Racummendations (Summaries)

Multi-platform binary releases for a Rust CLI

Racum — Sun, 24 May 2026 00:00:00 +0000

My main issue shipping personal Rust CLI projects was convincing people, especially non-developers, to install a Rust toolchain. So I built binaries for the main desktop operating systems, made them updatable via package managers, and used GitHub Actions to automate the whole process. This article walks through how I did it.

Artemis II: Optical and SAR images compared

Racum — Thu, 02 Apr 2026 00:00:00 +0000

Both my previous and current companies took satellite images from the Artemis II</a> before its launch from the Kennedy Space Center</a> on April 1st, 2026. Planet</a> took an optical image, and ICEYE</a> took a SAR (synthetic-aperture radar) image, and this is the perfect opportunity to compare both technologies.

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Python geometry format conversion cheat-sheet

Racum — Mon, 16 Feb 2026 00:00:00 +0000

If your GIS system is based on the Python/Django/DRF/PostGIS stack, it is very common to perform geometry format conversions between its different layers. This short article includes a cheat-sheet of the most common conversions needed.
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Order in Chaos

Racum — Sun, 01 Feb 2026 00:00:00 +0000

Very cool video about the double-pendulum chaos simulation: Pushing Simulation to the Limit to Find Order in Chaos</a>.

UUIDv7 everywhere

Racum — Tue, 19 Aug 2025 00:00:00 +0000

Looks like UUIDv7</a> is going everywhere! Recently, many languages and databases added native support to it (without extra libraries):
.NET 9</a> (late 2024)</li>
MariaDB 11.7</a> (early 2025)</li>
DuckDB 1.3</a> (middle 2025)</li>
Python 3.14</a> (late 2025)</li>
PostgreSQL 18</a> (late 2025)</li> </ul>

Choose your database identifiers wisely

Racum — Sun, 10 Aug 2025 00:00:00 +0000

When modeling your database, you’ll inevitably need to identify the rows in your tables. This means picking a column to be its primary key; sounds simple enough: maybe just pick an auto-increment or UUID and go with it, right? But this subject is actually way deeper, and I hope I can give you all the tools you need to make an informed decision in this article.
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Time Range on PostgreSQL and Django

Racum — Sun, 03 Aug 2025 00:00:00 +0000

When developing a system that needs to handle time, it is very common to need to track not only “when” something happens, but also “for how long”, for example: event calendars, taxi rides, etc. The most common patterns to solve this problem are start+end and start+duration, but both require two fields in your schema.
Fortunately, PostgreSQL can solve this problem using a range field</a>, a special type of field that encodes the start and end of a numerical series (including time), enabling the use of special functions and operations. The Django framework, trying to be full-feature in relation to PostgreSQL, supports</a> those fields natively.
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Accessing the OpenStreetMap API with Python directly

Racum — Tue, 16 Apr 2024 00:00:00 +0000

On a previous article called "OpenStreetMap to GeoJSON</a>", I explained how to extract Polygons from OSM using an online tool provided by OSM France. And, on this article, I’ll explain how do that yourself directly using the OSM API and Python.
This also explains the basic concepts I used to write the osmexp</a> tool, to export OSM elements into GeoJSON from the command-line.
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Shapely example: Where to build cell-towers?

Racum — Sat, 27 Jan 2024 00:00:00 +0000

This is a fun example of how to use Shapely to solve geographical problems. On this article I show how to cover a polygon with circles in a hexagonal pattern.
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Promoting simple Django fields to ForeignKeys

Racum — Tue, 23 Jan 2024 00:00:00 +0000

Did you ever change your mind about your Django database structure? Sometimes you need to create references between models, but for some reason you didn’t use a ForeignKey field, and there are good cases for that, for example: the ID came from a different system, but you decided to have a local copy. On this article I show how to convert it the proper way.
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Introduction to PostgreSQL Arrays

Racum — Sun, 14 Jan 2024 00:00:00 +0000

Arrays in PostgreSQL are very useful to represent lists of data without the need of extra “many-to-many” tables, but to take advantage of them, you need to know the basics; follow this article to learn them.
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Calculate local time with UTC and location

Racum — Fri, 05 Jan 2024 00:00:00 +0000

When working with remote sensing, it is very common to save time data in a single timezone (usually UTC), this article shows how to convert that into local time based on the provided coordinates.
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The physics of pipe organ

Racum — Thu, 04 Jan 2024 00:00:00 +0000

The company MODARTT</a> develops virtual musical instruments, but not by sampling, they simulate the physics of pianos and organs by modeling how the air (or string for pianos) and the rest of the instrument resonates and transmits the sounds.
They wrote a very interesting article called Organ Physical Modeling</a> where they explain in details how the pressure waves oscillate inside the air pipes; this is focused on pipe organs, but the physics also apply to woodwind instruments with a fipple, like recorders, irish whistles and flutes.
I specially loved this take: ”Organ pipes are DC/AC converters!”.

The Kaiju Preservation Society

Racum — Tue, 02 Jan 2024 00:00:00 +0000

The Kaiju Preservation Society</a>, from John Scalzi. This is a fun novel that re-interprets the “giant monster” lore. Action and comedy are on point, and although it is not futuristic, it is very much a sci-fi story, and a good one!

Running a Rust kernel on JupyterLab Desktop

Racum — Fri, 29 Dec 2023 00:00:00 +0000

If you want to combine the power of Rust with the free-style research orientation of Jupyter notebooks, try using the Rust kernel on it; this allows for an easy prospective approach, making it very similar to Python.
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Converting projections on Shapely

Racum — Sun, 24 Dec 2023 00:00:00 +0000

Sometimes when dealing with coordinates, you may need to work in meters instead of degrees, but, since we don’t live in a flat earth, the calculation is not trivial. Thankfully, there are tools to help with the conversions.
Read more...</a>

OpenStreetMap to GeoJSON

Racum — Tue, 19 Dec 2023 00:00:00 +0000

Use OpenStreetMap as your repository of geometries, and export them in the more convenient GeoJSON format. This technique only works with geometries with area (Polygon and MultiPolygon), points and lines break the exporting tool used here.
Read more...</a>

JSON command-line toolbox (jq, gron, jc, etc)

Racum — Tue, 12 Dec 2023 00:00:00 +0000

The JSON format is the backbone of current Internet protocols and APIs, and this article contains a list of tools to make a better use of it from the command-line, without the need of writing complex programs to read, search, parse, transform and transmit JSON data.
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Minimal Docker for GeoDjango + PostGIS

Racum — Sun, 03 Dec 2023 00:00:00 +0000

If you want to dockerize a GeoDjango</a> project, the most common method is to use an official Python image as its base, and install all GIS dependencies over it, being GDAL</a> the heaviest one, making your final image easily reach the mark of the multi-megabytes. But GDAL is very modular, and most GeoDjango projects can work fine with its basic compilation.
This article shows how to flip that dependency, and use the official minimal GDAL images as a basis, adding the Python/Django structure over it. Also, how to pick a leaner PostGIS</a> image to save even more space on your development environment.
Read more...</a>

Back to Blogging

Racum — Sat, 02 Dec 2023 00:00:00 +0000

After the uncertainty from the Twitter’s nosedive, I decided to revive my blog following the POSSE</a> philosophy (publish own site, syndicate everywhere). I’m not going to delete my social accounts, but now I’ll always write here first.

Sherlock & Co

Racum — Mon, 30 Oct 2023 00:00:00 +0000

Sherlock & Co</a>: a modern take of Sherlock Holmes adventures, with Dr. Watson being the host of a true-crime podcast (very meta!). The first episode is just an introduction, and the episodes 2 to 4 are a 3-parter case!

Paquito D'Riveria - Mozart's Adagio

Racum — Thu, 12 Oct 2023 00:00:00 +0000

Paquito D'Riveria - Mozart's Adagio</a>: a very “jazzy” interpretation of Mozart.

Festival Interceltique de Lorient 2023

Racum — Fri, 29 Sep 2023 00:00:00 +0000

Festival Interceltique de Lorient 2023</a> (in France), with folk bands from all celtic spectrum: from the the classical irish/english ones, to the cultural mixes from Galicia and Asturias! :warning: Warning: contains bagpipes! lots of them!

Gran Turismo

Racum — Fri, 15 Sep 2023 00:00:00 +0000

Gran Turismo</a>: the first 10 minutes may give the impression that it would be a 2h game advertisement., but after the initial exposition it becomes a legit high-production sports movie, based on a real story of a gamer that became a real racing driver.

Unknown: Cosmic Time Machine

Racum — Thu, 27 Jul 2023 00:00:00 +0000

Unknown: Cosmic Time Machine</a>: about the development of the James Webb Space Telescope, on Netflix.

Nuvole Bianche

Racum — Mon, 24 Jul 2023 00:00:00 +0000

Nuvole Bianche</a> (while clouds) from Ludovico Einaudi: a rare mix of melancholy and positive contemplation!

Unravelling the Magic behind Polyrhythms

Racum — Thu, 25 May 2023 00:00:00 +0000

Unravelling the Magic behind Polyrhythms</a>: a very interesting coding video.

Delta-V Series

Racum — Wed, 08 Feb 2023 00:00:00 +0000

Delta-V Series, from Daniel Suarez, with 2 books:
Delta-V</a> (2019)</li>
Critical Mass</a> (2023)</li> </ul>
This is a work of fiction, but very scientifically accurate and plausible for today’s or near-future’s technology.
The first book is all about asteroid mining, and the second one is basically a blueprint for a “space economy”.

Termination Shock

Racum — Mon, 16 Jan 2023 00:00:00 +0000

Termination Shock</a>, from Neal Stephenson. This is a technically a sci-fi book, but very near-future! It happens in a world were climate crisis got out of hand, with droughts and floods everywhere, and an attempt to geo-engineer a solution for that, including all the political repercussions.
This book is recent (from 2021), full of references of current global events, read it before it gets too dated!!

Children of Time Series

Racum — Thu, 01 Dec 2022 00:00:00 +0000

Children of Time Series from Adrian Tchaikovsky: it is kinda of a “first-contact” scenario, but with a twist! ...very entertaining!
Children of Time</a> (2015)</li>
Children of Memory</a> (2019)</li>
Children of Ruin</a> (2022)</li> </ul>

More or Less - Lula’s “zero deforestation” plan for the Amazon

Racum — Mon, 07 Nov 2022 00:00:00 +0000

The episode Lula’s “zero deforestation” plan for the Amazon</a>, from More or Less</a>: a Podcast about statistics hosted by the BBC. That explains why the recent brasilian elections could have a huge impact on the environment in the near future.

Chea de Vida

Racum — Mon, 17 Oct 2022 00:00:00 +0000

Chea de Vida</a> from Guadi Galego: this is an unexpected mix of upbeat and melancholy, sang in the galician language.

Bee and PuppyCat

Racum — Tue, 20 Sep 2022 00:00:00 +0000

Bee and PuppyCat</a>: this is a cute animation that started as a Kickstarter project from an animator that worked on Adventure Time, and now got a fancy remake on Netflix.

Lost Terminal

Racum — Wed, 31 Aug 2022 00:00:00 +0000

Lost Terminal</a>. This is a Sci-Fi story of an AI in orbit trying to figure out what happened to the world below. This feels more like a well-produced audiobook, but in the format of weekly episodes or ~15 minutes.

Short trailer</a></li>
Direct RSS Feed</a></li> </ul>

Lady Astronaut Series

Racum — Thu, 25 Nov 2021 00:00:00 +0000

Lady Astronaut Series: it starts as alternate history and becones sci-fi: a meteor falls on earch in the 50s, starting a mass-extinction event process, that forces the countries to colaborate and bootstrap the space-age earlier.
The Calculating Stars</a> (2018)</li>
The Fated Sky</a> (2018)</li>
The Relentless Moon</a> (2020)</li> </ul>

The Ministry for the Future

Racum — Mon, 13 Sep 2021 00:00:00 +0000

The Ministry for the Future</a>, from “Kim Stanley Robinson”: it is technically Sci-Fi, but depicts a present to near future with natural and humanitarian disasters triggered by climate change.

Project Hail Mary

Racum — Mon, 10 May 2021 00:00:00 +0000

Project Hail Mary</a> from Andy Weir: t has the same problem-solving vibe from The Martian, but written in a different, non-linear way!

Light Speed

Racum — Tue, 05 Jan 2021 00:00:00 +0000

Light Speed</a> from Seeker’s YouTube channel: a close look into the race of solar cars that happens every two years in the australian Outback.

Connected

Racum — Wed, 05 Aug 2020 00:00:00 +0000

Connected</a> on Netflix: it is a series of documentaries about unlikely connections around us.

Sergio

Racum — Mon, 20 Apr 2020 00:00:00 +0000

Sergio</a> on Netflix: it is about an UN human-rights representative who died in Iraq in 2003 and was responsible for the stablishment of East Timor in 2000. About 1/3 of the movie happens in East Timor, where I lived from 2005-2006; it was nice to see it portrait in a movie!

The Case of the Missing Hit

Racum — Tue, 10 Mar 2020 00:00:00 +0000

The episode #158 The Case of the Missing Hit</a> from the podcast Reply All</a>: it’s a detective/archelogy work to solve a great musical mistery with a very satisfying end.

Apollo Guidance Computer Restoration

Racum — Fri, 19 Jul 2019 00:00:00 +0000

Apollo Guidance Computer Restoration</a> on YouTube: this shows a many-month-task-force to restore one of the few surviving Apollo computers, they went very deep into the specifications, blueprints, and needed to borrow modules from other computers like it in museums to copy the data still there! …it is not for everyone, but may have a good hit-rate with my friends!

PodPesquisa

Racum — Thu, 03 Jan 2019 00:00:00 +0000

Long time ago, when I lived in Brazil, I used to participate on the “New Media” movement. My biggest contribution was the participation on the PodPesquisa, a national survey about the podcast listeners. My role was increasing between iterations, from just data analysis on 2008 to lead the its development and run on 2014.
Here is the list of compiled results by year (in portuguese):
2008</a></li>
2009</a></li>
2014</a></li> </ul>

About

Racum — Wed, 02 Jan 2019 00:00:00 +0000

Welcome to Racummendations! ...this is where I post my recommendations, opinions and thoughts about anything, but mostly technology, Sci-Fi books, games and other nerd stuff.
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