Documentació i publicacions


S I T X E L L. A Territorial Information System for the Multidisciplinary Analysis of Open Spaces in the Province of Barcelona

Carles Castell, Albert Beltran and Meritxell Margall Technical Office of Land Planning and Analysis, Area of Natural Spaces, Barcelona Provincial Council


Land planning based on the existence of a system of functional open spaces must necessarily start with an analysis and evaluation of the characteristics and attributes of this series of spaces from a multidisciplinary perspective, taking into account their natural, economic and social values.

In the Mediterranean region, where the modern-day territory is the result of the ancestral implementation of highly diverse uses leading to a complex mosaic, territorial planning that is both global and multifaceted is necessary when approaching the analysis of the numerous elements and processes that are involved.  Thus, the discipline of landscape ecology constitutes a solid conceptual framework for approaching the classification and analysis of open spaces in order to understand their characteristics and the main dynamics being generated.

Within this context, the Area of Natural Spaces within the Barcelona Provincial Council has implemented the Territorial Information System for the Network of Open Spaces in the province of Barcelona (SITxell), a project devoted to obtaining, organising, analysing and evaluating information on land protected from building.

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The main goal of SITxell is to provide support to the local government's policies on open spaces, so that the territory's socio-economic development is made compatible with the ongoing functionality of the natural systems.

Organisation of SITxell

SITxell is a territorial analysis project organised using the technology of geographical information systems (GIS), aimed at studying and evaluating land protected from building in a holistic way, with the purpose of providing them with structure and making explicit the meaning of the open spaces within the territory as a whole.

SITxell has been constructed on the basis of a multidisciplinary territorial information system which incorporates the numerous facets that converge when defining the characteristics of open spaces; it is flexible in that it allows global or partial analyses of the territory to be made from various different standpoints; it is balanced in that it takes into account the importance of diverse factors of interest; and it is clear, rigorous and distanced from prior assumptions that could bias the analyses, such that the results are reliable and applicable.

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SITxell started with an organisation based on thematic modules which cover the different aspects that define the interest of open spaces and allows the meaning of the spaces to be defined depending on their geological, botanical, faunistic, ecological, social and economic characteristics, taking into account both basic parameters and complex indicators.  The fundamental conceptual organisation of the system is as follows:

  • Environmental Modules. This includes the following modules: geology; hydrology; flora, vegetation and habitats; fauna; landscape ecology; cultural heritage; and landscape.
  • Usage-based Modules. This includes the following modules: socio-economic; sectoral regulations and directives; urban planning and land development; transport infrastructures; and technical services.

Each of the modules contains several different basic information areas - some which were pre-existing while others had to be developed based on diffuse information gathered or newly-generated information - as well as coverage of sectoral assessment, which is produced by transforming and combining the different basic layers.

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Technical characteristics of the project

The IT working environment for the SITxell project is the ArcGIS programme, mainly due to its analytical capacity as well as its compatibility with the main types of cartographic and alphanumerical files.  The project was organised and is mainly managed by ArcInfo, with which the most complex analyses are also carried out.  The programme ArcView is the usual working environment for viewing, making inquiries, combining and transforming the layers, while a user-friendly specific display has been developed in order to enable the different user groups involved, some of whom may be inexpert in the IT language of GIS programmes, to consult the information.

The scale chosen for the SITxell project is 1:50,000, a scale of compromise which allows a sufficiently detailed view in order to show the main features and processes related to the dynamic and planning of the open spaces and to be able to display the role of the different municipalities in this global framework, and which simultaneously is an appropriate scale to undertake the project in the short term.  Using this scale also provides further advantages.  First, there exists a recent cartography of the entire province using this scale, of which the Barcelona Provincial Council is co-owner, and which is to be updated on a regular basis.  Secondly, this is a scale that is frequently used in numerous tasks involved in territorial inventory, analysis and planning, which allows this information to be incorporated into the SITxell system in a relatively simple way.

Nevertheless, SITxell allows for the inclusion of information on more detailed scales (1:25,000, 1:10,000 and 1:5,000), as in fact happens with many of the areas in which coverage is already available, in which the data bases have reached a scale of 1:25,000, even though the reference scale is always kept at 1:50,000 when carrying out global analyses co-ordinating the different thematic modules.

Participants in the project

The following groups of experts currently participate via agreements: The Laboratory of Geographical Information and Teledetection (Laboratori d'Informació Geogràfica i Teledetecció - LIGIT) and the Department of External Geodynamics and Hydrogeology from the Autonomous University of Barcelona; the Group on Geobotany and Vegetation Cartography, and the Bonelli's Eagle Study Group from the University of Barcelona; the Centre for Ecological Research and Forestry Applications (Centre de Recerca Ecològica i Aplicacions Forestals - CREAF); the Study Centre for Mediterranean Rivers (Centre d'Estudi dels Rius Mediterranis - CERM); the Catalan Institute of Ornithology (Institut Català d'Ornitologia - ICO); Minuartia, Environmental Studies; the Farmers' Union; and the Bages County Council.

Likewise, within the Barcelona Provincial Council, in addition to the Area of Natural Spaces, which provided the impetus behind SITxell via its Technical Office of Territorial Planning and Analysis, other participating entities include the Technical Office of Cartography and Local GIS, and the Information Technology and Telecommunications Service.  Other administrative bodies, such as the Generalitat de Catalunya's Department of the Environment, have also facilitated certain basic information areas which have been included in SITxell.

Current status

A good part of the basic information for the SITxell project is now available, mainly data referring to the various areas covered in the environmental module.  Below is a list of the main cartographic bases that have already been included in each of the modules:

  • Geology: Lithology, geomorphology, risks, elements of interest.
  • Hydrology: Aquifers, flood-proneness, river bank habitats and the assessment of shore systems.
  • Flora, vegetation and habitats: Habitats, species and communities of interest, overall assessment.
  • Fauna: Distribution of species, assessment of communities and species indicators.
  • Landscape ecology:  Organisation, flows, indicators of heterogeneity, fragmentation, connectivity, diversity.
  • Cultural heritage: Features of the natural and man-made heritage.
  • Socio-economic: Land uses; analysis of the agricultural, livestock, forestry and mining sectors; urban planning.

Likewise, as a step prior to disseminating the basic information and the sectoral and global analyses for the entire working area, a pilot area of slightly more than 500 km2 has been set aside as representative of the landscape in the province.  This area serves as a basis for trials to test the methods of obtaining information and of transforming and combining the basic areas covered. Thus, in this initial stage, potential problems related to either the structure of the GIS or any of the specific areas, or to the co-ordination among the different working groups participating, will come to light.

Once the potential anomalies and gaps are rectified, the system - now finely-tuned and validated - will be disseminated throughout the entire province, the stage that is currently underway.  Below are some of the preliminary results obtained from the pilot area, which already demonstrate some of the potentialities of the SITxell project within the framework of the strategic planning of open spaces.

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Among the sector-based areas of analysis covered which have been tested to date, we can mention geological risks, geological features of interest, habitat assessment, assessments of bird populations, the establishment of various indexes of landscape ecology (diversity, fragmentation, connectivity) and agricultural dynamism.  As an example, in the present article we have furnished the map on habitat assessment, based on the combination of variables related to the habitats' conservation value, such as rarity, frequency and successional status (Figure 1).  We have also supplied the map on agricultural dynamism, through the comprehensive analysis of the economic potential and the agricultural structure of each type of use (Figure 2).  In both cases, the analyses enable the open spaces to be classified according to their attributes and values, and ultimately in terms of their degree of interest.

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On the basis of these sectoral analyses, several global analyses have also been tested, in which the areas covered are combined in order to obtain a multidisciplinary assessment of open spaces.  As an example, a possible global assessment map is shown (Figure 3) using five categories, which are the product of the following combination of its sectoral attributes:

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  • Area of high environmental interest:  This includes the areas of maximum interest due to their geological features, flora, vegetation, habitats, birds or landscape, and, as a result, those that would need specific protection in order to ensure the preservation of their existing values.
  • Matrix of environmental interest: This encompasses areas of high interest due to their flora, vegetation, habitats, birds or landscape connectivity, or because they have hydrological or geomorphological risks.  These areas require basic protection consisting of making their uses compatible with their existing values and risks.
  • Area of high agricultural interest:  This category corresponds to the areas with the greatest degree of agricultural dynamism, in which the agricultural, livestock and forestry sectors have a significant presence from the social and economic standpoint.
  • Built-up area:  Areas currently occupied by population nuclei and housing developments.
  • Area not included in any of the previous categories:  This is made up of the areas that exhibit none of the essential features needed to be included in one of the previous categories, and as a result whose function within the system of open spaces is less clearly defined.  Depending on their characteristics, they could be used, if need be, for urban development with a relatively low impact on the territory (built-up areas, urban or periurban parks), or conversely their natural, agricultural, forestry or landscape values could be fostered through appropriate management.

Based on this overall assessment, various applications can be developed in terms of land planning for open spaces.  One of these consists of setting forth strategic avenues of land development (Figure 4), which are more broad conceptual directives on a macro-territorial scale than specific land use proposals, since many more parameters of analysis would need to be taken into account in order to make specific proposals.  The strategic avenues propose the organisation of open spaces into functional groups based on establishing areas that are homogeneous to a greater or lesser degree in terms of their attributes, and which could thus be subject to similar planning and/or management.

As an example of this, we can see the potential establishment of an Area of Strict Protection, through the appropriate designation; a Forest Matrix, where the duly managed agricultural uses are perfectly compatible with the conservation of the environmental values; an Area of Forest Management, where specific management would have to be planned in an effort to improve the forests; an Agro-forestry Mosaic, where the present combination of agricultural, livestock and forestry uses would have to be conserved; an Agricultural Production Area, where the agricultural uses would have to be fostered, simultaneously making them compatible with the maintenance of the land values; and a Dynamic Urban Area, which would include the current urban areas and areas of possible expansion, where it is necessary to minimise the impact of man-made features on the land through appropriate planning.

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Another possible application of the SITxell analysis would consist of uncovering possible large-scale discrepancies between the assessment of open spaces and current urban planning.  This exercise would, for example, facilitate the assessment of trends in urban growth around current population nuclei, where new urban settlements are frequently planned in areas with significant agricultural interest or with environmental risks instead of first occupying areas that are more appropriate for being built up.  Another example would be the detection of developments located in areas of significant natural interest which are frequently allowed to expand.

These potential applications of SITxell are simply the initial trials carried out in the pilot area on the basis of only part of the sectoral information.  From now on, it will be essential to complete and update the basic information as well as to fine-tune and validate the system of analysis in order to be able to apply it to all the open spaces in the province of Barcelona.


These initial phases in the SITxell project already demonstrate the usefulness of landscape ecology as a conceptual framework for territorial planning in the Mediterranean context.  The importance of having in-depth knowledge of the features and processes that participate in the dynamic of open spaces by defining, characterising and inter-relating their attributes is clear.

Any consideration of land use based on this knowledge needs to have a corresponding geographic information system as a powerful, versatile instrument for land analysis and diagnosis.  Having a clear theoretical framework and useful instruments will enable certain implementation trends to be corrected and missteps and frictions brought about by land occupation to be re-guided, and it will foster management practices that favour the value of the open spaces, making socio-economic development compatible with the preservation of the functionality of the natural systems.

Captions below the figures

Figure 1.

Index of habitat assessment based on variables such as rarity, successional status, frequency and form of territorial occupation (Group on Geobotany and Vegetation Cartography, University of Barcelona).

Figure 2.

Index of dynamism of the agricultural sector, based on variables linked to both economic potential and the agricultural structure itself (Rural Area, Farmers' Union).

Figure 3.

Overall territorial assessment.

Figure 4.

Strategic avenues for planning open spaces.