Data collection in urban settings is a comprehensive and exhaustive process. Uncertainty plays a vital role in data gathering within cities, as we are immersed in a dynamic system full of multiple interconnections. These interconnections include the implementation of basic infrastructures, facilities, and improvements; mobility and the continual growth of telecoms and its networks; the evolution of economic and social features, built environment development, public spaces planning; and the possibility of a natural disaster or a disease outbreak and their consequences, such as COVID-19.
Fig. 3: Baia Mare and the 5 pilot sites to be recovered through Nature-Based Solutions - NBS - (in red). Source: SPIRE project
Future projections and calculations shape the urban space, and a political and ethical imperative exists to plan for and manage any uncertainties. The process of data collection is becoming more and more demanding, and GIS has evolved into a sub-category of science. On the one hand, data is captured through the digitization of existing information (e.g., scanned maps, digital elevation models, and surveys), which are embedded in the GIS space; on the other hand, data can be transferred or sampled (e.g., digital remote sensing images or digital aerial photographs).
The smart SPIRE iGIS gathers site ground analysis data, which is available thanks to USAMV; one of the members of the SPIRE consortium. The system locates the five pilot sites and provides information about soil analysis:
Fig. 4: Soil measurement. Source: SPIRE project
The phytoremediation techniques applied in Baia Mare remove the heavy metals from the soil using hyperaccumulator plants that can perform phytoextraction. To extract biomass from plants, existing species that currently perform phytoremediation at the pilot sites are integrated into the landscaping plan since they are well-adapted to the local conditions.
According to Order no. 756 of the 3rd of November 1997 (which is still valid today in Romania), the polluted land in Baia Mare falls under the LESS SENSITIVE land use category, which includes all existing industrial and commercial uses; as well as the land areas planned for such uses in the future.
Threshold according to law |
Heavy metal content |
|||
Pb |
Cd |
Cu |
Zn |
|
Normal values (mg/kg DM) |
20 |
1 |
20 |
100 |
Intervention threshold (mg/kg DM) |
250 |
5 |
250 |
700 |
Alert threshold (mg/kg DM) |
1000 |
10 |
250 |
1500 |
Legend: DM= Dry Matter / Dpth= Depth / Cd= Cadmium / Cu= Cupper / Ni= Nickel / Zn= Zinc / Cr= Chromium / Pb= lead / Co= Cobalt / Mn= Manganese / Col= Color
Fig. 5: Threshold and Soil measurement. Data about Heavy Metals. Source: SPIRE project
Also, a massive set of Sentinel-2 (a new fleet of European satellites explicitly designed to provide abundant data and images) specific imagery has been added, including all "cloud-free" images available through the Copernicus programme. Indexes:
RGB (Red, Green, and Blue) refers to a system for representing the colours to be used on a computer display. Red, green, and blue can be combined in various proportions to obtain any colour in the visible spectrum.
PSRI (Plant Senescence Reflectance Index) maximizes the index's sensitivity to the ratio of bulk carotenoids (alpha-carotene and beta-carotene) to chlorophyll. An increase in PSRI indicates increased canopy stress, the onset of canopy senescence, and plant fruit ripening.
NDVI (Normalized Difference Vegetation Index) determines the density of green on a patch of land. The distinct colours (wavelengths) of visible and near-infrared sunlight reflected by the plants can be observed.
NDWI (Normalized Difference Water Index) measures the amount of water in vegetation or the level of moisture saturation in soil.
NDSI (Normalized Difference Soil Index) highlights the difference between the strongest and weakest spectral responses of a target land cover.
BI (Brightness Index) is sensitive to the brightness of soils. High soil brightness is linked with soil humidity and salts in the soil.
CI (Chlorophyll Index) calculates the total amount of chlorophyll in plants.