, learners will be able to read and explain EXPLAIN ANALYZE results to understand how a spatial query is executed and where optimization opportunities may exist.