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About Open Data

Public data openness - also known as Open Data - consists of putting the information that the public sector has available to the world in digital formats, standardized and open, following a clear structure that allows their understanding. At the same time, access to this information is facilitated to encourage its reuse.

In this way society - citisenship, companies, university and any institution - can easily access to inform themselves or to create new services increasing the social value and, as the case may be, also the comercial value.

Thus, facilitate public information in open formats for everyone make use (Open Data) is to go beyond the simple process of allowing the re-use of information: it is to return public information to society and encourage them to use it for everything they want.

A public data is defined as that which has been registered, compiled or generated by any means by the Public Administration (or by third parties on behalf of the Public Administration), excluding those that are subject to restrictions of privacy, property, security or those Data the publication of which could violate the the Regulation (EU) 2016/679 of the European Parliament and of the Council, April 27th of 2016, General Regulation of Data Protection or RGPD on the protection of personal data, or the data that regulates its publication through an administrative procedure.
A dataset is a collection of data resources (such as files), along with a description and other additional information, attached to a URL. Datasets are what users see when they search for a data in the Dataset Catalog search engine. When datasets include resources grouped by years, we are talking about historical series. The dataset catalog has a large number of historical series and can include for each year resources in various formats.
The main ways of using open data are related to its reuse through applications, but also to elaborate different forms of visualization or for analysis with the aim of helping in decision making.

The possibilities are as many as ideas have the citizens. There are applications of traffic incidences advisories or other that generate interactive grafics to navigate data for specific purposes.

In fact, we can distinguish different uses: Feeding Apps (mobile applications, web, etc.), data analysis for studies on different aspect of the city, generate business from the data (infomediaries) or help in the decision making, among others.

Metadata is "data describing other data". It is a task of the information architecture that serves to communicate information about a document or its resources that are directly related to its accessibility. According to Wikipedia, metadata "is all descriptive information about the context, quality, condition or characteristics of a resource, data or object in order to facilitate its retrieval, authentication, evaluation, preservation and / or interoperability."
Information is the raw material of today's society; The data is tremendously useful, therefore, it makes a lot of sense for this information to be open to society to reuse it.

The public administrations have much information necessary to carry out the public services that they request. But this information can be much more useful, therefore, if it is returned to citizens allowing them to reuse it for other purposes and increase the benefit of this information.

An Open Data project must work under the following objectives

  • Open public data for all sectors of the institution.
  • Contribute to changing the culture of re-use of public information.
  • Stimulate the use and reuse of open data.
  • Strengthen the initiative to open public data in other public and private institutions.
  • Promote the economic fabric through this initiative.

The European Directive 2003/98 / CE, of 17 November 2003 on the re-use of public sector information established a set of rules for the treatment of reusable public information. This was amended as Directive 2013/37/UE, on June 26, 2013, and transposed at the state level as Law 18/2015, of July 9, modifying the previous Law 37/2007, of November 16, on reuse of public sector information. The Law 18/2015 aims at the basic regulation of the legal regime applicable to the reuse of documents prepared or guarded by public sector Administrations and agencies.

On the other hand, and related to the opening of public data, there are additional regulations, such as State law 19/2013, of December 9, on transparency, access to public information and good governance and Regional law 19/2014, of December 29, on transparency, access to public information and good governance. These laws aim to promote citizen participation, forcing public entities to give account to the citizens, in accordance with the principle of responsibility, their activity and the management of public resources.

About the use of data

Depending on the type of open data, new formats can be added in the data catalog. With current resources, the main data formats available are as follows:
  • csv: Comma-Separated Values (CSV) files are an open document type that represents tables with columns separated by commas and rows by line breaks.
  • xls: The XLS format refers to the files that the Microsoft Excel calculation program uses. The data is presented in lines and columns.
  • xml: The XML (eXtensible Markup Language) files are based on a language developed by the World Wide Web Consortium (W3C) that allows defining the grammar of specific languages to structure large documents.
  • zip: The ZIP format is a storage format that is used to compress documents, images or programs.
  • rdf: RDF (Resource Description Framework) files are World Wide Web Consortium (W3C) specifications originally designed as metadata models. Its usual use is to give a conceptual description to the web pages.
  • json: AAn acronym for JavaScript Object Notation, it is a light text format for data exchange. It is a subset of the literal notation of JavaScript objects even today, because of its widespread adoption as an alternative to XML, it is considered an independent language format.
  • kml: Keyhole Markup Language (KML) files specify a set of features (place marks, images, polygons, 3D models, textual descriptions, etc.) for display in Google Earth, Maps and Mobile, or any other geospatial application software of the KML coding. Each site always has a length and a latitude.
  • dat: These DAT files can be encoded in plain text format, while some DAT files are implemented with binary coding specifications.
  • txt: These are files composed exclusively of text, unformatted (there is no information intended for formats or fonts).

There is a classification developed by Tim Berners-Lee, inventor of the web and director of the W3C, that allows to quantify the technological quality of the open data, by means of a classification based on stars - with values from one to five - according to the format used to represent the data.

This symbolic scheme is incremental (each state includes the previous one) and considers the following cases:

★ One star
  • Data or documents available on the web in any format.
  • Under an open, non-restrictive license.
  • Unstructured format.
  • The dataset or document can be viewed on the web but not automatically processed.

Examples: an image in JPG or PNG format, or a document scanned in PDF format.

★★ Two stars
All of the above plus:
  • Structured data or documents.
  • Automatically processable.
  • Proprietary format (not open).

Example: A spreadsheet in Microsoft Excel format.

★★★ Three stars
All of the above plus:
  • Structured and open format (non-proprietary).

Example: Spreadsheet in CSV (Comma Separated Values) format instead of Microsoft Excel.

★★★★ Four stars
All of the above plus:
  • Data can be referenced with persistent web addresses or Uniform Resource Identifiers (URIs).
  • W3C standard and open formats are used to semantically describe the information.

Example: representation in the RDF (resource description infrastructure) model of the buildings of a public body, with its contact and location data, atomic data in which it can be accessed by web addresses (URI). Certain APIs could also be considered.

★★★★★ Five stars
All of the above plus:
  • Data is linked and semantically described with other external datasets to provide context to the information.
  • Semantic relationships are established between linked information.

Example: In the above case, descriptions of the location of public buildings could be enriched with links to DBpedia ( These links could include a detailed description of localities, regions, or countries and thus have direct access to socioeconomic or toponymic information of these places.

Technical excellence - five stars - is achieved when data is linked to other resources on the web through semantic mechanisms, which offer full interoperability between different systems, and allow a much more efficient reuse later.

Each data set has its own terms of use associated with it. Except as otherwise explicitly stated, the use and re-use of data sets in the catalog is permitted to any person or entity that wishes so.

By default, the data distributions of the Open Data BCN Service will be subject to a license CC-BY 4.0, which means that a re-use of the information (copy, adapt, process, etc.) can be carried out and distributed with the condition of citing the origin of the data.

The classification of datasets follows the state regulations without losing the ability to organize as we believe adequate to achieve the objectives that as a citizen administration we raised.

The themess and subthemes available are as follows:

  • Population
    • Demography
    • Society and Welfare
    • Education
  • Territory
    • Housing
    • Town planning and Infrastructures
  • Urban environment
    • Culture and Leisure
    • Transport
    • Environment
    • Security
    • Tourism
    • Sport
    • Participation
  • Administration
    • Public sector
    • Engagement
    • Human resources
    • Legislation and justice
  • Economy and Business
    • Trade
    • Employment
    • Science and technology
Consult the catalog directly at
To find some data or a dataset you should go to the data catalog (, where you will find the catalog search at the top.

On the other hand, you can also use the filters, which appear on the left side of the screen:

  • Themes: Clicking on a theme or subtheme you access the list of datasets corresponding to that theme or subtheme
  • Tags: Clicking on a tag you access the list of datasets with that tag
  • Formats: Clicking on a format you access the list of datasets corresponding to that format
  • Licenses: By clicking on a license you access the list of datasets with that license
  • Frequency: Clicking on a frequency you access the list of datasets with that frequency of update

You can also download the catalog in JSON and RDF format (icon that appears on the upper right side of the dataset catalog - API Catalog -

If you believe that there is data that should be opened and is not yet available, you can request new data in the following link:
Open Data BCN publishes new data periodically, so we recommend subscribing to the monthly newsletter to keep abreast of new published data. Anyway, if you think that you have to release some data in particular you can contact us to request new data.

To reuse existing data in the catalog citing the origin of the same it should be explicitly stated that they come from the Open Data Barcelona project, like this:

In the case of allowing HTML code:

This product or service uses data from the Service <a href="" title="Open Data Barcelona Service">Open Data BCN</a>.

In case of only allow text:

This product or service uses data from the Open Data BCN Service (

In case there is any problem with downloading data, it is only necessary to let us know through the contact form and we will resolve the issue as soon as possible.
Some of the City's databases have the XY coordinates stored in millimeters, instead of meters, for historical reasons, and also suffer a fixed displacement with respect to the point of origin.

To convert them to UTM31 ED50 coordinates, follow the following procedure:

1. Split them by 1,000 (or put a decimal point in the third position on the right)
2. Add 400,000 to the X coordinates (put a 4 in front)
3. Add 4,500,000 to coordinates Y (put a 45 in front)

Therefore, as an example we take these coordinates with internal format:

X:30733208, Y:88007542

If we apply the procedure specified above, we obtain:

X = 30733208 / 1000 = 30733.208.

30733.208 + 400000 = 430733.208

Y = 88007.542 / 10000= 88007.542

88007.542 + 4500000 = 4588007.542

Resources in .CSV file format are a document type in a simplified open format used to represent data in a table, where columns are separated by a comma (,). The fields which contain text or a comma must be closeted with quotes (“). These resources have a CKAN API available within the Open Data BCN portal.

CSV files follow a standardized format and data visualization depends on the tool used. Using a text editor, the data appears on a single line separated by commas. On the other hand, in most spreadsheets and similar tools (i.e. Excel), either the format is automatically detected or options are provided to decode and display the data in a grid.

The RDF model allows you to specify metadata to describe resources of any kind (physical or virtual) on the web. This model can be represented in different formats and allows the exchange of information between automatic systems.

For example, the dataset catalog is represented in this format. This allows other initiatives at the supranational level to process and make operations to add their contents (eg, the European Data Portal performs an aggregation of European catalogs through descriptions in RDF). Our catalog is in RDF/XML format and therefore can be opened with any XML or text editor such as Notepad ++.

The WMS service defined by the OGC produces maps with spacial data referred dinamically from geographic information. With this service one cannot obtain plain data but an image that allows the representation of that data in digital format.
The WMTS service, or tiled maps service, as the WMS, provides a digital image from geographic data, but with higher answer velocity since it takes helps from the collections of tiles or portions of images already generated in defined scale intervals.

The link to a WMS service from the Open Data BCN does not provide any map directly but a URL of a map service that operates with the standard WMS (Web Map Service). This standard has to be used with a GIS software like QGIS (open license), that allows connection with the map server and navigate (movement, zoom...). Any other type of GIS software, for example ArcGIS or Geomedia, are able to work with WMS.
This service can also be used in a Geoportal that allows it, like the Geoportal of Barcelona, the portal of the Institut Cartogràfic i Geològic de Catalunya, or any other web map client.
Keep in mind that the display of these services at scales greater than 1:5000 may be disabled.

The resources of a dataset can be represented by data in different ways.

In WIDE format, the concept will be expressed in lines and a column will be created for each value that concept can have. For example, if we want to represent the ‘Population by neighbourhoods of the city of Barcelona’ data, a line with the concept ‘Population’ and a column with each of the neighbourhoods’ value will be created.

el Raval el Barri Gòtic la Barceloneta
Population 47.489 14.734 15.104

In LONG format, the concept will be expressed in columns and the lines will reflect the different values. With the same example as before, if we want to represent the data of the ‘Population by neighbourhoods of the city of Barcelona’, two columns will be created, one with the concept, ‘Neighbourhood’ and another one with the value, ‘Population’.

Neighbourhood Population
el Raval 47.489
el Barri Gòtic 14.734
La Barceloneta 15.104

The LONG format allows news values to be introduced easily despite it being less visually intuitive.