shboost24-cmd

name	shboost24-cmd
description	Generate colour-magnitude diagrams from SHboost24 data using local Parquet caching and agreed plotting conventions.
version	1.0.0
author	AstroAgent / AIP
license	MIT
metadata	{"hermes":{"tags":["astronomy","shboost24","plotting","parquet","cmd"],"category":"astronomy","related_skills":["starhorse-access","data-aip-de-s3","cmd-plotting","reana-shboost24","s3-parquet-sampling","dask-hvplot-datashader-scientific-plots"]}}

SHboost24 CMD

When to Use

Use this skill when generating CMD plots from SHboost24 parquet data, especially from S3-backed datasets with local Parquet caching.

Procedure

1. Check whether a local cached Parquet subset already exists.
2. If the source data is huge, read and reduce it with Dask first.
3. Keep only the required columns before plotting.
4. Cache the working table locally as Parquet before repeated plotting.
5. Prefer hvplot for scientific interactive/clean plotting.
6. For dense or very large data, prefer Dask + hvPlot + Datashader (rasterize=True / datashade=True).
7. Preserve original axes and invert only the y-axis.
8. Save PNG only unless the user explicitly asks otherwise.

Pitfalls

• Do not emit PDF by default.
• Do not transform axes unless explicitly requested.
• Avoid reading unnecessary columns from very large parquet datasets.
• Do not skip the local cache step for S3-derived data you will revisit.
• Do not force raw-point plotting for dense large catalogs when Datashader would communicate the structure better.

Verification

• Output file exists and is PNG.
• The plot uses hexbin density.
• The y-axis is visually inverted only.