{"id":"https://data.mapsnap.org/runs/v2.0/iiif/chronoscope/sanborn01790_043.keymap.iiif.json","type":"AnnotationPage","@context":["http://www.w3.org/ns/anno.jsonld"],"label":"Chicago, Illinois | 1920 | key map | mapsnap generated fit (2026-10-17)","creator":{"type":"Software","name":"mapsnap","homepage":"https://mapsnap.org"},"rights":"https://opendatacommons.org/licenses/odbl/1-0/","metadata":[{"label":"generated","value":"2026-10-17"},{"label":"run","value":"corpus-v2"}],"items":[{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790192024:01790_24_1920-0000/georef","type":"Annotation","@context":["http://iiif.io/api/extension/georef/1/context.json","http://iiif.io/api/presentation/3/context.json"],"label":"Chicago, Illinois | 1920 | sanborn01790_043 p0","metadata":[{"label":"streets","value":"63"},{"label":"intersections","value":"449"}],"created":"2026-10-17T01:25:23Z","modified":"2026-10-17T01:25:23Z","motivation":"georeferencing","target":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790192024:01790_24_1920-0000/selector","type":"SpecificResource","source":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790192024:01790_24_1920-0000","type":"ImageService3","width":1407,"height":2063},"selector":{"type":"SvgSelector","value":"<svg><polygon points=\"0.0,2063.0 0.0,0.0 1407.0,0.0 1407.0,2063.0 0.0,2063.0\" /></svg>"}},"body":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790192024:01790_24_1920-0000/gcps","type":"FeatureCollection","transformation":{"type":"helmert"},"features":[{"type":"Feature","properties":{"resourceCoords":[997.0,1673.7],"type":"gcp"},"geometry":{"type":"Point","coordinates":[-87.6858485,41.770122]}},{"type":"Feature","properties":{"resourceCoords":[273.4,1619.9],"type":"gcp"},"geometry":{"type":"Point","coordinates":[-87.7176715,41.7714616]}}]}}]}