sdr-heatmap 
I'm using this as an opportunity to learn Rust.
A tool to visualize files generated by rtl_power. Inspired by heatmap.py. It aims to provide better speed than heatmap.py, while keeping the same image format. Another similar tool is rtl-gopow, but it produces a different (IMO inferior) image than heatmap.py.
Installation
cargo install sdr-heatmap (from crates.io)
Speed (WIP) (v0.1.2)
| Benchmark | sdr-heatmap | heatmap.py | rtl-gopow | Notes |
|---|---|---|---|---|
| 14 MB | 375 ms | 4558 ms | 1995 ms | |
| gzipped 44 MB | 14 s | failed after 3 m | gz not supported | Raspberry Pi 3B+ |
| 44 MB | 17 s | 801 s | 141 s | Raspberry Pi 3B+ |
| 829 MB | 19,37 s | 268,26 s | 141,34 s | |
| 829 MB | 611 MB | 427 MB | 5164 MB | Peak memory, using time -v, single run, v0.1.3 |
See raw results in bench.md