# Dependency review for elevation support 1.2.0

Review date: 2026-09-01

## New runtime component

Elevation GeoTIFF input uses Apache SIS `sis-geotiff` 1.6. The artifact is obtained from the official
Apache SIS Maven coordinates and is declared in the core desktop runtime so the worker and desktop
validator share one implementation.

Official sources checked:

- https://sis.apache.org/formats.html
- https://sis.apache.org/apidocs/org.apache.sis.storage.geotiff/org/apache/sis/storage/geotiff/GeoTiffStore.html
- https://repo1.maven.org/maven2/org/apache/sis/storage/sis-geotiff/1.6/

Apache SIS 1.6 is the current stable release shown by the official project documentation at the
review date. It provides the required GeoTIFF `GridCoverageResource` reader, including CRS handling,
tiling and sample decoding. GeoTIFF output is intentionally narrower: the converter writes one-band,
uncompressed WGS84 Float32 strips directly so it can stream large rasters and persist the
`GDAL_NODATA` tag consumed by MapTools. A bounded fallback reads only that single ASCII TIFF tag
when Apache SIS does not expose it as a sample background; it does not decode raster content.

## Compatibility and scope

- Apache SIS is limited to the desktop JVM source set; common selection and format models remain
  platform-independent.
- GeoTIFF export uses WGS 84 geographic coordinates, classic TIFF UInt32 offsets and strips of at
  most 8 MiB. HGT, ASCII Grid and DTED paths do not depend on Apache SIS.
- Final transitive dependency, SBOM and OSV results remain release gates and will be generated by
  `scripts/release-all.ps1` after the implementation block is complete.

No dependency exception is approved by this review. Any unresolved OSV finding blocks release.
