A IIIF Georeference Extension annotation body plus the image it places
(overlays[].georeference). The body is the annotation payload of
iiif.io/api/extension/georef verbatim: a GeoJSON FeatureCollection of
ground control points pairing properties.resourceCoords (image pixels)
with geometry.coordinates (WGS84 lon/lat), optionally carrying a
transformation hint.
The viewer fits the affine (first-order polynomial) case and places the
image with OpenLayers' reprojection, which requires an axis-aligned
placement; rotated or skewed sheets, higher-order polynomials and thin
plate splines are reported and skipped — see the "Geo-referenced layers"
section of docs/storymap-as-iiif-manifest.md.
A IIIF Georeference Extension annotation body plus the image it places (
overlays[].georeference). Thebodyis the annotation payload ofiiif.io/api/extension/georefverbatim: a GeoJSON FeatureCollection of ground control points pairingproperties.resourceCoords(image pixels) withgeometry.coordinates(WGS84 lon/lat), optionally carrying atransformationhint.The viewer fits the affine (first-order polynomial) case and places the image with OpenLayers' reprojection, which requires an axis-aligned placement; rotated or skewed sheets, higher-order polynomials and thin plate splines are reported and skipped — see the "Geo-referenced layers" section of docs/storymap-as-iiif-manifest.md.