{"id":"https://data.mapsnap.org/runs/v2.0/iiif/chronoscope/sanborn01790_090.keymap.iiif.json","type":"AnnotationPage","@context":["http://www.w3.org/ns/anno.jsonld"],"label":"Chicago, Illinois | 1950 | key map | mapsnap generated fit (2026-10-16)","creator":{"type":"Software","name":"mapsnap","homepage":"https://mapsnap.org"},"rights":"https://opendatacommons.org/licenses/odbl/1-0/","metadata":[{"label":"generated","value":"2026-10-16"},{"label":"run","value":"corpus-v2"}],"items":[{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000a/georef","type":"Annotation","@context":["http://iiif.io/api/extension/georef/1/context.json","http://iiif.io/api/presentation/3/context.json"],"label":"Chicago, Illinois | 1950 | sanborn01790_090 p0a","metadata":[{"label":"streets","value":"70"},{"label":"intersections","value":"252"}],"created":"2026-10-16T22:19:56Z","modified":"2026-10-16T22:19:56Z","motivation":"georeferencing","target":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000a/selector","type":"SpecificResource","source":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000a","type":"ImageService3","width":1477,"height":1831},"selector":{"type":"SvgSelector","value":"<svg><polygon points=\"0.0,1831.0 0.0,0.0 1477.0,0.0 1477.0,1831.0 0.0,1831.0\" /></svg>"}},"body":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000a/gcps","type":"FeatureCollection","transformation":{"type":"helmert"},"features":[{"type":"Feature","properties":{"resourceCoords":[1127.2,1019.4],"type":"gcp"},"geometry":{"type":"Point","coordinates":[-87.6535511,41.8370435]}},{"type":"Feature","properties":{"resourceCoords":[331.8,1360.7],"type":"gcp"},"geometry":{"type":"Point","coordinates":[-87.6788858,41.8285394]}}]}},{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000b/georef","type":"Annotation","@context":["http://iiif.io/api/extension/georef/1/context.json","http://iiif.io/api/presentation/3/context.json"],"label":"Chicago, Illinois | 1950 | sanborn01790_090 p0b","metadata":[{"label":"streets","value":"41"},{"label":"intersections","value":"196"}],"created":"2026-10-16T22:19:56Z","modified":"2026-10-16T22:19:56Z","motivation":"georeferencing","target":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000b/selector","type":"SpecificResource","source":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000b","type":"ImageService3","width":1464,"height":1831},"selector":{"type":"SvgSelector","value":"<svg><polygon points=\"0.0,1831.0 0.0,0.0 1464.0,0.0 1464.0,1831.0 0.0,1831.0\" /></svg>"}},"body":{"id":"https://cdn.chronoscope.io/mapsnap/service:gmd:gmd410m:g4104m:g4104cm:g01790195004:01790_04_1950-0000b/gcps","type":"FeatureCollection","transformation":{"type":"helmert"},"features":[{"type":"Feature","properties":{"resourceCoords":[717.5,1427.2],"type":"gcp"},"geometry":{"type":"Point","coordinates":[-87.6204566,41.8274391]}},{"type":"Feature","properties":{"resourceCoords":[41.5,1586.2],"type":"gcp"},"geometry":{"type":"Point","coordinates":[-87.642274,41.8235005]}}]}}]}