Aerial photos since 1956: spotting extensions and changes on a Spanish property

The pool next to the terrace. A guest house at the bottom of the garden. A covered porch that has become a room. In the listing it all looks as if it came with the house. For a buyer, two things count: since when each of these structures has stood, and whether the cadastre and the land registry know about them.

The first question has an official answer from above. Spain has been photographed from the air many times over, and the Fototeca Digital of the Centro Nacional de Información Geográfica (CNIG) holds flights from a period that runs from 1929 to the present. It shows them online, free to view.

Which official aerial photo series cover Spain?

For a house purchase, the series that matter are the ones available as orthophotos, images corrected so that they sit accurately on a map. The oldest of those with near-national coverage is the American flight known as Series B, flown between January 1956 and November 1957. Several Spanish flights follow, and since 2004 the national aerial photography plan, the Plan Nacional de Ortofotografía Aérea (PNOA).

1. Series A1945 to 1946American flight over mainland Spain; frames can be viewed in the Fototeca but not downloaded
2. Series B1956 to 1957Mainland Spain and the Balearic Islands, not the Canary Islands, Ceuta or Melilla; black-and-white orthophotos, pixel 0.50 to 1 m
3. Series C1967 to 1968American flight; single frames only, no orthophotos
4. Interministerial1973 or 1976 to 1986Orthophotos only for five regions; pixel 0.25 to 0.50 m
5. Vuelo Nacional1980 or 1981 to 1986Coordinated by the IGN; black-and-white orthophotos, pixel 0.50 to 1 m
6. Olistat and SIGPAC1997 to 2003Flights for the agriculture ministry; Olistat only over the 34 olive-growing provinces
7. Quinquenal1998 or 1999 to 2003IGN flight planned in five-year cycles
8. PNOAsince 2004All of Spain, currently renewed every 3 years; 25 cm resolution, 15 cm in some areas

Series A is older still. The US Army Map Service flew it between the end of January 1945 and early October 1946, at an approximate scale of 1:43,000. Its frames can be viewed in the Fototeca but are not available for download.

Series B, the workhorse for older comparisons, is in black and white at an approximate flight scale of 1:32,000, with orthophoto pixels between 0.50 m and 1 m. The IGN has no record of it being flown over the Canary Islands, Ceuta or Melilla.

Three series carry different start years on different official pages. The Fototeca guide dates the interministerial flight from 1973, while the IGN's PNOA page and the CNIG download page give 1976. The Vuelo Nacional appears as 1980 to 1986 in one place and 1981 to 1986 in another, and the Quinquenal flight as starting in 1998 or 1999. For dating a pool this hardly matters. You read the date from the individual image anyway.

Regional gaps matter more. The interministerial orthophotos exist only for Andalusia, Extremadura, Castilla y León, La Rioja and the Basque Country.

How do you find one property in the Fototeca?

By its cadastral reference, an address or a place name. The reference is the surest of the three because it identifies exactly one plot; how it is built and where to find it is explained in our guide to the Spanish cadastral reference.

The Fototeca shows single frames and orthophotos, both from the historical flights and from the PNOA flights since 2004. Some frames can be downloaded.

If you work with mapping software, the same material is available as a web map service. The WMS service Ortofotos históricas y PNOA anual carries the annual PNOA orthophotos together with the orthophotos of SIGPAC, Olistat, the Vuelo Nacional, the interministerial flight and Series B. Load two years on top of each other and switch between them. A new pool stands out at once. So does a new roof.

One limitation applies to the old analogue flights. Their frames carry only approximate coordinates for the centre of the image, so the plot you are looking for can sit some way off the spot where the search places it. Check the surroundings, such as roads, field boundaries and neighbouring houses, before you draw a conclusion.

Single frame or orthophoto: which one shows what?

Both have their use, and the Fototeca's own guide spells out the difference. A single frame (fotograma) is one exposure taken from the aircraft. An orthophoto is assembled from several such frames and corrected to the geometry of a map.

In practice that splits the work. The orthophotos tell you between which flights an extension appeared, and they let you measure its footprint. The single frame pins down a day. The resolution sets the limit of detail: current PNOA orthophotos have a pixel size of 25 cm, in some areas 15 cm, while the Series B orthophotos have 0.50 to 1 m.

Does the cadastre record the extension?

It should. The Spanish cadastre describes every property with, among other things, its surface area, its use, the quality of its construction and a graphic representation (Art. 3 of the consolidated cadastre law, Texto refundido de la Ley del Catastro Inmobiliario, TRLCI, Real Decreto Legislativo 1/2004, consolidated text last updated on 24.12.2022). These data are presumed correct until proven otherwise. The legal statements of the land registry take precedence over them.

Recording changes is compulsory (Art. 11 TRLCI), and the holders of rights in the property, such as the owners, must declare them (Art. 13 TRLCI). The duty covers new buildings and the extension, refurbishment, alteration or demolition of existing ones, in whole or in part; mere maintenance and purely decorative work fall outside it (Art. 16 TRLCI, version of 25.06.2015).

For buildings the two-month deadline runs from the date the works were finished (Art. 28.2 Real Decreto 417/2006, consolidated text last updated on 18.12.2007). New buildings and extensions are declared on form 900D.

One rule on that form matters to buyers. A current owner can also declare changes that were made before they acquired the property and are missing from the cadastre (Orden HAC/1293/2018, Art. 2). The declaration needs a document proving the completion date: a final works certificate (certificado final de obra) or a technical certificate endorsed by the professional body, a deed declaring completion, or failing those any other document that shows the date. Whether a certified aerial frame is accepted for this, the order does not say expressly.

Where the cadastral description and the property on the ground differ, the cadastre's electronic office (Sede Electrónica del Catastro) takes written submissions about discrepancies. The orthophoto gives you something concrete to compare: the footprint you can measure from above against the surface the cadastre records.

How does a building get into the land registry?

Through a declaration of new building (declaración de obra nueva) in a notarial deed, which is then entered in the land registry (Registro de la Propiedad). For the deed of a finished new building, Article 28 of the Ley de Suelo (Real Decreto Legislativo 7/2015, article in its original version of 31.10.2015, consolidated text last updated on 25.05.2023) requires a certificate from a competent technician that the works were completed, together with the documents showing the required licences or notifications.

For older buildings, Article 28.4 provides a second route. It applies to buildings against which measures involving demolition can no longer be taken because the relevant limitation periods have run out. On this route the deed can be registered with, among other documents, a cadastral certificate showing completion on a specific date; a certificate from the town hall or a technician, or a notarial record describing the property, are the alternatives. This is where the cadastre and the land registry meet. Where the entry was made without a certificate from the town hall, the town hall must have the specific planning situation of the building recorded by a marginal note in the land registry. Article 28 does not set the length of those limitation periods itself.

The registry also needs to know where the building stands. The ground it occupies must be identified by geographic coordinates (Art. 202 Ley Hipotecaria, version of 25.06.2015, in force since 01.11.2015).

What should you ask the seller, the town hall and your lawyer?

Start from the comparison. If the 1956 to 1957 image shows a small house and today's shows a pool, an extension and a second building, you have a list of structures and a period for each one. The questions follow from that.

Ask the seller, for each structure that appears in later images:

• Is there a licence or notification from the town hall for it?
• Is it in the cadastre, with a surface that matches what you can measure on the orthophoto?
• Is it declared as obra nueva in the land registry, and is there a final works certificate?
• If it was added late, was the change declared to the cadastre on form 900D?

Ask the town hall what it holds on file for the property and its buildings, and whether a marginal note on the planning situation has been entered in the land registry.

Ask your Spanish lawyer (abogado) to read the land registry extract (nota simple) against the cadastral certificate and against the dates from the aerial photos, and to tell you which route any obra nueva was registered by. Where a structure appears between two flights and no document covers it, the photos narrow down the period to be clarified. That can be done before the signing at the notary.

At the signing itself, the notary asks the parties whether the description in the cadastral certificate matches the physical reality of the property at that moment (Art. 18 TRLCI). Differences in the shape and area of the plot can be corrected there. It helps to have done the comparison before that question is asked. Our overview of checks before buying property in Spain sets out the other documents worth requesting.

Which years does the property report show?

For 431 checked properties, the property report contains aerial photos (as of 29.09.2026). These figures describe the properties checked, not Spain as a whole. For 421 of them the 1956 to 1957 flight is included, in line with its coverage of the mainland and the Balearic Islands. The two flights of the 1970s and 1980s appear less often because their orthophotos cover only some regions.

• 1956 to 1957 (Series B)421mainland and Balearic Islands
• Interministerial64five regions only
• Vuelo Nacional112some regions only
• 1997 to 2003 (SIGPAC, Olistat)430
• around 2005 (PNOA)430
• around 2010 (PNOA)430
• around 2015 (PNOA)430
• around 2020 (PNOA)429
• current (PNOA)429

You do not have to assemble the comparison yourself. The property report shows the available years side by side, each with the plot boundary from the cadastre drawn in. What else the property check covers is set out on its overview page.

In short

• The Fototeca Digital holds Spanish aerial flights from 1929 onwards and finds a plot by its cadastral reference.
• Series B of 1956 to 1957 is the oldest near-national orthophoto series, covering the mainland and the Balearic Islands; PNOA images since 2004 are currently renewed every 3 years.
• A single frame carries an exact date and can be certified; an orthophoto can be measured but not certified.
• New buildings and extensions must be declared to the cadastre within two months of completion, and a current owner can declare older changes on form 900D.
• The aerial photo dates a structure. The town hall, the cadastre and the land registry say what is on record for it.