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/.

Annual temperature extremes given in number of days: 1/ Total number of heatwaves occurring once in 20 years; 2/ Maximum length of the heatwaves occurring once in 20 years; 3/ Hot days: Mean annual number of days with maximum temperature > 25°C; 4/ Tropical days: Mean annual number of days with maximum temperature > 30°C; 5/ Frost days: Mean annual number of days with minimum temperature < 0°C. Heatwaves are defined according to the Royal Meteorological Institute of Belgium when the maximum temperature in Uccle is >= 25°C during at least 5 consecutive days, during which at least 3 days the maximum temperature is >= 30°C. The temperature extremes 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 95th percentiles of the change factors.

Annual, summer and winter mean potential evapotranspiration given in respectively mm/year and mm/3 months and based on the Penman-Monteith definition. The potential evapotranspiration fields are available for the present target year 1975, which corresponds to the middle of the 30-year period 1961-1990.

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 present target year 1975, which corresponds to the middle of the 30-year period 1961-1990.

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.

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 1950, 1951, 1952 and 1954, 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) is 50 cm. 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/.

UNDER EMBARGO - This dataset contains the data on porewater nutrients, sediment granulometry, and pigment concentrations that were collected in the C-power offshore wind farm in spring, summer, and autumn of 2022 for the OUTFLOW project. Data were gathered at increasing distances from the scour protection layer (SPL) of a wind turbine, 7, 15, 25, and 75 m away from the edge. Cores were collected by divers, and a boxcore was used for samples 75 m away. From these cores, porewater nutrients were collected with rhizon samplers, and cores were slices in 0.5 to 2 cm slices, and each slice was analyzed for total organic carbon, total nitrogen, granulometry, and algal pigment concentrations.

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 5m is a representation of the hillshading of the DTM 5m.