Safe City GIS

Fire Detection Particulate Matter Content Algal Bloom Content

Development, testing, demonstration and dissemination of innovative Web-based GIS
for threat monitoring, prediction, and risk analysis for the municipal area

Case studies
Fire detection
Fire detection algorithm is being applied to daily NOAA/MetOp AVHRR data for land areas of Poland. The algorithm utilises images acquired during two successive days and uses two reflectance channels: R1 (visible) and R2 (near infrared) as well as three brightness temperature channels: T3 (channel 3B, medium infrared), T4 (thermal infrared 1) and T5 (thermal infrared 2). After cloud screening, the algorithm calculates the Normalized Difference Vegetation Index (NDVI) and its difference for two days. Then the potential fire pixels are chosen as those of large NDVI difference and high T3 brightness temperature values, what is followed by applying several tests to remove false fires.
Air Quality Index estimation
The system is capable of monitoring air quality in selected areas. The applied approach is based on the haze detection and after cloud screening, the Air Quality Index (AQI) is estimated by an empirical formula from AVHRR R1 (visible) channel. In typical ranging of AQI values, it is assumed that values below 50 represent good air quality, from 51 to 100 – for moderate, 101-150 – unhealthy for sensitive groups, 151-200 – unhealthy for the general population, 201-300 – very unhealthy, above 300 – hazardous.
Algae monitoring
The algorithm for algae bloom monitoring assumes the calculation of the modified NDVI from AVHRR R1 and R2 bands. Typical values indicating the zones of higher chlorophyll concentration at sea surface are within the range of -0.4 – -0.1 (differently from the case of land areas with NDVI typical values of 0.4 – 0.6).

City hazard simulations
Blast attack simulation
The blast attack simulation algorithm allows for spatial visualization of the outcome of a blast attack on the city infrastructure. The radii of the structural damage zone (the air pressure over 27 kPa) and severe injures zone (the air pressure below 27 kPa and above normal) are calculated on the basis of the mathematical model used for blast effect assessment. The basic parameters of every simulation are input by the end user via the SafeCityGIS authorised client interface. The results are presented in the form of a structural damage zone circle and severe injures zone circle overlaid on a city topography map.
Chemical attack simulation
The chemical attack or leakage simulation algorithm generates a vector layer containing the maximum extent of the toxic plume under the given conditions on source location, the amount of mixing in the atmosphere, and the wind direction and speed. The algorithm uses the Gaussian plume model and the final shape of the plume is presented in a form which adheres to the NATO ATP-45 norm on Reporting Nuclear Detonations, Biological and Chemical Attacks. The input parameters for simulation are input by the end user via the SafeCityGIS authorised client interface.
Flood simulation
The floodzone estimation and mapping algorithm creates the layer showing the extent of the expected flooded area under the assumed conditions. It uses the following input parameters: layers representing existing water bodies which are treated as a source of overflowing water, the amount water by which the simulated water level is increased over its standard value, and a Digital Terrain Model of the city area, including the artificial constructions essential to the simulation, like water dykes.

Mobile Application
Safe City GIS Mobile Client
The SafeCityGIS mobile client is an application assuring the usage of the system by users of mobile devices like smartphones or tablets. It allows for accessing the system functions by members of civilian services operating in the field during the handling of an emergency.

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