Article Tag: GIS

Shapely example: Where to build cell-towers?


Posted on 2024-01-27, by Racum. Tags: GIS Python GeoJSON Shapely

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.

Calculate local time with UTC and location


Posted on 2024-01-05, by Racum. Tags: GIS Python GeoJSON

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.

Converting projections on Shapely


Posted on 2023-12-24, by Racum. Tags: GIS Python GeoJSON Shapely

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.

OpenStreetMap to GeoJSON


Posted on 2023-12-19, by Racum. Tags: GIS OpenStreetMap GeoJSON JSON

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.

Minimal Docker for GeoDjango + PostGIS


Posted on 2023-12-03, by Racum. Tags: GIS Python Django PostgresSQL Docker

If you want to dockerize a GeoDjango project, the most common method is to use an oficial Python image as its base, and install all GIS dependencies over it, being GDAL 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 image to save even more space on your development environment.