Tutorial

Fit a finer input layer (e.g. admin3) into a coarser overlay layer (e.g. admin0), with no gap or overhang at the edge, then re-fit it when the overlay layer changes.

Fit a raw layer to an overlay layer¶

edge-match extends each input feature outward with Voronoi diagrams, then clips it to its overlay feature, in one call:

topo-tools edge-match adm3.gpkg adm0.gpkg adm3_matched.gpkg \
  --issues-file match_report.gpkg

Add --fill-schema to cascade admin-hierarchy columns down to each row's real depth before export.

Re-fit to a new overlay layer¶

When only the overlay layer changes, edge-mosaic re-clips an already-fitted layer against it, skipping Voronoi extension entirely:

topo-tools edge-mosaic adm3_matched.gpkg adm0_new.gpkg adm3_mosaicked.gpkg \
  --issues-file mosaic_report.gpkg

The primitives underneath¶

edge-match and edge-mosaic chain three primitives, each also runnable on its own for a narrower job: edge-extend (extend a layer outward with no overlay to fit), edge-clip (assign each input feature to an overlay feature and clip it), and edge-stitch (close seams in an already-tiled layer).

See the edge-match, edge-mosaic, edge-extend, edge-clip, and edge-stitch references for details.