The landscape in front of you, as it was seventy years ago.

As a telescope looks far away in space, a chronoscope looks back in time. On a mountain you see how far the glacier reached; on a beach where the shoreline ran; on a town what it was like before the earthquake. And, where the data allow, how far the sea could reach in 2100. It isn't a filter: it is the same place, with a drawing of how it used to be on top.

Cronoscopio is about Italy only: its places, with the surveys and aerial photos of its public bodies.

Yesterday

The aerial photos taken over Italy from 1954 onwards, historical maps back to the nineteenth-century cadastre, and the lines that research bodies have derived from them: the outlines of glaciers, the coastline, landslides, land use.

Today

The same place now, at the same scale and from the same point — so that the difference speaks for itself, with no need to explain it.

Two ways of looking

From the groundOn a view of the place lined up by us, to look at even from home; on a photo of yours, if you took it at one of the places; or live, with the camera: the app recognises the outline of the mountains against the sky, works out where you are looking from, and draws the glacier of the past on the real terrain.
From aboveTwo eras side by side and a slider you drag: on one side the aerial photo of one year, on the other that of another. Anywhere in Italy, for free: the national aerial photos from 1988 to 2012, beside today's map, and where the Regions publish them also the 1954 flight and those of recent years. At the curated places, in addition, historical maps dated from their content, glacier outlines year by year, shorelines, the sea expected in 2100. It also works offline, on places you have downloaded, and can be opened big on a computer screen.

Thirty curated places, to begin with

Besides the map of all of Italy, there are the places we have prepared one by one: chosen because change can be seen there, with views from the ground, traced lines, dated maps, and a card that says what to look for and where each image comes from.

These are the first thirty. The list will grow over time: we are preparing more, and those with the full version get them without paying again.

Glaciers: Marmolada, Forni, Solda–Ortles, Adamello, Pale di San Martino, Lys, Miage, Brenva, Rutor
Coasts: Po Delta, Comacchio, Ravenna, Venice Lido, Tiber mouth, Circeo, Poetto, Scala dei Turchi, Bagnoli, Bari Punta Perotti, Genoa Pra'–Voltri
Lakes and rivers: the bell tower of Curon in Lago di Resia, the Vajont, the Po Delta, the Tiber mouth, Carezza, Conza, Faenza
Cities: East Rome along the Via Casilina, Genoa with the Morandi bridge and Pra'–Voltri, Bagnoli, Bari Punta Perotti, the Poetto in Cagliari, Faenza
Events: the earthquakes of Amatrice, Conza and Gibellina; the Faenza flood; the Vajont and Civita di Bagnoregio landslides; the Carezza forest flattened by storm Vaia; the collapse of the Morandi bridge

These are the same headings as the app's filters, and a place can be under more than one.

Built on public data

Cronoscopio doesn't produce data of its own: it shows, putting it in order, material that Italian public administrations have already digitised and published, and that today lives in geoportals almost nobody opens. Each source is used on the terms its owner has stated, and the attribution is given in the app, in the “Info” card of every view.

National orthophotos 2022–2024 — AGEA: CC BY 4.0
Orthophotos 1988–2012 and IGM maps — National Geoportal, Ministry of the Environment and Energy Security: with credit to the source
Orthophotos, 1858 cadastre and glacier inventory — Provincia autonoma di Bolzano: CC0 1.0 · CC BY 4.0
Historical and recent orthophotos — Provincia autonoma di Trento: CC BY 4.0
Historical and recent orthophotos — Regions of Lazio, Emilia-Romagna, Toscana, Valle d'Aosta: CC BY
Orthophotos 2018 and 2021 — Comune di Genova: CC BY 4.0
Land-use maps — Regions and autonomous Provinces: CC BY 4.0 · IODL 2.0 · CC0
Historical coastline, beaches and landslides (IFFI) — ISPRA: CC BY 4.0 · CC BY-SA 4.0
LIDAR surveys — Ministry of the Environment and Energy Security: CC BY 4.0
TINITALY terrain model — INGV: CC BY 4.0
Sentinel-2 satellite images and emergency maps — Copernicus (European Union): free use with citation
1943 maps of Italy — U.S. Army Map Service: public domain
Glacier outlines — GLIMS Glacier Database, NSIDC: citation required
Municipal boundaries and names — ISTAT: CC BY 4.0
Today's map — OpenStreetMap, via OpenFreeMap: ODbL 1.0
Landscape photos — Wikimedia Commons: CC BY / CC BY-SA, author by author

Where it stands

Cronoscopio, for iPhone and iPad, is on the App Store, in English and Italian. Free: the comparison of aerial photos anywhere in Italy, land use and six of the curated places, with three years each; the place you are in you see in full. A one-time purchase, with no subscription, opens all the places, all the years and the historical maps, including the places we will add. No account, no advertising, no tracking.