Skip to content
ES
2026— Early scaffolding

Radar Siting Toolkit

Open-source QGIS plugin answering where weather radars should be sited, and what each configuration would actually see.

The toolkit running inside QGIS: the “Evaluate candidate sites” dialog with its execution log over a hillshaded GLO-30 elevation model of Jamaica, the plugin's four algorithms in the processing toolbox on the right, and the output layers — per-azimuth blockage, PPI-style sector and range blockage, and site summary — in the layer panel on the left.
A run over Jamaica: 1° azimuth step, 1° beamwidth, 0.5° elevation, effective earth-radius factor k = 1.333. The help panel on the right is the tool saying in its own interface what the run does not include — merit scores weighted by importance need an area-of-interest grid, which this algorithm does not build.

The problem. Siting a radar network is an investment decision made by a government or a donor. It needs reproducible geometric evidence, not a pretty coverage picture.

The decision that matters. For each azimuth the terrain is sampled along the ray at native DEM resolution, accumulating the maximum horizon angle seen up to each range, corrected for earth curvature by an effective-radius factor. Minimum clear elevation and minimum visible height fall out directly — a single O(N) pass per ray, with no discrete elevation-angle loop.

A detail that is easy to get wrong. Partial beam blockage is published as the range-cumulative maximum, never as raw per-bin PBB. Publishing per-bin values produces wrong maps across the entire sector behind an obstacle.

A dependency refused on purpose. Implemented in plain numpy. wradlib would pull in scipy, matplotlib, xarray and xradar and recommends a conda install — which cannot be installed from the QGIS Plugin Manager, where the users actually are. wradlib is used offline, as a validation reference only.

Explicitly out of scope

  • Rain attenuation and frequency-band selection
  • Real anomalous propagation — only the effective earth-radius factor is parameterised
  • Sea clutter, ground clutter, RF interference, spectrum compatibility
  • Quantitative precipitation estimation and nowcasting
  • Tower structure, radome, wind load, electrical resilience
  • Cost, lifecycle and staffing

This toolkit covers roughly 15% of a full siting study. Saying so is the point: the number that is defensible is worth more than the number that is impressive.

Source →