Shortest Path Routing with PostGIS - PGRouting - Network Analysis - Complete Web Project - Part 1

In this first part of the series, we lay the foundation for building a routing system by preparing the road geometry for network analysis.

We begin with a raw road dataset (MultiLineString) and perform the following essential steps:

✅ What’s Covered in this Video:

• Convert MultiLineString to 2D LineString:
  Routing algorithms require simple, clean line geometries. We break down complex geometries using ST_Dump and enforce 2D lines with ST_Force2D.

• Reproject to EPSG:4326 (WGS 84):
  Standardizing the coordinate reference system ensures compatibility with QGIS, web maps, and GPS systems.

• Insert Clean Lines into grid_lines Table:
  A new table is created to hold the processed road segments which will later be used to extract nodes and edges.

• Create a Spatial Index:
  To improve performance in later spatial operations (like nearest neighbor and intersections), a GIST index is applied.

💡 Why This Step Matters:

This step is critical to ensure our dataset is optimized, standardized, and ready for generating network nodes and building the graph for shortest path analysis.

In the next part, we’ll extract network nodes from these lines and begin constructing the routing graph.