Tiago Candeias > ACID


ACID is the acronym of Automatic Cadastral Information Digitalization.


In Portugal, the cadastral information is not digitalized yet and there are many old sheets in A0 size that need to be converted to the digital format.

The manual digitalizing is a slow, repetitive and tedious task, needing in average more than 8 hours for one cadastral sheet. The automatization allows the digitalizing and the extracting of secure information from maps. Some zones with mistaken information are marked for further correction by hand.

A parcel has a closed contour, a circle, a number and a land type. The parcel's elements are in the inner contour and the number is inside of the circle. When a parcel have different land types, the dashed lines are used to divide it into subparcels that have their own numbers and land types.

The information is extracted, organized and at the end the cadastral entities are obtained.


The prototype recognizes the following patterns:
  • Crosses
  • Circles
  • Arcs
  • Dashed lines
  • Characters
  • Contours
After the recognition, the cadastral entities are extracted, through:
  • Grouping characters in words
  • Associating a number with a parcel
  • Grouping the parcel's elements


The interface shows the results in a complete cadastral sheet.

Screen Shots

Some images of the prototype in different maps:

People involved

  • I am working on this project since September-2001;
  • Ruben Oliveira finished his work in September-2002;
  • Filipe Tomaz finished his work in September-2002;
  • Prof. Hamid Shahbazkia is the responsable researcher of this project.
    Print Version   Last modified: October 06. 2009 12:27:21