Latest posts from Paul Ramsey

The pg_featureserv micro-service is a thin middleware that binds tables and functions in a PostgreSQL database to a JSON collections API, accessible over HTTP. Using the Crunchy Bridge

A community member on the postgis-users mailing list had a question recently:

I have a table of elevation points, and I would like to figure out an elevation profile for a flightline running through those points. How?

This question is a nice showcase of some of my favorite spatial tools

Last month, just under the wire for a 2021 release, the 3.2 version of PostGIS hit the streets! This new PostGIS also supports the latest 3.10 release of GEOS, which underpins a few of the new features.

Raster Algorithms

While supporting Crunchy Spatial and Crunchy Bridge clients, I’ve been thinking about how I usually clean messy data. I wanted to talk about regular expressions (regex

One of the curious aspects of spatial indexes is that the nodes of the tree can overlap, because the objects being indexed themselves also overlap.

That means that if you're searching an area in which two nodes overlap, you'll have to scan the contents of both nodes. For a trivial example above, that's not a big deal, but if an index has a lot of overlap, the extra work can add up to a measurable query time difference.

The PostGIS spatial index is based on a R-tree

PostgreSQL can provide high performance summaries over multi-million record tables, and supports some great SQL sugar to make it concise and readable, in particular aggregate filtering, a feature unique to PostgreSQL and SQLite.

A huge amount of reporting is about generating percentages: for a particular condition, what is a value relative to a baseline.

Some Sample Data

Raster data access from the spatial database is an important feature, and the coming release of PostGIS will make remote access more practical by allowing access to private cloud storage.

Previous versions could access rasters in public buckets, which is fine for writing blog posts

One theme of the 3.2 release is new analytical functionality in the raster module, and access to cloud-based rasters via the "out-db" option for rasters. Let's explore two new functions and exercise cloud raster support at the same time.

OpenTopography