The zones are used as reporting units of the air quality in Belgium. These zones are defined based on Article 3 of the 2004/107/EC Directive and Article 4 of the 2008/50/EC Directive. A zones shall mean a part of the territory of a Member State, as delimited by that Member State for the purposes of air quality assessment and management (source: 2008/50/EC).2008/50/EC Article 4: Establishment of zones and agglomerations: Member States shall establish zones and agglomerations throughout their territory. Air quality assessment and air quality management shall be carried out in all zones and agglomerations.

An hillshade is a homogeneous and regular points grid, indicating the grey tone deriving from their orientation relative to the chosen fictitious light source. The Hillshade DTM 1m is a representation of the hillshading of the DTM 1m.

A climate normal is an average over a 30-years period. The period 1981-2010 is the current reference period recommended by the World Meteorological Organization (WMO). Recent climate normals are available for any locations in Belgium and several parameters including air temperature, precipitations and solar radiation. Climate normals for the reference period 1981-2010 are available for air temperature, precipitation and derived parameters (e.g., annual number of summer days, annual number of precipitation days, etc.). For solar radiation, the reference period had to be adjusted to 1984-2013 because of data availability. These climate normals are available as maps and as table for each Belgian municipality.

Network of marks whose planimetric coordinates are known with precision according to the reference systems which are used in Belgium.

The DTM 5m, digital terrain model at 5m-resolution, is a homogeneous and regular point grid indicating the height of the ground level in order to model its surface, without taking into account objects on the surface such as buildings and vegetation. The DTM 5m is the result of the assembly of different data coming from various sources and with different coordinate systems and resolutions. The DTM 1m is achieved by interpolating in Lambert 2008 source data in Lambert 72 and at a 1m-resolution from the Flemish (2013-2015) and Brussels (2021) regions, and by adding Lambert 2008 data at 1m-resolution from the Walloon Region (2021-2022). The DTM 5m is obtained by resampling of the DTM 1m. In addition, the DTM 5m is improved and updated internally using direct photogrammetric surveys based on the most recent aerial photographs.

Annual and seasonal precipitation indices given in number of days: 1/ Wet days: Number of days with precipitation > 0.1 mm/day for winter, autumn, spring, summer; 2/ Dry days: Number of days with precipitation < 0.1 mm/day for winter, autumn, spring, summer; 3/ Average length of dry spells: Mean duration of minimum three consecutive days with precipitation < 0.1 mm/day; 4/ Maximum length of dry spells: Longest period of minimum three consecutive days with precipitation < 0.1 mm/day, occurring once in 20 years. The precipitation indices are available for the future target year 2085, which corresponds to the middle of the 30-year period 2071-2100, and for mean and high impact scenarios corresponding respectively to the 50th, and 5th or 95th percentiles of the change factors.

The DSM 1m, digital surface model at 1m-resolution, is a homogeneous and regular point grid indicating the height of the Earth’s surface level in order to model its landscape, also including objects on the surface such as vegetation and buildings. The DSM 1m is achieved by interpolating in Lambert 2008 source data in Lambert 72 and at a 1m-resolution from the Flemish (2013-2015) and Brussels (2021) Regions, and by adding Lambert 2008 data at 1m-resolution from the Walloon Region (2021-2022).

The areas not included in the settelement area considered to be categories of open space. However, open space should not be confused with green or undeveloped space. The settelement area also includes various forms of non-paved green space, such as gardens and parks or sports grounds and these are counted as developed area. These indicators show the total area of open space expressed in m² en de part of open area in relation to the total surface per administrative unit (region, province, district and municipality) for Flanders.

This dataset contains the spatial metadata of the collection of historical aerial photographs (1946–2007) of the National Geographic Institute (NGI). The aerial photographs themselves are not part of the dataset. The collection comprises more than 72,000 aerial photographs. The images are predominantly panchromatic (black and white). From the late 1970s onwards, colour images were also acquired, and from late 2004 onwards all images were acquired in colour. The analogue aerial photographs in the collection were scanned at high resolution. This specific dataset comprises three layers: the centre points (centroids) of the individual aerial photographs, the footprints (the outlines of the area on the ground covered by each photograph) and the flight paths of the aircraft used during image acquisition. For each aerial photograph, all known metadata are included in the attribute table, such as the acquisition date, the flight and the strip, the dimensions, the scale, the ground resolution, the radiometry (black and white or colour), the coordinates of the centre point and the camera, lens and film used. These data make it possible to look up which historical aerial photographs are available for a given location and period, and what the characteristics of each photograph are. The data can be consulted via the corresponding web service (WFS). The aerial photographs can be ordered in high resolution via https://shop.ngi.be/nl/luchtfotos/.

This dataset contains historical orthophoto mosaics based on available aerial photographs covering parts of the Belgian territory. Orthophotos are aerial photographs that have been geometrically corrected (orthorectified) to eliminate distortions caused by terrain relief, lens distortion, and camera tilt. Unlike raw aerial imagery, orthophotos have a uniform scale and accurate geometry, making them suitable for cartography, measurements, and visual analysis. This specific dataset includes historical orthophotos from 1995, 1997, 1998 and 1999, derived from aerial surveys carried out by the National Geographic Institute (NGI). During this period, only analogue aerial photographs are available. The analogue images were scanned at high resolution and orthorectified. The resulting orthophotos were assembled into mosaics and georeferenced in the Lambert 2008 coordinate system. All orthophotos are panchromatic (black and white). The ground resolution (GSD) varies between 25 cm and 100 cm, depending on the sensor used and the surveyed area. The spatial coverage of this dataset is limited to the areas for which aerial photographs were available during the mentioned period. The data can be visualized via the corresponding web services (WMS/WMTS). The orthophotos and the original aerial photographs can be ordered in high resolution via https://shop.ngi.be/nl/luchtfotos/.