Automatic building detection using aerial view

On June 30 and July 1, the fourth of the seven special training actions was carried out in the framework of the CV Special Rolling Work Plan.

The session was conducted by Ana Mateo . She is Deputy Director General of the Valuation and Inspection Department at the Spanish Catastro. He has more than 15 years of experience working in the Spanish Cadaster mainly in the valuation and inspection services.

Summary

Automatic building detection using aerial view. This training action was focused on techniques for aerial and non-aerial detection of buildings, management tasks and benefit analysis, regulation design and a special overview of relevant Spanish practices.

In 2013-2018, the General Directorate of the Spanish Cadastre carried out a special plan of activities, called a plan of cadastral regularization, that was supposed to update construction data in more than 2 million parcels.

The plan was based on the detection of omitted constructions, extensions and other works by means of comparing cadastral cartography with orthophotographs of the land. In addition, in some cases, facade photographs were taken, which made it possible to detect the remodeling of buildings, such as the construction of an additional floor.

Currently, an attempt is being made to carry out some automated detection tests based on the comparison of orthophoto coverage of different dates, pixel by pixel, by artificial intelligence and with the help of LIDAR. But for now these are only tests.

Objectives

The objectives of the training action are the following:

  • To identify the needs to be met;
  • To know the technological options for automatic building detection, their characteristics and applications in a theoretical way;
  • To know the techniques developed by Spain and their practical application;
  • To see how the Spanish Cadastre implemented the Cadastral Regularization Plan in order to detect and incorporate omitted buildings into the system;
  • To apply the new knowledge to the design of actions to be taken

See the presentation…


Spanish building detection practices: The regularization plan

The regularization plan included a programme of activities aimed at detecting omitted buildings and construction alterations, obtaining relevant information from municipal archives and incorporating the fresh data into the cadastre.

After making an initial analysis of omissions detected by contrast between orthophotography and cadastral maps it was estimated that it would be necessary to update 2.4 million properties.

The regularisation procedure in contrast with the traditional inspection is a fast and agile procedure, which consists of detecting an omission, searching for the necessary documentation, communicating with the person concerned, collecting the regularisation fee, and finally incorporating the new data into the Cadaster systems.

See the presentation…


Conclusions

  • Spanish Cadastre successfully implemented this ambitious plan
  • The plan contributed to improving the quality of the cadastral data base of buildings
  • The regularization campaign was accepted by citizens (with conflicts occurring in less than 1.5% of cases)
  • It helped in fighting real estate tax fraud
  • and it made it possible to boost local finance

“…We received 40 million euros per year in budget funds to carry out the plan. For every euro invested, 17 was recovered in the form of property tax revenue…”


Access to recorded video sessions


Documentation

In the training action folder you will find all the documentation used in the different sessions.

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