Migrating From X-STILT

X-STILT users usually care about column-aware geometry, weighting and chemistry transforms, and product-driven observation workflows. PYSTILT now has first building blocks for those, but it remains more generic than X-STILT in this alpha.

X-STILT concept	X-STILT API / file	PYSTILT equivalent
Column receptor definition	X-STILT column setup scripts	stilt.observations.ColumnSensor and receptor builders
Vertical weighting	custom AK × PWF logic	VerticalOperatorTransformSpec in FootprintConfig.transforms
First-order chemistry	chemistry hooks	FirstOrderLifetimeTransformSpec
Scene grouping	product-level grouping logic	stilt.observations.Scene plus grouping helpers
Column footprint outputs	X-STILT column products	standard PYSTILT footprint outputs from column/slant receptors
Observation normalization	built-in product readers	generic Observation and sensor interfaces

Current boundary

PYSTILT intentionally stops at a generic observation layer. It does not yet ship a large catalog of product-specific X-STILT file readers or retrieval pipelines inside the core package.

Practical migration strategy

1. normalize your product data into Observation objects

2. use PointSensor or ColumnSensor to build receptors

3. encode reusable transforms declaratively where possible

4. keep product-specific I/O in your application layer until the alpha API settles